Tweak dialpad opacity animation.

- Do opacity transition individually on keys. This is done with
layer to improve performance.
- Remove opacity transition on the whole dialpad view.
- Remove hide animation entirely.

Bug: 14471388
Change-Id: Ic91e9fa3aeae2933dcc24b1266b9f60df021552d
diff --git a/src/com/android/contacts/common/dialpad/DialpadView.java b/src/com/android/contacts/common/dialpad/DialpadView.java
index 403663d..4efa024 100644
--- a/src/com/android/contacts/common/dialpad/DialpadView.java
+++ b/src/com/android/contacts/common/dialpad/DialpadView.java
@@ -164,20 +164,15 @@
         for (int i = 0; i < mButtonIds.length; i++) {
             dialpadKey = (DialpadKeyButton) findViewById(mButtonIds[i]);
             dialpadKey.setTranslationY(translateDistance);
+            dialpadKey.setAlpha(0);
             dialpadKey.animate()
+                    .withLayer()
                     .translationY(0)
+                    .alpha(1.0f)
                     .setInterpolator(mButtonPathInterpolator)
                     .setStartDelay(getKeyButtonAnimationDelay(mButtonIds[i]))
                     .setDuration(getKeyButtonAnimationDuration(mButtonIds[i]));
         }
-
-        setAlpha(0);
-        animate().alpha(1.0f).setDuration(KEY_FRAME_DURATION * 20);
-    }
-
-    public void animateHide() {
-        setAlpha(1.0f);
-        animate().alpha(0).setDuration(KEY_FRAME_DURATION * 13);
     }
 
     public EditText getDigits() {