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 {@link #show()} and {@link #dismiss()}.
+ */
+public class ContextMenuDialog extends AlwaysDismissedDialog {
+    private static final int ENTER_ANIMATION_DURATION = 250;

[Ted C, 2017/05/30 23:04:04]

suffix of _MS to indicate milliseconds

nit, I think we also normally define these as "long"s as that is usually what
animations take.

[Daniel Park, 2017/05/31 18:19:39]

Done.

+    // 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;

[Ted C, 2017/05/30 23:04:04]

same comment about the suffixes of Px or Dp

[Daniel Park, 2017/05/31 18:19:39]

Done.

+    private float mContextMenuSourceY;
+    private float mTouchPointX;
+    private float mTouchPointY;
+    private int mContextMenuFirstLocationY;
+    private RenderCoordinates mRenderCoordinates;
+
+    public ContextMenuDialog(Activity ownerActivity, int theme, float touchPointX,

[Ted C, 2017/05/30 23:04:04]

javadoc

[Daniel Park, 2017/05/31 18:19:39]

Done.

+            float touchPointY, View contentView, RenderCoordinates renderCoordinates) {
+        super(ownerActivity, theme);
+        mActivity = ownerActivity;
+        mTouchPointX = touchPointX;
+        mTouchPointY = touchPointY;
+        mContentView = contentView;
+        mRenderCoordinates = renderCoordinates;

[Ted C, 2017/05/30 23:04:04]

looks like many if not all of these could also be final above?

[Daniel Park, 2017/05/31 18:19:39]

Done.

+    }
+
+    @Override
+    public void show() {
+        Window dialogWindow = this.getWindow();

[Ted C, 2017/05/30 23:04:04]

no need for this.

[Daniel Park, 2017/05/31 18:19:39]

Done.

+        dialogWindow.setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
+        dialogWindow.setLayout(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
+
+        mContentView.setVisibility(View.INVISIBLE);
+        mContentView.addOnLayoutChangeListener(new OnLayoutChangeListener() {
+

[Ted C, 2017/05/30 23:04:04]

remove blank line

[Daniel Park, 2017/05/31 18:19:39]

Done.

+            @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

[Ted C, 2017/05/30 23:04:04]

I think you can use getMeasuredHeight() == 0 here as that is set earlier than
getHeight()

[Daniel Park, 2017/05/31 18:19:39]

Done.

+                            && 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);

[Ted C, 2017/05/30 23:04:04]

you should try this on a phone on a sight with theme colors (facebook.com for
example).  Then rotate in all directions and make sure your starting point is
correct.  Sometimes this will include the android nav bars and not, so it would
be good to ensure this is correct for you always.

[Daniel Park, 2017/05/31 18:19:39]

Done.

[Daniel Park, 2017/05/31 18:19:39]

the starting points are all correct.

+
+        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() {
+

[Ted C, 2017/05/30 23:04:05]

remove blank line

[Daniel Park, 2017/05/31 18:19:39]

Done.

+            @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();

[Ted C, 2017/05/30 23:04:04]

can drop "this."

[Daniel Park, 2017/05/31 18:19:39]

Done.

+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * @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;
+    }
+}