First Commit

Signed-off-by: YuutaW <17158086+Trumeet@users.noreply.github.com>

51 files changed, 1559 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1306e65
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,10 @@
+*.iml
+.gradle
+/local.properties
+/.idea/
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+/repo/
\ No newline at end of file
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..8923a4c
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,18 @@
+jdk: oraclejdk8
+language: android
+android:
+  components:
+    - build-tools-28.0.3
+    - android-28
+before_install:
+  - git clone https://github.com/Trumeet/Maven.git ./repo
+  - "./gradlew exportVersion"
+  - export VERSION=$(cat version.txt)
+script:
+  - "./gradlew :library:uploadArchives"
+deploy:
+  provider: script
+  script: chmod +x ./deploy_repo.sh && ./deploy_repo.sh
+  on:
+    repo: Trumeet/Flow
+    branch: master
\ No newline at end of file
diff --git a/app/.gitignore b/app/.gitignore
new file mode 100644
index 0000000..796b96d
--- /dev/null
+++ b/app/.gitignore
@@ -0,0 +1 @@
+/build
diff --git a/app/build.gradle b/app/build.gradle
new file mode 100644
index 0000000..b76887d
--- /dev/null
+++ b/app/build.gradle
@@ -0,0 +1,35 @@
+apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-android'
+
+android {
+    compileSdkVersion 28
+    defaultConfig {
+        applicationId "moe.yuuta.flow.demo"
+        minSdkVersion 14
+        targetSdkVersion 28
+        versionCode 1
+        versionName "1.0"
+        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+    }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    testImplementation 'junit:junit:4.12'
+    implementation project(':library')
+    implementation 'androidx.fragment:fragment:1.0.0'
+    implementation 'androidx.appcompat:appcompat:1.0.2'
+    androidTestImplementation 'com.android.support.test:runner:1.0.2'
+    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+}
+repositories {
+    mavenCentral()
+}
diff --git a/app/proguard-rules.pro b/app/proguard-rules.pro
new file mode 100644
index 0000000..f1b4245
--- /dev/null
+++ b/app/proguard-rules.pro
@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile
diff --git a/app/src/androidTest/java/moe/yuuta/flow/ExampleInstrumentedTest.java b/app/src/androidTest/java/moe/yuuta/flow/ExampleInstrumentedTest.java
new file mode 100644
index 0000000..2569893
--- /dev/null
+++ b/app/src/androidTest/java/moe/yuuta/flow/ExampleInstrumentedTest.java
@@ -0,0 +1,26 @@
+package moe.yuuta.flow;
+
+import android.content.Context;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
+ */
+@RunWith(AndroidJUnit4.class)
+public class ExampleInstrumentedTest {
+    @Test
+    public void useAppContext() {
+        // Context of the app under test.
+        Context appContext = InstrumentationRegistry.getInstrumentation().getTargetContext();
+
+        assertEquals("moe.yuuta.flow", appContext.getPackageName());
+    }
+}
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
new file mode 100644
index 0000000..22133a8
--- /dev/null
+++ b/app/src/main/AndroidManifest.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    package="moe.yuuta.flow">
+    <uses-permission android:name="android.permission.VIBRATE" />
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/AppTheme"
+        tools:ignore="GoogleAppIndexingWarning">
+        <activity android:name=".MainActivity">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>
\ No newline at end of file
diff --git a/app/src/main/java/moe/yuuta/flow/MainActivity.java b/app/src/main/java/moe/yuuta/flow/MainActivity.java
new file mode 100644
index 0000000..cba4bbd
--- /dev/null
+++ b/app/src/main/java/moe/yuuta/flow/MainActivity.java
@@ -0,0 +1,103 @@
+package moe.yuuta.flow;
+
+import android.os.Bundle;
+import android.os.Vibrator;
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.app.AppCompatDelegate;
+
+import java.util.Arrays;
+
+// You don't need to use AppCompatActivity and AppCompat styles.
+public class MainActivity extends AppCompatActivity {
+    private static final String TAG = MainActivity.class.getSimpleName();
+
+    private FlowFragment mFragment;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
+        Log.i(TAG, "onCreate()");
+        if (mFragment == null) {
+            mFragment = new FlowFragment();
+            mFragment.setPages(Arrays.asList(new Page1(), new Page2(), new Page3()));
+            getSupportFragmentManager()
+                    .beginTransaction()
+                    .replace(android.R.id.content, mFragment)
+                    .commitAllowingStateLoss();
+            Log.i(TAG, "done");
+        }
+    }
+
+    public static class Page1 extends PageFragment {
+        public Page1() {
+            mInfo = new FlowInfo(new HeaderConfig("Page 1", "lol", false), null);
+        }
+
+        @Override
+        public void onCreate(@Nullable Bundle savedInstanceState) {
+            super.onCreate(savedInstanceState);
+        }
+
+        @Nullable
+        @Override
+        public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
+            TextView view = new TextView(requireContext());
+            view.setText("Page 1");
+            return view;
+        }
+    }
+
+    public static class Page2 extends PageFragment {
+        public Page2() {
+            mInfo = new FlowInfo(new HeaderConfig("Page 2", "built with love", false), null);
+        }
+
+        @Nullable
+        @Override
+        public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
+            TextView view = new TextView(requireContext());
+            view.setText("Page 2");
+            mInfo = new FlowInfo(new HeaderConfig("Page 2 lol", "built with love", false),
+                    new NavigationBarConfig("2", "1", View.VISIBLE, View.VISIBLE, View.VISIBLE, getHostFragment().getGeneralFlowNavListener(),
+                            getHostFragment().getGeneralFlowNavListener()));
+            getHostFragment().notifyCurrentFlowInfoUpdated();
+            return view;
+        }
+    }
+
+    public static class Page3 extends PageFragment {
+        public Page3() {
+            mInfo = new FlowInfo(new HeaderConfig("Page 3", "zzz~", true), null);
+        }
+
+        @Nullable
+        @Override
+        public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
+            TextView view = new TextView(requireContext());
+            view.setText("Page 3");
+            return view;
+        }
+
+        @Override
+        public boolean onBackPressed() {
+            Vibrator vibrator = (Vibrator) requireContext().getSystemService(VIBRATOR_SERVICE);
+            vibrator.vibrate(new long[]{50L, 30L}, 1);
+            return true;
+        }
+    }
+
+    @Override
+    public void onBackPressed() {
+        if (mFragment != null && mFragment.onBackPressed()) return;
+        super.onBackPressed();
+    }
+}
diff --git a/app/src/main/res/drawable-v24/ic_launcher_foreground.xml b/app/src/main/res/drawable-v24/ic_launcher_foreground.xml
new file mode 100644
index 0000000..1f6bb29
--- /dev/null
+++ b/app/src/main/res/drawable-v24/ic_launcher_foreground.xml
@@ -0,0 +1,34 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillType="evenOdd"
+        android:pathData="M32,64C32,64 38.39,52.99 44.13,50.95C51.37,48.37 70.14,49.57 70.14,49.57L108.26,87.69L108,109.01L75.97,107.97L32,64Z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX="78.5885"
+                android:endY="90.9159"
+                android:startX="48.7653"
+                android:startY="61.0927"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:pathData="M66.94,46.02L66.94,46.02C72.44,50.07 76,56.61 76,64L32,64C32,56.61 35.56,50.11 40.98,46.06L36.18,41.19C35.45,40.45 35.45,39.3 36.18,38.56C36.91,37.81 38.05,37.81 38.78,38.56L44.25,44.05C47.18,42.57 50.48,41.71 54,41.71C57.48,41.71 60.78,42.57 63.68,44.05L69.11,38.56C69.84,37.81 70.98,37.81 71.71,38.56C72.44,39.3 72.44,40.45 71.71,41.19L66.94,46.02ZM62.94,56.92C64.08,56.92 65,56.01 65,54.88C65,53.76 64.08,52.85 62.94,52.85C61.8,52.85 60.88,53.76 60.88,54.88C60.88,56.01 61.8,56.92 62.94,56.92ZM45.06,56.92C46.2,56.92 47.13,56.01 47.13,54.88C47.13,53.76 46.2,52.85 45.06,52.85C43.92,52.85 43,53.76 43,54.88C43,56.01 43.92,56.92 45.06,56.92Z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000" />
+</vector>
diff --git a/app/src/main/res/drawable/ic_launcher_background.xml b/app/src/main/res/drawable/ic_launcher_background.xml
new file mode 100644
index 0000000..0d025f9
--- /dev/null
+++ b/app/src/main/res/drawable/ic_launcher_background.xml
@@ -0,0 +1,170 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillColor="#008577"
+        android:pathData="M0,0h108v108h-108z" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M9,0L9,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,0L19,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,0L29,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,0L39,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,0L49,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,0L59,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,0L69,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,0L79,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M89,0L89,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M99,0L99,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,9L108,9"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,19L108,19"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,29L108,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,39L108,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,49L108,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,59L108,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,69L108,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,79L108,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,89L108,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,99L108,99"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,29L89,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,39L89,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,49L89,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,59L89,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,69L89,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,79L89,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,19L29,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,19L39,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,19L49,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,19L59,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,19L69,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,19L79,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+</vector>
diff --git a/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml b/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml
new file mode 100644
index 0000000..eca70cf
--- /dev/null
+++ b/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>
\ No newline at end of file
diff --git a/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml b/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml
new file mode 100644
index 0000000..eca70cf
--- /dev/null
+++ b/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>
\ No newline at end of file
diff --git a/app/src/main/res/mipmap-hdpi/ic_launcher.png b/app/src/main/res/mipmap-hdpi/ic_launcher.png
new file mode 100644
index 0000000..898f3ed
--- /dev/null
+++ b/app/src/main/res/mipmap-hdpi/ic_launcher.png
diff --git a/app/src/main/res/mipmap-hdpi/ic_launcher_round.png b/app/src/main/res/mipmap-hdpi/ic_launcher_round.png
new file mode 100644
index 0000000..dffca36
--- /dev/null
+++ b/app/src/main/res/mipmap-hdpi/ic_launcher_round.png
diff --git a/app/src/main/res/mipmap-mdpi/ic_launcher.png b/app/src/main/res/mipmap-mdpi/ic_launcher.png
new file mode 100644
index 0000000..64ba76f
--- /dev/null
+++ b/app/src/main/res/mipmap-mdpi/ic_launcher.png
diff --git a/app/src/main/res/mipmap-mdpi/ic_launcher_round.png b/app/src/main/res/mipmap-mdpi/ic_launcher_round.png
new file mode 100644
index 0000000..dae5e08
--- /dev/null
+++ b/app/src/main/res/mipmap-mdpi/ic_launcher_round.png
diff --git a/app/src/main/res/mipmap-xhdpi/ic_launcher.png b/app/src/main/res/mipmap-xhdpi/ic_launcher.png
new file mode 100644
index 0000000..e5ed465
--- /dev/null
+++ b/app/src/main/res/mipmap-xhdpi/ic_launcher.png
diff --git a/app/src/main/res/mipmap-xhdpi/ic_launcher_round.png b/app/src/main/res/mipmap-xhdpi/ic_launcher_round.png
new file mode 100644
index 0000000..14ed0af
--- /dev/null
+++ b/app/src/main/res/mipmap-xhdpi/ic_launcher_round.png
diff --git a/app/src/main/res/mipmap-xxhdpi/ic_launcher.png b/app/src/main/res/mipmap-xxhdpi/ic_launcher.png
new file mode 100644
index 0000000..b0907ca
--- /dev/null
+++ b/app/src/main/res/mipmap-xxhdpi/ic_launcher.png
diff --git a/app/src/main/res/mipmap-xxhdpi/ic_launcher_round.png b/app/src/main/res/mipmap-xxhdpi/ic_launcher_round.png
new file mode 100644
index 0000000..d8ae031
--- /dev/null
+++ b/app/src/main/res/mipmap-xxhdpi/ic_launcher_round.png
diff --git a/app/src/main/res/mipmap-xxxhdpi/ic_launcher.png b/app/src/main/res/mipmap-xxxhdpi/ic_launcher.png
new file mode 100644
index 0000000..2c18de9
--- /dev/null
+++ b/app/src/main/res/mipmap-xxxhdpi/ic_launcher.png
diff --git a/app/src/main/res/mipmap-xxxhdpi/ic_launcher_round.png b/app/src/main/res/mipmap-xxxhdpi/ic_launcher_round.png
new file mode 100644
index 0000000..beed3cd
--- /dev/null
+++ b/app/src/main/res/mipmap-xxxhdpi/ic_launcher_round.png
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
new file mode 100644
index 0000000..28c31c2
--- /dev/null
+++ b/app/src/main/res/values/strings.xml
@@ -0,0 +1,6 @@
+<resources>
+    <string name="app_name">Flow</string>
+    <style name="AppTheme" parent="Theme.AppCompat.DayNight.NoActionBar">
+        <item name="positiveButtonStyle">@style/Widget.AppCompat.Button.Colored</item>
+    </style>
+</resources>
diff --git a/app/src/test/java/moe/yuuta/flow/ExampleUnitTest.java b/app/src/test/java/moe/yuuta/flow/ExampleUnitTest.java
new file mode 100644
index 0000000..84848a0
--- /dev/null
+++ b/app/src/test/java/moe/yuuta/flow/ExampleUnitTest.java
@@ -0,0 +1,17 @@
+package moe.yuuta.flow;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
+ */
+public class ExampleUnitTest {
+    @Test
+    public void addition_isCorrect() {
+        assertEquals(4, 2 + 2);
+    }
+}
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
new file mode 100644
index 0000000..7f1896f
--- /dev/null
+++ b/build.gradle
@@ -0,0 +1,43 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+
+buildscript {
+    ext.kotlin_version = '1.3.30'
+    repositories {
+        google()
+        jcenter()
+        
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:3.5.0-alpha03'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+
+        // NOTE: Do not place your application dependencies here; they belong
+        // in the individual module build.gradle files
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        jcenter()
+        
+    }
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}
+
+def commit = 'git rev-list --count HEAD'.execute([], project.rootDir).text.trim()
+def ver = "$commit"
+
+ext {
+    version = ver
+}
+
+task exportVersion(type: Exec) {
+    commandLine 'sh'
+    doLast {
+        file("$projectDir/version.txt").text = """$ver"""
+    }
+}
\ No newline at end of file
diff --git a/deploy_repo.sh b/deploy_repo.sh
new file mode 100644
index 0000000..1bcf137
--- /dev/null
+++ b/deploy_repo.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+setup_git() {
+  git config --global user.email "${MAVEN_PUSH_EMAIL}"
+  git config --global user.name "${MAVEN_PUSH_NAME}"
+}
+
+commit_files() {
+  git add .
+  git commit --author "${MAVEN_PUSH_NAME} <${MAVEN_PUSH_EMAIL}>" -m "Upload"
+}
+
+upload_files() {
+  git push https://Trumeet:${MAVEN_PUSH_TOKEN}@github.com/Trumeet/maven.git HEAD:master
+}
+
+cd repo
+setup_git
+commit_files
+upload_files
+cd ..
\ No newline at end of file
diff --git a/gradle.properties b/gradle.properties
new file mode 100644
index 0000000..dc251f5
--- /dev/null
+++ b/gradle.properties
@@ -0,0 +1,15 @@
+# Project-wide Gradle settings.
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+# Specifies the JVM arguments used for the daemon process.
+# The setting is particularly useful for tweaking memory settings.
+org.gradle.jvmargs=-Xmx1536m
+# When configured, Gradle will run in incubating parallel mode.
+# This option should only be used with decoupled projects. More details, visit
+# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
+# org.gradle.parallel=true
+android.useAndroidX=true
+android.enableJetifier=true
\ No newline at end of file
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..f6b961f
--- /dev/null
+++ b/gradle/wrapper/gradle-wrapper.jar
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..70f9027
--- /dev/null
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,6 @@
+#Sat Apr 13 07:44:47 PDT 2019
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.1.1-all.zip
diff --git a/gradlew b/gradlew
new file mode 100755
index 0000000..cccdd3d
--- /dev/null
+++ b/gradlew
@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
new file mode 100644
index 0000000..e95643d
--- /dev/null
+++ b/gradlew.bat
@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off

+@rem ##########################################################################

+@rem

+@rem  Gradle startup script for Windows

+@rem

+@rem ##########################################################################

+

+@rem Set local scope for the variables with windows NT shell

+if "%OS%"=="Windows_NT" setlocal

+

+set DIRNAME=%~dp0

+if "%DIRNAME%" == "" set DIRNAME=.

+set APP_BASE_NAME=%~n0

+set APP_HOME=%DIRNAME%

+

+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.

+set DEFAULT_JVM_OPTS=

+

+@rem Find java.exe

+if defined JAVA_HOME goto findJavaFromJavaHome

+

+set JAVA_EXE=java.exe

+%JAVA_EXE% -version >NUL 2>&1

+if "%ERRORLEVEL%" == "0" goto init

+

+echo.

+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.

+echo.

+echo Please set the JAVA_HOME variable in your environment to match the

+echo location of your Java installation.

+

+goto fail

+

+:findJavaFromJavaHome

+set JAVA_HOME=%JAVA_HOME:"=%

+set JAVA_EXE=%JAVA_HOME%/bin/java.exe

+

+if exist "%JAVA_EXE%" goto init

+

+echo.

+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%

+echo.

+echo Please set the JAVA_HOME variable in your environment to match the

+echo location of your Java installation.

+

+goto fail

+

+:init

+@rem Get command-line arguments, handling Windows variants

+

+if not "%OS%" == "Windows_NT" goto win9xME_args

+

+:win9xME_args

+@rem Slurp the command line arguments.

+set CMD_LINE_ARGS=

+set _SKIP=2

+

+:win9xME_args_slurp

+if "x%~1" == "x" goto execute

+

+set CMD_LINE_ARGS=%*

+

+:execute

+@rem Setup the command line

+

+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar

+

+@rem Execute Gradle

+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%

+

+:end

+@rem End local scope for the variables with windows NT shell

+if "%ERRORLEVEL%"=="0" goto mainEnd

+

+:fail

+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of

+rem the _cmd.exe /c_ return code!

+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1

+exit /b 1

+

+:mainEnd

+if "%OS%"=="Windows_NT" endlocal

+

+:omega

diff --git a/library/.gitignore b/library/.gitignore
new file mode 100644
index 0000000..796b96d
--- /dev/null
+++ b/library/.gitignore
@@ -0,0 +1 @@
+/build
diff --git a/library/build.gradle b/library/build.gradle
new file mode 100644
index 0000000..4e082e6
--- /dev/null
+++ b/library/build.gradle
@@ -0,0 +1,51 @@
+apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-android'
+
+android {
+    compileSdkVersion 28
+
+
+    defaultConfig {
+        minSdkVersion 14
+        targetSdkVersion 28
+        versionCode 1
+        versionName "1.0"
+
+        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+
+    packageBuildConfig false
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    implementation 'androidx.fragment:fragment:1.0.0'
+    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+    testImplementation 'junit:junit:4.12'
+    androidTestImplementation 'com.android.support.test:runner:1.0.2'
+    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+}
+repositories {
+    mavenCentral()
+}
+
+apply plugin: 'maven'
+group = "moe.yuuta.flow"
+version = rootProject.ext.version
+uploadArchives {
+    repositories {
+        mavenDeployer {
+            repository(url: uri('../repo'))
+        }
+    }
+}
\ No newline at end of file
diff --git a/library/proguard-rules.pro b/library/proguard-rules.pro
new file mode 100644
index 0000000..f1b4245
--- /dev/null
+++ b/library/proguard-rules.pro
@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile
diff --git a/library/src/androidTest/java/moe/yuuta/flow/ExampleInstrumentedTest.java b/library/src/androidTest/java/moe/yuuta/flow/ExampleInstrumentedTest.java
new file mode 100644
index 0000000..435e2e8
--- /dev/null
+++ b/library/src/androidTest/java/moe/yuuta/flow/ExampleInstrumentedTest.java
@@ -0,0 +1,26 @@
+package moe.yuuta.flow;
+
+import android.content.Context;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
+ */
+@RunWith(AndroidJUnit4.class)
+public class ExampleInstrumentedTest {
+    @Test
+    public void useAppContext() {
+        // Context of the app under test.
+        Context appContext = InstrumentationRegistry.getInstrumentation().getTargetContext();
+
+        assertEquals("moe.yuuta.flow.test", appContext.getPackageName());
+    }
+}
diff --git a/library/src/main/AndroidManifest.xml b/library/src/main/AndroidManifest.xml
new file mode 100644
index 0000000..f3b86f1
--- /dev/null
+++ b/library/src/main/AndroidManifest.xml
@@ -0,0 +1 @@
+<manifest package="moe.yuuta.flow" />
diff --git a/library/src/main/java/moe/yuuta/flow/FlowFragment.java b/library/src/main/java/moe/yuuta/flow/FlowFragment.java
new file mode 100644
index 0000000..d7d4776
--- /dev/null
+++ b/library/src/main/java/moe/yuuta/flow/FlowFragment.java
@@ -0,0 +1,194 @@
+package moe.yuuta.flow;
+
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.constraintlayout.widget.ConstraintLayout;
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentManager;
+import androidx.fragment.app.FragmentPagerAdapter;
+import androidx.viewpager.widget.ViewPager;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The Host fragment
+ */
+public class FlowFragment extends Fragment implements IFlowFragment, View.OnClickListener {
+    private List<PageFragment> mPages = new ArrayList<>(0);
+    // true: after the view settles, update the UI immediately.
+    private volatile boolean mUIUpdateScheduled;
+
+    private Header mHeader;
+    private ViewPager mPager;
+    private NavigationBar mNav;
+
+    /**
+     * Should only be called once.
+     */
+    public void setPages(@NonNull List<PageFragment> pages) {
+        if (mPages != null && mPages.size() > 0) {
+            throw new IllegalStateException("This method should only be called once. Current size: " + mPages.size());
+        }
+        mPages = pages;
+        // Because this method can be called before setting up the layout, so we need to schedule it until the layout is set up.
+        notifyCurrentFlowInfoUpdated();
+    }
+
+    /**
+     * Update the WHOLE UI.
+     */
+    private void updateUI() {
+        final int currentIndex = mPager.getCurrentItem();
+        final PageFragment currentFragment = mPages.get(currentIndex);
+        if (currentFragment.mInfo == null) {
+            throw new NullPointerException("Info is null");
+        }
+        if (currentFragment.mInfo.getNavigationBarConfig() != null) {
+            mNav.applyInfo(currentFragment.mInfo.getNavigationBarConfig());
+        } else {
+            mNav.applyInfo(new NavigationBarConfig(getString(R.string.flow_nav_bar_next),
+                    getString(R.string.flow_nav_bar_previous),
+                    currentIndex == 0 ? View.GONE : View.VISIBLE,
+                    currentIndex >= (mPages.size() - 1) ? View.GONE : View.VISIBLE,
+                    View.VISIBLE,
+                    this,
+                    this));
+        }
+        mHeader.applyInfo(currentFragment.mInfo.getHeaderConfig());
+    }
+
+    @Override
+    public void onClick(View v) {
+        final int currentIndex = mPager.getCurrentItem();
+        if (v.getId() == R.id.flow_nav_left_button) {
+            if (currentIndex > 0) previousFlow();
+        } else if (v.getId() == R.id.flow_nav_right_button) {
+            if (currentIndex < (mPages.size() - 1)) nextFlow();
+        }
+    }
+
+    @Nullable
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
+        final View view = inflater.inflate(R.layout.fragment_flow, container, false);
+        mHeader = new Header(view.<ConstraintLayout>findViewById(R.id.flow_host_header));
+        mNav = new NavigationBar(view.<ConstraintLayout>findViewById(R.id.flow_host_nav));
+        mPager = view.findViewById(R.id.flow_host_pager);
+        mPager.setAdapter(new FragmentPagerAdapter(getChildFragmentManager()) {
+            @Override
+            public Fragment getItem(int position) {
+                PageFragment fragment = mPages.get(position);
+                return fragment;
+            }
+
+            @Override
+            public int getCount() {
+                return mPages.size();
+            }
+        });
+        mPager.addOnPageChangeListener(mPageListener);
+        getChildFragmentManager().registerFragmentLifecycleCallbacks(mCallback, false);
+        return view;
+    }
+
+    @Override
+    public void onDestroyView() {
+        getChildFragmentManager().unregisterFragmentLifecycleCallbacks(mCallback);
+        mPager.removeOnPageChangeListener(mPageListener);
+        super.onDestroyView();
+    }
+
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+        if (mUIUpdateScheduled) {
+            updateUI();
+            mUIUpdateScheduled = false;
+        }
+    }
+
+    @Override
+    public void notifyCurrentFlowInfoUpdated() {
+        if (getView() != null) {
+            mUIUpdateScheduled = false;
+            updateUI();
+        } else {
+            mUIUpdateScheduled = true;
+        }
+    }
+
+    @Override
+    public void nextFlow() {
+        switchToFlow(mPager.getCurrentItem() + 1);
+    }
+
+    @Override
+    public void previousFlow() {
+        switchToFlow(mPager.getCurrentItem() - 1);
+    }
+
+    @Override
+    public int getFlowCount() {
+        return mPages.size();
+    }
+
+    @Override
+    public void switchToFlow(int index) {
+        mPager.setCurrentItem(index, true);
+    }
+
+    private FragmentManager.FragmentLifecycleCallbacks mCallback = new FragmentManager.FragmentLifecycleCallbacks() {
+        @Override
+        public void onFragmentPreCreated(@NonNull FragmentManager fm, @NonNull Fragment f, @Nullable Bundle savedInstanceState) {
+            if (f instanceof PageFragment) {
+                final PageFragment pf = (PageFragment) f;
+                pf.setHostFragment(FlowFragment.this);
+            }
+        }
+    };
+
+    private ViewPager.OnPageChangeListener mPageListener = new ViewPager.OnPageChangeListener() {
+        @Override
+        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
+
+        }
+
+        @Override
+        public void onPageSelected(int position) {
+            notifyCurrentFlowInfoUpdated();
+        }
+
+        @Override
+        public void onPageScrollStateChanged(int state) {
+
+        }
+    };
+
+    /**
+     * @return true: the fragment handled this event and you do not need to call super. false: call super.
+     */
+    public boolean onBackPressed() {
+        if (getView() == null) return false;
+        if (mPages.size() <= 0) return false;
+        final PageFragment pf = mPages.get(mPager.getCurrentItem());
+        if (pf != null) {
+            if (pf.onBackPressed()) return true;
+        }
+        // Default handling
+        if (mPager.getCurrentItem() == 0) return false;
+        mNav.getButton(NavigationBar.ButtonPosition.LEFT).performClick();
+        return true;
+    }
+
+    @Override
+    @NonNull
+    public View.OnClickListener getGeneralFlowNavListener() {
+        return this;
+    }
+}
diff --git a/library/src/main/java/moe/yuuta/flow/FlowInfo.kt b/library/src/main/java/moe/yuuta/flow/FlowInfo.kt
new file mode 100644
index 0000000..d12228c
--- /dev/null
+++ b/library/src/main/java/moe/yuuta/flow/FlowInfo.kt
@@ -0,0 +1,10 @@
+package moe.yuuta.flow;
+
+/**
+ * Stores basic info, for instance, title and subtitle for the flow. These data will
+ * be auto applied when user switch to the related flow and will be reset after leaving the flow.
+ */
+data class FlowInfo(
+        var headerConfig: HeaderConfig,
+        var navigationBarConfig: NavigationBarConfig?
+)
\ No newline at end of file
diff --git a/library/src/main/java/moe/yuuta/flow/Header.java b/library/src/main/java/moe/yuuta/flow/Header.java
new file mode 100644
index 0000000..42d9124
--- /dev/null
+++ b/library/src/main/java/moe/yuuta/flow/Header.java
@@ -0,0 +1,54 @@
+package moe.yuuta.flow;
+
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ProgressBar;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+
+class Header {
+    public enum WhichView {
+        TITLE,
+        SUBTITLE
+    }
+
+    private ViewGroup mRoot;
+    private TextView mTitle;
+    private TextView mSubtitle;
+    private ProgressBar mProgressBar;
+
+    Header() {}
+
+    Header(@NonNull ViewGroup root) {
+        attach(root);
+    }
+
+    /**
+     * The config will be reset after re-attaching.
+     */
+    void attach(@NonNull ViewGroup root) {
+        mRoot = root;
+        mTitle = mRoot.findViewById(R.id.flow_header_title);
+        mSubtitle = mRoot.findViewById(R.id.flow_header_subtitle);
+        mProgressBar = mRoot.findViewById(R.id.flow_header_progressbar);
+    }
+
+    @NonNull
+    private TextView getText(@NonNull WhichView position) {
+        switch (position) {
+            case TITLE:
+                return mTitle;
+            case SUBTITLE:
+                return mSubtitle;
+            default:
+                throw new IllegalArgumentException("Unexpected position");
+        }
+    }
+
+    void applyInfo(@NonNull HeaderConfig config) {
+        mTitle.setText(config.getTitleText());
+        mSubtitle.setText(config.getSubtitleText());
+        mProgressBar.setVisibility(config.getShowProgressBar() ? View.VISIBLE : View.GONE);
+    }
+}
diff --git a/library/src/main/java/moe/yuuta/flow/HeaderConfig.kt b/library/src/main/java/moe/yuuta/flow/HeaderConfig.kt
new file mode 100644
index 0000000..0133897
--- /dev/null
+++ b/library/src/main/java/moe/yuuta/flow/HeaderConfig.kt
@@ -0,0 +1,7 @@
+package moe.yuuta.flow
+
+class HeaderConfig(
+        var titleText: CharSequence,
+        var subtitleText: CharSequence?,
+        var showProgressBar: Boolean = false
+)
\ No newline at end of file
diff --git a/library/src/main/java/moe/yuuta/flow/IFlowFragment.java b/library/src/main/java/moe/yuuta/flow/IFlowFragment.java
new file mode 100644
index 0000000..79f67f6
--- /dev/null
+++ b/library/src/main/java/moe/yuuta/flow/IFlowFragment.java
@@ -0,0 +1,17 @@
+package moe.yuuta.flow;
+
+import android.view.View;
+
+import androidx.annotation.NonNull;
+
+/**
+ * A bridge which is exposed to {@link PageFragment} for controlling the {@link FlowFragment}
+ */
+public interface IFlowFragment {
+    void notifyCurrentFlowInfoUpdated();
+    void nextFlow();
+    void previousFlow();
+    int getFlowCount();
+    void switchToFlow(int index);
+    @NonNull View.OnClickListener getGeneralFlowNavListener();
+}
diff --git a/library/src/main/java/moe/yuuta/flow/NavigationBar.java b/library/src/main/java/moe/yuuta/flow/NavigationBar.java
new file mode 100644
index 0000000..14fae26
--- /dev/null
+++ b/library/src/main/java/moe/yuuta/flow/NavigationBar.java
@@ -0,0 +1,82 @@
+package moe.yuuta.flow;
+
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Button;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+class NavigationBar {
+    public enum ButtonPosition {
+        LEFT,
+        RIGHT
+    }
+
+    private ViewGroup mRoot;
+    private Button mLeftButton;
+    private Button mRightButton;
+
+    NavigationBar() {}
+
+    NavigationBar(@NonNull ViewGroup navBarRoot) {
+        attach(navBarRoot);
+    }
+
+    /**
+     * The config will be reset after re-attaching.
+     */
+    void attach(@NonNull ViewGroup navBarRoot) {
+        mRoot = navBarRoot;
+        mLeftButton = mRoot.findViewById(R.id.flow_nav_left_button);
+        mRightButton = mRoot.findViewById(R.id.flow_nav_right_button);
+    }
+
+    @NonNull
+    Button getButton(@NonNull ButtonPosition position) {
+        switch (position) {
+            case LEFT:
+                return mLeftButton;
+            case RIGHT:
+                return mRightButton;
+            default:
+                throw new IllegalArgumentException("Unexpected position");
+        }
+    }
+
+    private void setListener(@NonNull ButtonPosition position, @Nullable View.OnClickListener listener) {
+        switch (position) {
+            case LEFT:
+                mLeftButton.setOnClickListener(listener);
+                break;
+            case RIGHT:
+                mRightButton.setOnClickListener(listener);
+                break;
+        }
+    }
+
+    void applyInfo(@NonNull NavigationBarConfig config) {
+        mLeftButton.setText(config.getLeftButtonText());
+        mRightButton.setText(config.getRightButtonText());
+        setNavigationBarVisibility(config.getNavBarVisibility());
+        setButtonVisibility(ButtonPosition.LEFT, config.getLeftButtonVisibility());
+        setButtonVisibility(ButtonPosition.RIGHT, config.getRightButtonVisibility());
+        setListener(ButtonPosition.LEFT, config.getLeftListener());
+        setListener(ButtonPosition.RIGHT, config.getRightListener());
+    }
+
+    private void setNavigationBarVisibility(@View.Visibility int visibility) {
+        mRoot.setVisibility(visibility);
+    }
+
+    private void setButtonVisibility(@NonNull ButtonPosition position, @View.Visibility int visibility) {
+        switch (position) {
+            case LEFT:
+                mLeftButton.setVisibility(visibility);
+                break;
+            case RIGHT:
+                mRightButton.setVisibility(visibility);
+                break;
+        }
+    }
+}
diff --git a/library/src/main/java/moe/yuuta/flow/NavigationBarConfig.kt b/library/src/main/java/moe/yuuta/flow/NavigationBarConfig.kt
new file mode 100644
index 0000000..e027b73
--- /dev/null
+++ b/library/src/main/java/moe/yuuta/flow/NavigationBarConfig.kt
@@ -0,0 +1,16 @@
+package moe.yuuta.flow
+
+import android.view.View
+
+class NavigationBarConfig(
+        var rightButtonText: CharSequence,
+        var leftButtonText: CharSequence,
+        @field:View.Visibility
+        var leftButtonVisibility: Int,
+        @field:View.Visibility
+        var rightButtonVisibility: Int,
+        @field:View.Visibility
+        var navBarVisibility: Int,
+        var leftListener: View.OnClickListener?,
+        var rightListener: View.OnClickListener?
+)
\ No newline at end of file
diff --git a/library/src/main/java/moe/yuuta/flow/PageFragment.java b/library/src/main/java/moe/yuuta/flow/PageFragment.java
new file mode 100644
index 0000000..dcc9f21
--- /dev/null
+++ b/library/src/main/java/moe/yuuta/flow/PageFragment.java
@@ -0,0 +1,30 @@
+package moe.yuuta.flow;
+
+import androidx.annotation.NonNull;
+import androidx.fragment.app.Fragment;
+
+public abstract class PageFragment extends Fragment {
+    private IFlowFragment mHostFragment;
+
+    /**
+     * Once mInfo is changed, you should call {@link IFlowFragment#notifyCurrentFlowInfoUpdated()} to publish it.
+     * Note: it will be permanently change the recorded info.
+     */
+    protected FlowInfo mInfo;
+
+    final void setHostFragment(@NonNull IFlowFragment hostFragment) {
+        this.mHostFragment = hostFragment;
+    }
+
+    @NonNull
+    protected final IFlowFragment getHostFragment() {
+        return mHostFragment;
+    }
+
+    /**
+     * @return true: the fragment handled this event and you do not need to call super. false: call super.
+     */
+    public boolean onBackPressed() {
+        return false;
+    }
+}
\ No newline at end of file
diff --git a/library/src/main/java/moe/yuuta/flow/widgets/FlowPager.java b/library/src/main/java/moe/yuuta/flow/widgets/FlowPager.java
new file mode 100644
index 0000000..c821eef
--- /dev/null
+++ b/library/src/main/java/moe/yuuta/flow/widgets/FlowPager.java
@@ -0,0 +1,64 @@
+package moe.yuuta.flow.widgets;
+
+import android.content.Context;
+import android.os.Build;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import android.view.View;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.FragmentPagerAdapter;
+import androidx.viewpager.widget.ViewPager;
+
+public class FlowPager extends ViewPager {
+    public FlowPager(@NonNull Context context) {
+        super(context);
+    }
+
+    public FlowPager(@NonNull Context context, @Nullable AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    // Thanks to https://stackoverflow.com/a/32488566/6792243
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+
+        if(null != getAdapter()) {
+            int height = 0;
+            View child = ((FragmentPagerAdapter) getAdapter()).getItem(getCurrentItem()).getView();
+            if (child != null) {
+                child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
+                height = child.getMeasuredHeight();
+                // TODO: Support api-14 and api-15?
+                if (Build.VERSION.SDK_INT >= 16 && height < getMinimumHeight()) {
+                    height = getMinimumHeight();
+                }
+            }
+
+            int newHeight = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
+            if (getLayoutParams().height != 0 && heightMeasureSpec != newHeight) {
+                getLayoutParams().height = height;
+
+            } else {
+                heightMeasureSpec = newHeight;
+            }
+        }
+
+        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+    }
+
+    // Thanks to https://stackoverflow.com/a/13437997/6792243
+    @Override
+    public boolean onTouchEvent(MotionEvent event) {
+        return false;
+    }
+
+    // Thanks to https://stackoverflow.com/a/13437997/6792243
+    @Override
+    public boolean onInterceptTouchEvent(MotionEvent event) {
+        return false;
+    }
+
+}
diff --git a/library/src/main/res/layout/fragment_flow.xml b/library/src/main/res/layout/fragment_flow.xml
new file mode 100644
index 0000000..98f6fba
--- /dev/null
+++ b/library/src/main/res/layout/fragment_flow.xml
@@ -0,0 +1,130 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:orientation="vertical"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:id="@id/flow_host_header"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        android:layout_width="match_parent"
+        android:layout_height="0dp">
+        <!-- TODO: firstBaselineToTopHeight compat -->
+        <androidx.constraintlayout.widget.ConstraintLayout
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintEnd_toEndOf="parent">
+            <ProgressBar
+                android:id="@+id/flow_header_progressbar"
+                android:layout_width="0dp"
+                android:layout_height="wrap_content"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toTopOf="parent"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintBottom_toTopOf="@id/flow_header_progressbar_guideline"
+                android:indeterminate="true"
+                android:paddingTop="-4dp"
+                style="?android:attr/progressBarStyleHorizontal"/>
+
+            <androidx.constraintlayout.widget.Guideline
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:id="@id/flow_header_progressbar_guideline"
+                android:orientation="horizontal"
+                app:layout_constraintGuide_begin="2dp" />
+        </androidx.constraintlayout.widget.ConstraintLayout>
+
+        <TextView
+            android:id="@id/flow_header_title"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="64dp"
+            android:textSize="24sp"
+            android:textColor="?android:attr/textColorPrimary"
+            android:layout_gravity="center_horizontal"
+            android:firstBaselineToTopHeight="32dp"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintLeft_toLeftOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintRight_toRightOf="parent"
+            android:textAppearance="?android:attr/textAppearanceLarge"
+            tools:text="Title" />
+
+        <TextView
+            android:id="@id/flow_header_subtitle"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="8dp"
+            android:textSize="16sp"
+            android:textColor="?android:attr/textColorPrimary"
+            android:layout_gravity="center_horizontal"
+            android:firstBaselineToTopHeight="24dp"
+            android:textScaleX="1.1"
+            app:layout_constraintTop_toBottomOf="@id/flow_header_title"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintLeft_toLeftOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintRight_toRightOf="parent"
+            android:textAppearance="?android:attr/textAppearanceMedium"
+            tools:text="Subtitle" />
+    </androidx.constraintlayout.widget.ConstraintLayout>
+
+    <moe.yuuta.flow.widgets.FlowPager
+        android:id="@id/flow_host_pager"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="44dp"
+        app:layout_constraintTop_toBottomOf="@id/flow_host_header"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintRight_toRightOf="parent"/>
+
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:id="@id/flow_host_nav"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="38dp"
+        android:layout_marginStart="44dp"
+        android:layout_marginLeft="44dp"
+        android:layout_marginEnd="44dp"
+        android:layout_marginRight="44dp"
+        app:layout_constraintTop_toBottomOf="@id/flow_host_pager"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        style="?android:attr/buttonBarStyle">
+        <Button
+            android:id="@id/flow_nav_left_button"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintLeft_toLeftOf="parent"
+            tools:text="Back"
+            style="?android:attr/buttonBarButtonStyle"/>
+
+        <Button
+            android:id="@id/flow_nav_right_button"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:layout_constraintRight_toRightOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            tools:text="Next"
+            style="?attr/positiveButtonStyle" />
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
diff --git a/library/src/main/res/values/attrs.xml b/library/src/main/res/values/attrs.xml
new file mode 100644
index 0000000..0e32e81
--- /dev/null
+++ b/library/src/main/res/values/attrs.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <attr name="positiveButtonStyle" format="reference" />
+</resources>
\ No newline at end of file
diff --git a/library/src/main/res/values/ids.xml b/library/src/main/res/values/ids.xml
new file mode 100644
index 0000000..a3117c8
--- /dev/null
+++ b/library/src/main/res/values/ids.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <item name="flow_host_header" type="id" />
+    <item name="flow_host_pager" type="id" />
+    <item name="flow_host_nav" type="id" />
+
+    <item name="flow_nav_left_button" type="id" />
+    <item name="flow_nav_right_button" type="id" />
+
+    <item name="flow_header_title" type="id" />
+    <item name="flow_header_subtitle" type="id" />
+    <item name="flow_header_progressbar" type="id" />
+    <item name="flow_header_progressbar_guideline" type="id" />
+</resources>
\ No newline at end of file
diff --git a/library/src/main/res/values/strings.xml b/library/src/main/res/values/strings.xml
new file mode 100644
index 0000000..ad04d0e
--- /dev/null
+++ b/library/src/main/res/values/strings.xml
@@ -0,0 +1,4 @@
+<resources>
+    <string name="flow_nav_bar_previous">Back</string>
+    <string name="flow_nav_bar_next">Next</string>
+</resources>
diff --git a/library/src/test/java/moe/yuuta/flow/ExampleUnitTest.java b/library/src/test/java/moe/yuuta/flow/ExampleUnitTest.java
new file mode 100644
index 0000000..84848a0
--- /dev/null
+++ b/library/src/test/java/moe/yuuta/flow/ExampleUnitTest.java
@@ -0,0 +1,17 @@
+package moe.yuuta.flow;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
+ */
+public class ExampleUnitTest {
+    @Test
+    public void addition_isCorrect() {
+        assertEquals(4, 2 + 2);
+    }
+}
\ No newline at end of file
diff --git a/settings.gradle b/settings.gradle
new file mode 100644
index 0000000..b0c8eaa
--- /dev/null
+++ b/settings.gradle
@@ -0,0 +1 @@
+include ':app', ':library'
\ No newline at end of file