Add new fade in/out feature for drawable containers.

This is used to allow list view's pressed and activated indicators
to fade in an out, though of course it can be used elsewhere as well.

There is a lot of complexity in supporting this in list view.  The
two main things that are being dealt with:

- When recycling views, we need to make sure that the view's drawable
  state doesn't get animated from an old row's state.  The recycler
  now keeps track of which position a view was last in, and if it is
  reused at a new position there is a new View/Drawable API to tell
  it to jump to its current state instead of animating.

- For the pressed indicator to fade out, we need to keep displaying it
  after it is hidden.  There are new variables and code to keep track
  of this state, and tweaks in various places to be able to remember
  the last selected position and continue updating the drawable bounds
  as needed.

Change-Id: Ic96aa1a3c05e519665abf3098892ff2cc4f0ef2f

10 files changed, 22 insertions, 8 deletions

diff --git a/core/res/res/drawable/activated_background.xml b/core/res/res/drawable/activated_background.xml
index d92fba1..1047e5b 100644
--- a/core/res/res/drawable/activated_background.xml
+++ b/core/res/res/drawable/activated_background.xml
@@ -14,7 +14,8 @@
      limitations under the License.
 -->
 
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:exitFadeDuration="@android:integer/config_mediumAnimTime">
     <item android:state_activated="true" android:drawable="@android:drawable/list_selector_background_selected" />
     <item android:drawable="@color/transparent" />
 </selector>
diff --git a/core/res/res/drawable/activated_background_holo_dark.xml b/core/res/res/drawable/activated_background_holo_dark.xml
index febf2c4..a29bcb9 100644
--- a/core/res/res/drawable/activated_background_holo_dark.xml
+++ b/core/res/res/drawable/activated_background_holo_dark.xml
@@ -14,7 +14,8 @@
      limitations under the License.
 -->
 
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:exitFadeDuration="@android:integer/config_mediumAnimTime">
     <item android:state_activated="true" android:drawable="@android:drawable/list_activated_holo" />
     <item android:drawable="@color/transparent" />
 </selector>
diff --git a/core/res/res/drawable/activated_background_holo_light.xml b/core/res/res/drawable/activated_background_holo_light.xml
index febf2c4..a29bcb9 100644
--- a/core/res/res/drawable/activated_background_holo_light.xml
+++ b/core/res/res/drawable/activated_background_holo_light.xml
@@ -14,7 +14,8 @@
      limitations under the License.
 -->
 
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:exitFadeDuration="@android:integer/config_mediumAnimTime">
     <item android:state_activated="true" android:drawable="@android:drawable/list_activated_holo" />
     <item android:drawable="@color/transparent" />
 </selector>
diff --git a/core/res/res/drawable/activated_background_light.xml b/core/res/res/drawable/activated_background_light.xml
index 5d5681d..7d737db 100644
--- a/core/res/res/drawable/activated_background_light.xml
+++ b/core/res/res/drawable/activated_background_light.xml
@@ -14,7 +14,8 @@
      limitations under the License.
 -->
 
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:exitFadeDuration="@android:integer/config_mediumAnimTime">
     <item android:state_activated="true" android:drawable="@drawable/list_selector_background_selected_light" />
     <item android:drawable="@color/transparent" />
 </selector>
diff --git a/core/res/res/drawable/list_selector_background.xml b/core/res/res/drawable/list_selector_background.xml
index 6fb0661..f5eb12d 100644
--- a/core/res/res/drawable/list_selector_background.xml
+++ b/core/res/res/drawable/list_selector_background.xml
@@ -14,7 +14,8 @@
      limitations under the License.
 -->
 
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:exitFadeDuration="@android:integer/config_mediumAnimTime">
 
     <item android:state_window_focused="false" android:drawable="@color/transparent" />
 
diff --git a/core/res/res/drawable/list_selector_background_light.xml b/core/res/res/drawable/list_selector_background_light.xml
index 4da7e21..50a821b 100644
--- a/core/res/res/drawable/list_selector_background_light.xml
+++ b/core/res/res/drawable/list_selector_background_light.xml
@@ -14,7 +14,8 @@
      limitations under the License.
 -->
 
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:exitFadeDuration="@android:integer/config_mediumAnimTime">
 
     <item android:state_window_focused="false" android:drawable="@color/transparent" />
 
diff --git a/core/res/res/drawable/list_selector_holo_dark.xml b/core/res/res/drawable/list_selector_holo_dark.xml
index e4c5c52..9a6cb89 100644
--- a/core/res/res/drawable/list_selector_holo_dark.xml
+++ b/core/res/res/drawable/list_selector_holo_dark.xml
@@ -14,7 +14,8 @@
      limitations under the License.
 -->
 
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:exitFadeDuration="@android:integer/config_mediumAnimTime">
 
     <item android:state_window_focused="false" android:drawable="@color/transparent" />
 
diff --git a/core/res/res/drawable/list_selector_holo_light.xml b/core/res/res/drawable/list_selector_holo_light.xml
index 17631bd..844259e 100644
--- a/core/res/res/drawable/list_selector_holo_light.xml
+++ b/core/res/res/drawable/list_selector_holo_light.xml
@@ -14,7 +14,8 @@
      limitations under the License.
 -->
 
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:exitFadeDuration="@android:integer/config_mediumAnimTime">
 
     <item android:state_window_focused="false" android:drawable="@color/transparent" />
 
diff --git a/core/res/res/values/attrs.xml b/core/res/res/values/attrs.xml
index a2fa1a3..1083452 100755
--- a/core/res/res/values/attrs.xml
+++ b/core/res/res/values/attrs.xml
@@ -2786,6 +2786,10 @@
              same pixel configuration as the screen (for instance: a ARGB 8888 bitmap with
              an RGB 565 screen). -->
         <attr name="dither" format="boolean" />
+        <!-- Amount of time (in milliseconds) to fade in a new state drawable. -->
+        <attr name="enterFadeDuration" format="integer" />
+        <!-- Amount of time (in milliseconds) to fade out an old state drawable. -->
+        <attr name="exitFadeDuration" format="integer" />
     </declare-styleable>
 
     <declare-styleable name="AnimationDrawable">
diff --git a/core/res/res/values/public.xml b/core/res/res/values/public.xml
index fd7e984..f8752d3 100644
--- a/core/res/res/values/public.xml
+++ b/core/res/res/values/public.xml
@@ -1358,6 +1358,8 @@
   <public type="attr" name="buttonGroupStyle" />
   <public type="attr" name="alertDialogButtonGroupStyle" />
   <public type="attr" name="homeAsUpIndicator" />
+  <public type="attr" name="enterFadeDuration" />
+  <public type="attr" name="exitFadeDuration" />
 
   <public type="anim" name="animator_fade_in" />
   <public type="anim" name="animator_fade_out" />