Animating dragview color change when dragging over ButtonDropTarget

Change-Id: I642438be681769812302dba0b6deca38f89f7a16

proguard.flags

@@ -65,4 +65,8 @@
 -keep class com.android.launcher3.AppsContainerRecyclerView {
   public void setFastScrollerAlpha(float);
   public float getFastScrollerAlpha();
-}
+}
+
+-keep class com.android.launcher3.ButtonDropTarget {
+  public int getTextColor();
+}

res/values/config.xml

@@ -55,9 +55,6 @@
     <integer name="config_appsCustomizeDragSlopeThreshold">150</integer>
 
 <!-- Workspace -->
-    <!-- The transition duration for the background of the drop targets -->
-    <integer name="config_dropTargetBgTransitionDuration">0</integer>
-
     <!-- The duration (in ms) of the fade animation on the object outlines, used when
          we are dragging objects around on the home screen. -->
     <integer name="config_dragOutlineFadeTime">900</integer>

src/com/android/launcher3/ButtonDropTarget.java

@@ -16,14 +16,16 @@
 
 package com.android.launcher3;
 
+import android.animation.ObjectAnimator;
+import android.annotation.TargetApi;
 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.Drawable;
 import android.graphics.drawable.TransitionDrawable;
+import android.os.Build;
 import android.util.AttributeSet;
 import android.view.View;
 import android.view.View.OnClickListener;
@@ -42,8 +44,6 @@ public abstract class ButtonDropTarget extends TextView
 
     private static int DRAG_VIEW_DROP_DURATION = 285;
 
-    protected final int mTransitionDuration;
-
     protected Launcher mLauncher;
     private int mBottomDragPadding;
     protected TextView mText;
@@ -58,16 +58,15 @@ public abstract class ButtonDropTarget extends TextView
     protected ColorStateList mOriginalTextColor;
     protected TransitionDrawable mDrawable;
 
+    private ObjectAnimator mCurrentColorAnim;
+
     public ButtonDropTarget(Context context, AttributeSet attrs) {
         this(context, attrs, 0);
     }
 
     public ButtonDropTarget(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
-
-        Resources r = getResources();
-        mTransitionDuration = r.getInteger(R.integer.config_dropTargetBgTransitionDuration);
-        mBottomDragPadding = r.getDimensionPixelSize(R.dimen.drop_target_drag_padding);
+        mBottomDragPadding = getResources().getDimensionPixelSize(R.dimen.drop_target_drag_padding);
     }
 
     @Override
@@ -123,8 +122,13 @@ public abstract class ButtonDropTarget extends TextView
     @Override
     public final void onDragEnter(DragObject d) {
         d.dragView.setColor(mHoverColor);
-        mDrawable.startTransition(mTransitionDuration);
-        setTextColor(mHoverColor);
+        if (Utilities.isLmpOrAbove()) {
+            mDrawable.startTransition(DragView.COLOR_CHANGE_DURATION);
+            animateTextColor(mHoverColor);
+        } else {
+            mDrawable.startTransition(0);
+            setTextColor(mHoverColor);
+        }
     }
 
     @Override
@@ -133,8 +137,23 @@ public abstract class ButtonDropTarget extends TextView
     }
 
     protected void resetHoverColor() {
-        mDrawable.resetTransition();
-        setTextColor(mOriginalTextColor);
+        if (Utilities.isLmpOrAbove()) {
+            mDrawable.reverseTransition(DragView.COLOR_CHANGE_DURATION);
+            animateTextColor(mOriginalTextColor.getDefaultColor());
+        } else {
+            mDrawable.resetTransition();
+            setTextColor(mOriginalTextColor);
+        }
+    }
+
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    private void animateTextColor(int targetColor) {
+        if (mCurrentColorAnim != null) {
+            mCurrentColorAnim.cancel();
+        }
+        mCurrentColorAnim = ObjectAnimator.ofArgb(this, "textColor", targetColor);
+        mCurrentColorAnim.setDuration(DragView.COLOR_CHANGE_DURATION);
+        mCurrentColorAnim.start();
     }
 
     @Override
@@ -152,6 +171,10 @@ public abstract class ButtonDropTarget extends TextView
     public final void onDragStart(DragSource source, Object info, int dragAction) {
         mActive = supportsDrop(source, info);
         mDrawable.resetTransition();
+        if (mCurrentColorAnim != null) {
+            mCurrentColorAnim.cancel();
+            mCurrentColorAnim = null;
+        }
         setTextColor(mOriginalTextColor);
         ((ViewGroup) getParent()).setVisibility(mActive ? View.VISIBLE : View.GONE);
     }
@@ -271,4 +294,8 @@ public abstract class ButtonDropTarget extends TextView
         LauncherAppState.getInstance().getAccessibilityDelegate()
             .handleAccessibleDrop(this, null, getAccessibilityDropConfirmation());
     }
+
+    public int getTextColor() {
+        return getTextColors().getDefaultColor();
+    }
 }

src/com/android/launcher3/DragView.java

@@ -16,22 +16,30 @@
 
 package com.android.launcher3;
 
+import android.animation.FloatArrayEvaluator;
 import android.animation.ValueAnimator;
 import android.animation.ValueAnimator.AnimatorUpdateListener;
+import android.annotation.TargetApi;
 import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.ColorMatrix;
+import android.graphics.ColorMatrixColorFilter;
 import android.graphics.Paint;
 import android.graphics.Point;
-import android.graphics.PorterDuff;
-import android.graphics.PorterDuffColorFilter;
 import android.graphics.Rect;
+import android.os.Build;
 import android.view.View;
 import android.view.animation.DecelerateInterpolator;
 
 import com.android.launcher3.util.Thunk;
 
+import java.util.Arrays;
+
 public class DragView extends View {
+    public static int COLOR_CHANGE_DURATION = 200;
+
     @Thunk static float sDragAlpha = 1f;
 
     private Bitmap mBitmap;
@@ -54,6 +62,9 @@ public class DragView extends View {
     // size.  This is ignored for non-icons.
     private float mIntrinsicIconScale = 1f;
 
+    private float[] mCurrentFilter;
+    private ValueAnimator mFilterAnimator;
+
     /**
      * Construct the drag view.
      * <p>
@@ -229,11 +240,50 @@ public class DragView extends View {
             mPaint = new Paint(Paint.FILTER_BITMAP_FLAG);
         }
         if (color != 0) {
-            mPaint.setColorFilter(new PorterDuffColorFilter(color, PorterDuff.Mode.SRC_ATOP));
+            ColorMatrix m1 = new ColorMatrix();
+            m1.setSaturation(0);
+
+            ColorMatrix m2 = new ColorMatrix();
+            m2.setScale(Color.red(color) / 255f, Color.green(color) / 255f,
+                    Color.blue(color) / 255f, Color.alpha(color) / 255f);
+            m1.postConcat(m2);
+
+            if (Utilities.isLmpOrAbove()) {
+                animateFilterTo(m1.getArray());
+            } else {
+                mPaint.setColorFilter(new ColorMatrixColorFilter(m1));
+                invalidate();
+            }
         } else {
-            mPaint.setColorFilter(null);
+            if (!Utilities.isLmpOrAbove() || mCurrentFilter == null) {
+                mPaint.setColorFilter(null);
+                invalidate();
+            } else {
+                animateFilterTo(new ColorMatrix().getArray());
+            }
         }
-        invalidate();
+    }
+
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    private void animateFilterTo(float[] targetFilter) {
+        float[] oldFilter = mCurrentFilter == null ? new ColorMatrix().getArray() : mCurrentFilter;
+        mCurrentFilter = Arrays.copyOf(oldFilter, oldFilter.length);
+
+        if (mFilterAnimator != null) {
+            mFilterAnimator.cancel();
+        }
+        mFilterAnimator = ValueAnimator.ofObject(new FloatArrayEvaluator(mCurrentFilter),
+                oldFilter, targetFilter);
+        mFilterAnimator.setDuration(COLOR_CHANGE_DURATION);
+        mFilterAnimator.addUpdateListener(new AnimatorUpdateListener() {
+
+            @Override
+            public void onAnimationUpdate(ValueAnimator animation) {
+                mPaint.setColorFilter(new ColorMatrixColorFilter(mCurrentFilter));
+                invalidate();
+            }
+        });
+        mFilterAnimator.start();
     }
 
     public boolean hasDrawn() {
@@ -301,4 +351,3 @@ public class DragView extends View {
         }
     }
 }
-