ActionProvider API update

* Add ActionProvider#overridesItemVisibility and isVisible.
  These methods allow an ActionProvider to override the
  visibility of a MenuItem that it is bound to. If a MenuItem
  has been explicitly hidden by the application, it will not
  be visible.

* Change MediaRouteActionProvider to not require a MediaRouter
  callback, to avoid extra lifecycle management headaches.

Change-Id: I606fa98b3a6a3e60a953dd024274f9bf9c67acdd

2 files changed, 33 insertions, 19 deletions

diff --git a/core/java/android/app/MediaRouteActionProvider.java b/core/java/android/app/MediaRouteActionProvider.java
index 4860182..b1fc90a 100644
--- a/core/java/android/app/MediaRouteActionProvider.java
+++ b/core/java/android/app/MediaRouteActionProvider.java
@@ -21,7 +21,6 @@ import com.android.internal.app.MediaRouteChooserDialogFragment;
 import android.content.Context;
 import android.content.ContextWrapper;
 import android.media.MediaRouter;
-import android.media.MediaRouter.RouteInfo;
 import android.util.Log;
 import android.view.ActionProvider;
 import android.view.MenuItem;
@@ -35,7 +34,6 @@ public class MediaRouteActionProvider extends ActionProvider {
     private MenuItem mMenuItem;
     private MediaRouteButton mView;
     private int mRouteTypes;
-    private final RouterCallback mRouterCallback = new RouterCallback();
     private View.OnClickListener mExtendedSettingsListener;
 
     public MediaRouteActionProvider(Context context) {
@@ -50,18 +48,10 @@ public class MediaRouteActionProvider extends ActionProvider {
     }
 
     public void setRouteTypes(int types) {
-        if (types == mRouteTypes) {
-            // Already registered; nothing to do.
-            return;
-        }
-        if (mRouteTypes != 0) {
-            mRouter.removeCallback(mRouterCallback);
-        }
         mRouteTypes = types;
         if (mView != null) {
             mView.setRouteTypes(mRouteTypes);
         }
-        mRouter.addCallback(types, mRouterCallback);
     }
 
     @Override
@@ -124,15 +114,13 @@ public class MediaRouteActionProvider extends ActionProvider {
         }
     }
 
-    private class RouterCallback extends MediaRouter.SimpleCallback {
-        @Override
-        public void onRouteAdded(MediaRouter router, RouteInfo info) {
-            mMenuItem.setVisible(mRouter.getRouteCount() > 1);
-        }
+    @Override
+    public boolean overridesItemVisibility() {
+        return true;
+    }
 
-        @Override
-        public void onRouteRemoved(MediaRouter router, RouteInfo info) {
-            mMenuItem.setVisible(mRouter.getRouteCount() > 1);
-        }
+    @Override
+    public boolean isVisible() {
+        return mRouter.getRouteCount() > 1;
     }
 }
diff --git a/core/java/android/view/ActionProvider.java b/core/java/android/view/ActionProvider.java
index fa79d36..af9bf9e 100644
--- a/core/java/android/view/ActionProvider.java
+++ b/core/java/android/view/ActionProvider.java
@@ -96,6 +96,32 @@ public abstract class ActionProvider {
     }
 
     /**
+     * The result of this method determines whether or not {@link #isVisible()} will be used
+     * by the {@link MenuItem} this ActionProvider is bound to help determine its visibility.
+     *
+     * @return true if this ActionProvider overrides the visibility of the MenuItem
+     *         it is bound to, false otherwise. The default implementation returns false.
+     * @see #isVisible()
+     */
+    public boolean overridesItemVisibility() {
+        return false;
+    }
+
+    /**
+     * If {@link #overridesItemVisibility()} returns true, the return value of this method
+     * will help determine the visibility of the {@link MenuItem} this ActionProvider is bound to.
+     *
+     * <p>If the MenuItem's visibility is explicitly set to false by the application,
+     * the MenuItem will not be shown, even if this method returns true.</p>
+     *
+     * @return true if the MenuItem this ActionProvider is bound to is visible, false if
+     *         it is invisible. The default implementation returns true.
+     */
+    public boolean isVisible() {
+        return true;
+    }
+
+    /**
      * Performs an optional default action.
      * <p>
      * For the case of an action provider placed in a menu item not shown as an action this