Fix possible NPE in ActivityPicker.

Bug: 2325451.

This change also improves the UI by returning an empty drawable of the appropriate
size to make sure all labels line up correctly in the list.

src/com/android/settings/ActivityPicker.java

@@ -16,6 +16,7 @@
 
 package com.android.settings;
 
+import android.graphics.ColorFilter;
 import android.util.DisplayMetrics;
 import com.android.internal.app.AlertActivity;
 import com.android.internal.app.AlertController;
@@ -349,6 +350,11 @@ public class ActivityPicker extends AlertActivity implements
             int width = mIconWidth;
             int height = mIconHeight;
 
+            if (icon == null) {
+                return new EmptyDrawable(width, height);
+            }
+            
+            try {
                 if (icon instanceof PaintDrawable) {
                     PaintDrawable painter = (PaintDrawable) icon;
                     painter.setIntrinsicWidth(width);
@@ -410,7 +416,58 @@ public class ActivityPicker extends AlertActivity implements
                     }
                 }
     
+            } catch (Throwable t) {
+                icon = new EmptyDrawable(width, height);
+            }
+
             return icon;
         }
     }
+
+    private static class EmptyDrawable extends Drawable {
+        private final int mWidth;
+        private final int mHeight;
+
+        EmptyDrawable(int width, int height) {
+            mWidth = width;
+            mHeight = height;
+        }
+
+        @Override
+        public int getIntrinsicWidth() {
+            return mWidth;
+        }
+
+        @Override
+        public int getIntrinsicHeight() {
+            return mHeight;
+        }
+
+        @Override
+        public int getMinimumWidth() {
+            return mWidth;
+        }
+
+        @Override
+        public int getMinimumHeight() {
+            return mHeight;
+        }
+
+        @Override
+        public void draw(Canvas canvas) {
+        }
+
+        @Override
+        public void setAlpha(int alpha) {
+        }
+
+        @Override
+        public void setColorFilter(ColorFilter cf) {
+        }
+
+        @Override
+        public int getOpacity() {
+            return PixelFormat.TRANSLUCENT;
+        }
+    }    
 }