added scale animation for context menu

chrome/android/java/src/org/chromium/chrome/browser/widget/ContextMenuDialog.java

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.widget;
+
+import android.app.Activity;
+import android.graphics.Color;
+import android.graphics.Rect;
+import android.graphics.drawable.ColorDrawable;
+import android.support.v4.view.animation.LinearOutSlowInInterpolator;
+import android.view.MotionEvent;
+import android.view.View;
+import android.view.View.OnLayoutChangeListener;
+import android.view.ViewGroup;
+import android.view.ViewGroup.LayoutParams;
+import android.view.Window;
+import android.view.animation.Animation;
+import android.view.animation.Animation.AnimationListener;
+import android.view.animation.ScaleAnimation;
+
+import org.chromium.content.browser.RenderCoordinates;
+
+/**
+ * ContextMenuDialog is a subclass of AlwaysDismissedDialog that ensures that the proper scale
+ * animation is played upon calling dismiss().

[Theresa, 2017/05/30 16:16:07]

nit: ... upon calling {@link #show()} and {@link #dismiss()}.

[Daniel Park, 2017/05/30 17:40:40]

Done.

+ */
+public class ContextMenuDialog extends AlwaysDismissedDialog {
+    private static final int ENTER_ANIMATION_DURATION = 250;
+    // Exit animation duration should be set to 60% of the enter animation duration.
+    private static final int EXIT_ANIMATION_DURATION = 150;
+
+    private final Activity mActivity;
+
+    private View mContentView;
+    private float mContextMenuSourceX;
+    private float mContextMenuSourceY;
+    private float mTouchPointX;
+    private float mTouchPointY;
+    private int mContextMenuFirstLocationY;
+    private RenderCoordinates mRenderCoordinates;
+
+    public ContextMenuDialog(Activity ownerActivity, int theme, float touchPointX,
+            float touchPointY, View contentView, RenderCoordinates renderCoordinates) {
+        super(ownerActivity, theme);
+        mActivity = ownerActivity;
+        mTouchPointX = touchPointX;
+        mTouchPointY = touchPointY;
+        mContentView = contentView;
+        mRenderCoordinates = renderCoordinates;
+    }
+
+    @Override
+    public void show() {
+        Window dialogWindow = this.getWindow();
+        dialogWindow.setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
+        dialogWindow.setLayout(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
+
+        mContentView.setVisibility(View.INVISIBLE);
+        mContentView.addOnLayoutChangeListener(new OnLayoutChangeListener() {
+
+            @Override
+            public void onLayoutChange(View v, int left, int top, int right, int bottom,
+                    int oldLeft, int oldTop, int oldRight, int oldBottom) {
+                ViewGroup group = (ViewGroup) v;
+                for (int i = 0; i < group.getChildCount(); i++) {
+                    if (group.getChildAt(i).getHeight() == 0
+                            && group.getChildAt(i).getVisibility() == View.VISIBLE) {
+                        // Return early because not all the views have been measured, so animation
+                        // pivots will be off.
+                        return;
+                    }
+                }
+                mContentView.setVisibility(View.VISIBLE);
+                startEnterAnimation();
+                mContentView.removeOnLayoutChangeListener(this);
+            }
+        });
+        super.show();
+    }
+
+    private void startEnterAnimation() {
+        Rect rectangle = new Rect();
+        Window window = mActivity.getWindow();
+        window.getDecorView().getWindowVisibleDisplayFrame(rectangle);
+
+        float xOffset = rectangle.left;
+        float yOffset = rectangle.top + mRenderCoordinates.getContentOffsetYPix();
+
+        int[] currentLocationOnScreen = new int[2];
+        mContentView.getLocationOnScreen(currentLocationOnScreen);
+
+        mContextMenuFirstLocationY = currentLocationOnScreen[1];
+
+        mContextMenuSourceX = mTouchPointX - currentLocationOnScreen[0] + xOffset;
+        mContextMenuSourceY = mTouchPointY - currentLocationOnScreen[1] + yOffset;
+
+        Animation animation = getScaleAnimation(true, mContextMenuSourceX, mContextMenuSourceY);
+        mContentView.startAnimation(animation);
+    }
+
+    @Override
+    public void dismiss() {
+        int[] contextMenuFinalLocation = new int[2];
+        mContentView.getLocationOnScreen(contextMenuFinalLocation);
+        // Recalculate mContextMenuDestinationY because the context menu's final location may not be
+        // the same as its first location if it changed in height.
+        float contextMenuDestinationY =
+                mContextMenuSourceY + (mContextMenuFirstLocationY - contextMenuFinalLocation[1]);
+
+        Animation exitAnimation =
+                getScaleAnimation(false, mContextMenuSourceX, contextMenuDestinationY);
+        exitAnimation.setAnimationListener(new AnimationListener() {
+
+            @Override
+            public void onAnimationStart(Animation animation) {}
+
+            @Override
+            public void onAnimationRepeat(Animation animation) {}
+
+            @Override
+            public void onAnimationEnd(Animation animation) {
+                ContextMenuDialog.super.dismiss();
+            }
+        });
+        mContentView.startAnimation(exitAnimation);
+    }
+
+    @Override
+    public boolean onTouchEvent(MotionEvent event) {
+        if (event.getAction() == MotionEvent.ACTION_DOWN) {
+            this.dismiss();
+        }
+        return true;

[Theresa, 2017/05/30 16:16:07]

This method should return true if the event was handled and false otherwise, so
this sould probably only return true if the MotionEvent is ACTION_DOWN.

[Daniel Park, 2017/05/30 17:40:40]

Done.

+    }
+
+    /**
+     * @param isEnterAnimation Whether the animation to be returned is for showing the context menu
+     *                         as opposed to hiding it.
+     * @param pivotX The X coordinate of the point about which the object is being scaled, specified
+     *               as an absolute number where 0 is the left edge.
+     * @param pivotY The Y coordinate of the point about which the object is being scaled, specified
+     *               as an absolute number where 0 is the top edge.
+     * @return Returns the scale animation for the context menu.
+     */
+    public Animation getScaleAnimation(boolean isEnterAnimation, float pivotX, float pivotY) {
+        float fromX = isEnterAnimation ? 0f : 1f;
+        float toX = isEnterAnimation ? 1f : 0f;
+        float fromY = fromX;
+        float toY = toX;
+
+        ScaleAnimation animation = new ScaleAnimation(
+                fromX, toX, fromY, toY, Animation.ABSOLUTE, pivotX, Animation.ABSOLUTE, pivotY);
+
+        long duration = isEnterAnimation ? ENTER_ANIMATION_DURATION : EXIT_ANIMATION_DURATION;
+
+        animation.setDuration(duration);
+        animation.setInterpolator(new LinearOutSlowInInterpolator());
+        return animation;
+    }
+}