Add an opacity attribute to LayerDrawable that lets you control the opacity directly instead of

collecting the values from the children-- a task that is much harder to get right than we want to
spend startup time on.

Change-Id: Idf5b1d612472c6accfdc935c6a6fadb1eb239a73

api/current.xml

@@ -6697,6 +6697,17 @@
  visibility="public"
 >
 </field>
+<field name="opacity"
+ type="int"
+ transient="false"
+ volatile="false"
+ value="16843567"
+ static="true"
+ final="true"
+ deprecated="not deprecated"
+ visibility="public"
+>
+</field>
 <field name="order"
  type="int"
  transient="false"
@@ -86062,6 +86073,19 @@
 <parameter name="b" type="int">
 </parameter>
 </method>
+<method name="setOpacity"
+ return="void"
+ abstract="false"
+ native="false"
+ synchronized="false"
+ static="false"
+ final="false"
+ deprecated="not deprecated"
+ visibility="public"
+>
+<parameter name="opacity" type="int">
+</parameter>
+</method>
 <method name="unscheduleDrawable"
  return="void"
  abstract="false"

core/res/res/values/attrs.xml

@@ -49,7 +49,6 @@
              window is floating. -->
         <attr name="backgroundDimEnabled" format="boolean" />
         
-
         <!-- =========== -->
         <!-- Text styles -->
         <!-- =========== -->
@@ -2943,6 +2942,14 @@
         <attr name="bottom" format="dimension" />
     </declare-styleable>
 
+    <declare-styleable name="LayerDrawable">
+        <attr name="opacity">
+            <enum name="opaque" value="-1" />
+            <enum name="transparent" value="-2" />
+            <enum name="translucent" value="-3" />
+        </attr>
+    </declare-styleable>
+
     <declare-styleable name="LayerDrawableItem">
         <attr name="left" />
         <attr name="top" />

core/res/res/values/public.xml

@@ -1378,6 +1378,7 @@
   <public type="attr" name="state_accelerated" />
   <public type="attr" name="baseline" />
   <public type="attr" name="homeLayout" />
+  <public type="attr" name="opacity" />
 
   <public type="anim" name="animator_fade_in" />
   <public type="anim" name="animator_fade_out" />

graphics/java/android/graphics/drawable/LayerDrawable.java

@@ -26,6 +26,7 @@ import android.graphics.ColorFilter;
 import android.graphics.PixelFormat;
 import android.graphics.Rect;
 import android.util.AttributeSet;
+import android.util.Slog;
 import android.view.View;
 
 import java.io.IOException;
@@ -49,6 +50,7 @@ import java.io.IOException;
 public class LayerDrawable extends Drawable implements Drawable.Callback {
     LayerState mLayerState;
 
+    private int mOpacityOverride = PixelFormat.UNKNOWN;
     private int[] mPaddingL;
     private int[] mPaddingT;
     private int[] mPaddingR;
@@ -113,6 +115,13 @@ public class LayerDrawable extends Drawable implements Drawable.Callback {
 
         int type;
 
+        TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.LayerDrawable);
+
+        mOpacityOverride = a.getInt(com.android.internal.R.styleable.LayerDrawable_opacity,
+                PixelFormat.UNKNOWN);
+
+        a.recycle();
+
         final int innerDepth = parser.getDepth() + 1;
         int depth;
         while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
@@ -125,7 +134,7 @@ public class LayerDrawable extends Drawable implements Drawable.Callback {
                 continue;
             }
 
-            TypedArray a = r.obtainAttributes(attrs,
+            a = r.obtainAttributes(attrs,
                     com.android.internal.R.styleable.LayerDrawableItem);
 
             int left = a.getDimensionPixelOffset(
@@ -391,9 +400,28 @@ public class LayerDrawable extends Drawable implements Drawable.Callback {
             array[i].mDrawable.setColorFilter(cf);
         }
     }
+
+    /**
+     * Sets the opacity of this drawable directly, instead of collecting the states from
+     * the layers
+     *
+     * @param opacity The opacity to use, or {@link PixelFormat#UNKNOWN PixelFormat.UNKNOWN}
+     * for the default behavior
+     *
+     * @see PixelFormat#UNKNOWN
+     * @see PixelFormat#TRANSLUCENT
+     * @see PixelFormat#TRANSPARENT
+     * @see PixelFormat#OPAQUE
+     */
+    public void setOpacity(int opacity) {
+        mOpacityOverride = opacity;
+    }
     
     @Override
     public int getOpacity() {
+        if (mOpacityOverride != PixelFormat.UNKNOWN) {
+            return mOpacityOverride;
+        }
         return mLayerState.getOpacity();
     }