1 files changed, 194 insertions, 0 deletions
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;
+    }
+}