Merge change 7551 into donut

* changes:
  Add ability to delay messages in Filter based on constraint.  Use this to delay 500ms for delete keys in the search dialog.

core/java/android/app/SuggestionsAdapter.java

@@ -40,6 +40,7 @@ import android.view.ViewGroup;
 import android.widget.ImageView;
 import android.widget.ResourceCursorAdapter;
 import android.widget.TextView;
+import android.widget.Filter;
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
@@ -90,6 +91,12 @@ class SuggestionsAdapter extends ResourceCursorAdapter {
     private final Runnable mStartSpinnerRunnable;
     private final Runnable mStopSpinnerRunnable;
 
+    /**
+     * The amount of time we delay in the filter when the user presses the delete key.
+     * @see Filter#setDelayer(android.widget.Filter.Delayer).
+     */
+    private static final long DELETE_KEY_POST_DELAY = 500L;
+
     public SuggestionsAdapter(Context context, SearchDialog searchDialog, SearchableInfo searchable,
             WeakHashMap<String, Drawable> outsideDrawablesCache, boolean globalSearchMode) {
         super(context,
@@ -119,6 +126,18 @@ class SuggestionsAdapter extends ResourceCursorAdapter {
                 mSearchDialog.setWorking(false);
             }
         };
+
+        // delay 500ms when deleting
+        getFilter().setDelayer(new Filter.Delayer() {
+
+            private int mPreviousLength = 0;
+
+            public long getPostingDelay(CharSequence constraint) {
+                long delay = constraint.length() < mPreviousLength ? DELETE_KEY_POST_DELAY : 0;
+                mPreviousLength = constraint.length();
+                return delay;
+            }
+        });
     }
 
     /**

core/java/android/widget/Filter.java

@@ -46,6 +46,8 @@ public abstract class Filter {
     private Handler mThreadHandler;
     private Handler mResultHandler;
 
+    private Delayer mDelayer;
+
     private final Object mLock = new Object();
 
     /**
@@ -55,6 +57,20 @@ public abstract class Filter {
         mResultHandler = new ResultsHandler();
     }
 
+    /**
+     * Provide an interface that decides how long to delay the message for a given query.  Useful
+     * for heuristics such as posting a delay for the delete key to avoid doing any work while the
+     * user holds down the delete key.
+     *
+     * @param delayer The delayer.
+     * @hide
+     */
+    public void setDelayer(Delayer delayer) {
+        synchronized (mLock) {
+            mDelayer = delayer;
+        }
+    }
+
     /**
      * <p>Starts an asynchronous filtering operation. Calling this method
      * cancels all previous non-executed filtering requests and posts a new
@@ -90,6 +106,8 @@ public abstract class Filter {
                 thread.start();
                 mThreadHandler = new RequestHandler(thread.getLooper());
             }
+
+            final long delay = (mDelayer == null) ? 0 : mDelayer.getPostingDelay(constraint);
             
             Message message = mThreadHandler.obtainMessage(FILTER_TOKEN);
     
@@ -102,7 +120,7 @@ public abstract class Filter {
     
             mThreadHandler.removeMessages(FILTER_TOKEN);
             mThreadHandler.removeMessages(FINISH_TOKEN);
-            mThreadHandler.sendMessage(message);
+            mThreadHandler.sendMessageDelayed(message, delay);
         }
     }
 
@@ -289,4 +307,17 @@ public abstract class Filter {
          */
         FilterResults results;
     }
+
+    /**
+     * @hide
+     */
+    public interface Delayer {
+
+        /**
+         * @param constraint The constraint passed to {@link Filter#filter(CharSequence)}
+         * @return The delay that should be used for
+         *         {@link Handler#sendMessageDelayed(android.os.Message, long)}
+         */
+        long getPostingDelay(CharSequence constraint);
+    }
 }