Adding fling-to-delete.

- Also fixing issue where the drop target icon changes color slower than the text.

Change-Id: I0bfa59da5d202016342f1c3de419ebcafd81ff6f

1 files changed, 182 insertions, 2 deletions

diff --git a/src/com/android/launcher2/DeleteDropTarget.java b/src/com/android/launcher2/DeleteDropTarget.java
index 4621dea85..6f455905f 100644
--- a/src/com/android/launcher2/DeleteDropTarget.java
+++ b/src/com/android/launcher2/DeleteDropTarget.java
@@ -16,24 +16,33 @@
 
 package com.android.launcher2;
 
+import android.animation.TimeInterpolator;
+import android.animation.ValueAnimator;
+import android.animation.ValueAnimator.AnimatorUpdateListener;
 import android.content.Context;
 import android.content.res.ColorStateList;
 import android.content.res.Configuration;
 import android.content.res.Resources;
+import android.graphics.PointF;
 import android.graphics.Rect;
 import android.graphics.drawable.TransitionDrawable;
 import android.util.AttributeSet;
 import android.view.View;
+import android.view.ViewConfiguration;
 import android.view.ViewGroup;
-import android.view.animation.AccelerateInterpolator;
+import android.view.animation.AnimationUtils;
 import android.view.animation.DecelerateInterpolator;
 import android.view.animation.LinearInterpolator;
 
 import com.android.launcher.R;
 
 public class DeleteDropTarget extends ButtonDropTarget {
+    private static int DELETE_ANIMATION_DURATION = 285;
+    private static int MODE_FLING_DELETE_TO_TRASH = 0;
+    private static int MODE_FLING_DELETE_ALONG_VECTOR = 1;
+
+    private final int mFlingDeleteMode = MODE_FLING_DELETE_ALONG_VECTOR;
 
-    private static int DELETE_ANIMATION_DURATION = 300;
     private ColorStateList mOriginalTextColor;
     private TransitionDrawable mUninstallDrawable;
     private TransitionDrawable mRemoveDrawable;
@@ -223,4 +232,175 @@ public class DeleteDropTarget extends ButtonDropTarget {
     public void onDrop(DragObject d) {
         animateToTrashAndCompleteDrop(d);
     }
+
+    /**
+     * Creates an animation from the current drag view to the delete trash icon.
+     */
+    private AnimatorUpdateListener createFlingToTrashAnimatorListener(final DragLayer dragLayer,
+            DragObject d, PointF vel, ViewConfiguration config) {
+        final Rect to = getIconRect(d.dragView.getMeasuredWidth(), d.dragView.getMeasuredHeight(),
+                mCurrentDrawable.getIntrinsicWidth(), mCurrentDrawable.getIntrinsicHeight());
+        final Rect from = new Rect();
+        dragLayer.getViewRectRelativeToSelf(d.dragView, from);
+
+        // Calculate how far along the velocity vector we should put the intermediate point on
+        // the bezier curve
+        float velocity = Math.abs(vel.length());
+        float vp = Math.min(1f, velocity / (config.getScaledMaximumFlingVelocity() / 2f));
+        int offsetY = (int) (-from.top * vp);
+        int offsetX = (int) (offsetY / (vel.y / vel.x));
+        final float y2 = from.top + offsetY;                        // intermediate t/l
+        final float x2 = from.left + offsetX;
+        final float x1 = from.left;                                 // drag view t/l
+        final float y1 = from.top;
+        final float x3 = to.left;                                   // delete target t/l
+        final float y3 = to.top;
+
+        final TimeInterpolator scaleAlphaInterpolator = new TimeInterpolator() {
+            @Override
+            public float getInterpolation(float t) {
+                return t * t * t * t * t * t * t * t;
+            }
+        };
+        return new AnimatorUpdateListener() {
+            @Override
+            public void onAnimationUpdate(ValueAnimator animation) {
+                final DragView dragView = (DragView) dragLayer.getAnimatedView();
+                float t = ((Float) animation.getAnimatedValue()).floatValue();
+                float tp = scaleAlphaInterpolator.getInterpolation(t);
+                float initialScale = dragView.getInitialScale();
+                float finalAlpha = 0.5f;
+                float scale = dragView.getScaleX();
+                float x1o = ((1f - scale) * dragView.getMeasuredWidth()) / 2f;
+                float y1o = ((1f - scale) * dragView.getMeasuredHeight()) / 2f;
+                float x = (1f - t) * (1f - t) * (x1 - x1o) + 2 * (1f - t) * t * (x2 - x1o) +
+                        (t * t) * x3;
+                float y = (1f - t) * (1f - t) * (y1 - y1o) + 2 * (1f - t) * t * (y2 - x1o) +
+                        (t * t) * y3;
+
+                dragView.setTranslationX(x);
+                dragView.setTranslationY(y);
+                dragView.setScaleX(initialScale * (1f - tp));
+                dragView.setScaleY(initialScale * (1f - tp));
+                dragView.setAlpha(finalAlpha + (1f - finalAlpha) * (1f - tp));
+            }
+        };
+    }
+
+    /**
+     * Creates an animation from the current drag view along its current velocity vector.
+     * For this animation, the alpha runs for a fixed duration and we update the position
+     * progressively.
+     */
+    private static class FlingAlongVectorAnimatorUpdateListener implements AnimatorUpdateListener {
+        private static float FRICTION = 0.93f;
+
+        private DragLayer mDragLayer;
+        private PointF mVelocity;
+        private Rect mFrom;
+        private long mPrevTime;
+        private boolean mHasOffsetForScale;
+
+        private final TimeInterpolator mAlphaInterpolator = new DecelerateInterpolator(1.5f);
+
+        public FlingAlongVectorAnimatorUpdateListener(DragLayer dragLayer, PointF vel, Rect from,
+                long startTime) {
+            mDragLayer = dragLayer;
+            mVelocity = vel;
+            mFrom = from;
+            mPrevTime = startTime;
+        }
+
+        @Override
+        public void onAnimationUpdate(ValueAnimator animation) {
+            final DragView dragView = (DragView) mDragLayer.getAnimatedView();
+            float t = ((Float) animation.getAnimatedValue()).floatValue();
+            long curTime = AnimationUtils.currentAnimationTimeMillis();
+
+            if (!mHasOffsetForScale) {
+                mHasOffsetForScale = true;
+                float scale = dragView.getScaleX();
+                float xOffset = ((scale - 1f) * dragView.getMeasuredWidth()) / 2f;
+                float yOffset = ((scale - 1f) * dragView.getMeasuredHeight()) / 2f;
+
+                mFrom.left += xOffset;
+                mFrom.top += yOffset;
+            }
+
+            mFrom.left += (mVelocity.x * (curTime - mPrevTime) / 1000f);
+            mFrom.top += (mVelocity.y * (curTime - mPrevTime) / 1000f);
+
+            dragView.setTranslationX(mFrom.left);
+            dragView.setTranslationY(mFrom.top);
+            dragView.setAlpha(1f - mAlphaInterpolator.getInterpolation(t));
+
+            mVelocity.x *= FRICTION;
+            mVelocity.y *= FRICTION;
+            mPrevTime = curTime;
+        }
+    };
+    private AnimatorUpdateListener createFlingAlongVectorAnimatorListener(final DragLayer dragLayer,
+            DragObject d, PointF vel, final long startTime, final int duration,
+            ViewConfiguration config) {
+        final Rect from = new Rect();
+        dragLayer.getViewRectRelativeToSelf(d.dragView, from);
+
+        return new FlingAlongVectorAnimatorUpdateListener(dragLayer, vel, from, startTime);
+    }
+
+    public void onFlingToDelete(final DragObject d, int x, int y, PointF vel) {
+        // Don't highlight the icon as it's animating
+        d.dragView.setColor(0);
+        d.dragView.updateInitialScaleToCurrentScale();
+
+        if (mFlingDeleteMode == MODE_FLING_DELETE_TO_TRASH) {
+            // Defer animating out the drop target if we are animating to it
+            mSearchDropTargetBar.deferOnDragEnd();
+            mSearchDropTargetBar.finishAnimations();
+        }
+
+        final ViewConfiguration config = ViewConfiguration.get(mLauncher);
+        final DragLayer dragLayer = mLauncher.getDragLayer();
+        final int duration = DELETE_ANIMATION_DURATION;
+        final long startTime = AnimationUtils.currentAnimationTimeMillis();
+
+        // NOTE: Because it takes time for the first frame of animation to actually be
+        // called and we expect the animation to be a continuation of the fling, we have
+        // to account for the time that has elapsed since the fling finished.  And since
+        // we don't have a startDelay, we will always get call to update when we call
+        // start() (which we want to ignore).
+        final TimeInterpolator tInterpolator = new TimeInterpolator() {
+            private int mCount = -1;
+            private float mOffset = 0f;
+
+            @Override
+            public float getInterpolation(float t) {
+                if (mCount < 0) {
+                    mCount++;
+                } else if (mCount == 0) {
+                    mOffset = Math.min(0.5f, (float) (AnimationUtils.currentAnimationTimeMillis() -
+                            startTime) / duration);
+                    mCount++;
+                }
+                return Math.min(1f, mOffset + t);
+            }
+        };
+        AnimatorUpdateListener updateCb = null;
+        if (mFlingDeleteMode == MODE_FLING_DELETE_TO_TRASH) {
+            updateCb = createFlingToTrashAnimatorListener(dragLayer, d, vel, config);
+        } else if (mFlingDeleteMode == MODE_FLING_DELETE_ALONG_VECTOR) {
+            updateCb = createFlingAlongVectorAnimatorListener(dragLayer, d, vel, startTime,
+                    duration, config);
+        }
+        Runnable onAnimationEndRunnable = new Runnable() {
+            @Override
+            public void run() {
+                mSearchDropTargetBar.onDragEnd();
+                mLauncher.exitSpringLoadedDragMode();
+                completeDrop(d);
+            }
+        };
+        dragLayer.animateView(d.dragView, updateCb, duration, tInterpolator, onAnimationEndRunnable,
+                DragLayer.ANIMATION_END_DISAPPEAR, null);
+    }
 }