Merge "Adds reuse Rect constructor for RectEvaluator."

api/current.txt

@@ -2549,6 +2549,7 @@ package android.animation {
 
   public class RectEvaluator implements android.animation.TypeEvaluator {
     ctor public RectEvaluator();
+    ctor public RectEvaluator(android.graphics.Rect);
     method public android.graphics.Rect evaluate(float, android.graphics.Rect, android.graphics.Rect);
   }
 

core/java/android/animation/RectEvaluator.java

@@ -22,6 +22,35 @@ import android.graphics.Rect;
  */
 public class RectEvaluator implements TypeEvaluator<Rect> {
 
+    /**
+     * When null, a new Rect is returned on every evaluate call. When non-null,
+     * mRect will be modified and returned on every evaluate.
+     */
+    private Rect mRect;
+
+    /**
+     * Construct a RectEvaluator that returns a new Rect on every evaluate call.
+     * To avoid creating an object for each evaluate call,
+     * {@link RectEvaluator#RectEvaluator(android.graphics.Rect)} should be used
+     * whenever possible.
+     */
+    public RectEvaluator() {
+    }
+
+    /**
+     * Constructs a RectEvaluator that modifies and returns <code>reuseRect</code>
+     * in {@link #evaluate(float, android.graphics.Rect, android.graphics.Rect)} calls.
+     * The value returned from
+     * {@link #evaluate(float, android.graphics.Rect, android.graphics.Rect)} should
+     * not be cached because it will change over time as the object is reused on each
+     * call.
+     *
+     * @param reuseRect A Rect to be modified and returned by evaluate.
+     */
+    public RectEvaluator(Rect reuseRect) {
+        mRect = reuseRect;
+    }
+
     /**
      * This function returns the result of linearly interpolating the start and
      * end Rect values, with <code>fraction</code> representing the proportion
@@ -29,6 +58,10 @@ public class RectEvaluator implements TypeEvaluator<Rect> {
      * calculation on each of the separate components in the Rect objects
      * (left, top, right, and bottom).
      *
+     * <p>If {@link #RectEvaluator(android.graphics.Rect)} was used to construct
+     * this RectEvaluator, the object returned will be the <code>reuseRect</code>
+     * passed into the constructor.</p>
+     *
      * @param fraction   The fraction from the starting to the ending values
      * @param startValue The start Rect
      * @param endValue   The end Rect
@@ -37,9 +70,15 @@ public class RectEvaluator implements TypeEvaluator<Rect> {
      */
     @Override
     public Rect evaluate(float fraction, Rect startValue, Rect endValue) {
-        return new Rect(startValue.left + (int)((endValue.left - startValue.left) * fraction),
-                startValue.top + (int)((endValue.top - startValue.top) * fraction),
-                startValue.right + (int)((endValue.right - startValue.right) * fraction),
-                startValue.bottom + (int)((endValue.bottom - startValue.bottom) * fraction));
+        int left = startValue.left + (int) ((endValue.left - startValue.left) * fraction);
+        int top = startValue.top + (int) ((endValue.top - startValue.top) * fraction);
+        int right = startValue.right + (int) ((endValue.right - startValue.right) * fraction);
+        int bottom = startValue.bottom + (int) ((endValue.bottom - startValue.bottom) * fraction);
+        if (mRect == null) {
+            return new Rect(left, top, right, bottom);
+        } else {
+            mRect.set(left, top, right, bottom);
+            return mRect;
+        }
     }
 }