1 files changed, 163 insertions, 0 deletions
diff --git a/setupwizardlib/src/main/java/com/android/setupwizardlib/view/StickyHeaderListView.java b/setupwizardlib/src/main/java/com/android/setupwizardlib/view/StickyHeaderListView.java
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+++ b/setupwizardlib/src/main/java/com/android/setupwizardlib/view/StickyHeaderListView.java
@@ -0,0 +1,163 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.setupwizardlib.view;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.graphics.Canvas;
+import android.graphics.RectF;
+import android.os.Build;
+import android.util.AttributeSet;
+import android.view.LayoutInflater;
+import android.view.MotionEvent;
+import android.view.View;
+import android.view.WindowInsets;
+import android.view.accessibility.AccessibilityEvent;
+import android.widget.ListView;
+
+import com.android.setupwizardlib.R;
+
+/**
+ * This class provides sticky header functionality in a list view, to use with
+ * SetupWizardIllustration. To use this, add a header tagged with "sticky", or a header tagged with
+ * "stickyContainer" and one of its child tagged as "sticky". The sticky container will be drawn
+ * when the sticky element hits the top of the view.
+ *
+ * <p>There are a few things to note:
+ * <ol>
+ *   <li>The two supported scenarios are StickyHeaderListView -> Header (stickyContainer) -> sticky,
+ *   and StickyHeaderListView -> Header (sticky). The arrow (->) represents parent/child
+ *   relationship and must be immediate child.
+ *   <li>The view does not work well with padding. b/16190933
+ *   <li>If fitsSystemWindows is true, then this will offset the sticking position by the height of
+ *   the system decorations at the top of the screen.
+ * </ol>
+ *
+ * @see StickyHeaderScrollView
+ */
+public class StickyHeaderListView extends ListView {
+
+    private View mSticky;
+    private View mStickyContainer;
+    private int mStatusBarInset = 0;
+    private RectF mStickyRect = new RectF();
+
+    public StickyHeaderListView(Context context) {
+        super(context);
+        init(null, android.R.attr.listViewStyle);
+    }
+
+    public StickyHeaderListView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        init(attrs, android.R.attr.listViewStyle);
+    }
+
+    public StickyHeaderListView(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+        init(attrs, defStyleAttr);
+    }
+
+    private void init(AttributeSet attrs, int defStyleAttr) {
+        final TypedArray a = getContext().obtainStyledAttributes(attrs,
+                R.styleable.SuwStickyHeaderListView, defStyleAttr, 0);
+        int headerResId = a.getResourceId(R.styleable.SuwStickyHeaderListView_suwHeader, 0);
+        if (headerResId != 0) {
+            LayoutInflater inflater = LayoutInflater.from(getContext());
+            View header = inflater.inflate(headerResId, this, false);
+            addHeaderView(header, null, false);
+        }
+        a.recycle();
+    }
+
+    @Override
+    protected void onLayout(boolean changed, int l, int t, int r, int b) {
+        super.onLayout(changed, l, t, r, b);
+        if (mSticky == null) {
+            updateStickyView();
+        }
+    }
+
+    public void updateStickyView() {
+        mSticky = findViewWithTag("sticky");
+        mStickyContainer = findViewWithTag("stickyContainer");
+    }
+
+    @Override
+    public boolean dispatchTouchEvent(MotionEvent ev) {
+        if (mStickyRect.contains(ev.getX(), ev.getY())) {
+            ev.offsetLocation(-mStickyRect.left, -mStickyRect.top);
+            return mStickyContainer.dispatchTouchEvent(ev);
+        } else {
+            return super.dispatchTouchEvent(ev);
+        }
+    }
+
+    @Override
+    public void draw(Canvas canvas) {
+        super.draw(canvas);
+        if (mSticky != null) {
+            final int saveCount = canvas.save();
+            // The view to draw when sticking to the top
+            final View drawTarget = mStickyContainer != null ? mStickyContainer : mSticky;
+            // The offset to draw the view at when sticky
+            final int drawOffset = mStickyContainer != null ? mSticky.getTop() : 0;
+            // Position of the draw target, relative to the outside of the scrollView
+            final int drawTop = drawTarget.getTop();
+            if (drawTop + drawOffset < mStatusBarInset || !drawTarget.isShown()) {
+                // ListView does not translate the canvas, so we can simply draw at the top
+                mStickyRect.set(0, -drawOffset + mStatusBarInset, drawTarget.getWidth(),
+                        drawTarget.getHeight() - drawOffset + mStatusBarInset);
+                canvas.translate(0, mStickyRect.top);
+                canvas.clipRect(0, 0, drawTarget.getWidth(), drawTarget.getHeight());
+                drawTarget.draw(canvas);
+            } else {
+                mStickyRect.setEmpty();
+            }
+            canvas.restoreToCount(saveCount);
+        }
+    }
+
+    @Override
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    public WindowInsets onApplyWindowInsets(WindowInsets insets) {
+        if (getFitsSystemWindows()) {
+            mStatusBarInset = insets.getSystemWindowInsetTop();
+            insets.replaceSystemWindowInsets(
+                    insets.getSystemWindowInsetLeft(),
+                    0, /* top */
+                    insets.getSystemWindowInsetRight(),
+                    insets.getSystemWindowInsetBottom()
+            );
+        }
+        return insets;
+    }
+
+    @Override
+    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
+        super.onInitializeAccessibilityEvent(event);
+
+        // Decoration-only headers should not count as an item for accessibility, adjust the
+        // accessibility event to account for that.
+        final int numberOfHeaders = mSticky != null ? 1 : 0;
+        event.setItemCount(event.getItemCount() - numberOfHeaders);
+        event.setFromIndex(Math.max(event.getFromIndex() - numberOfHeaders, 0));
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
+            event.setToIndex(Math.max(event.getToIndex() - numberOfHeaders, 0));
+        }
+    }
+}