Merge "Fallback to Recents when Downloads is not available." into nyc-dev

packages/DocumentsUI/src/com/android/documentsui/BaseActivity.java

@@ -793,7 +793,7 @@ public abstract class BaseActivity extends Activity
 
     private static final class HandleRootsChangedTask
             extends PairedTask<BaseActivity, RootInfo, RootInfo> {
-        DocumentInfo mDownloadsDocument;
+        DocumentInfo mDefaultRootDocument;
 
         public HandleRootsChangedTask(BaseActivity activity) {
             super(activity);
@@ -805,28 +805,36 @@ public abstract class BaseActivity extends Activity
 
             final RootInfo currentRoot = roots[0];
             final Collection<RootInfo> cachedRoots = mOwner.mRoots.getRootsBlocking();
-            RootInfo downloadsRoot = null;
             for (final RootInfo root : cachedRoots) {
-                if (root.isDownloads()) {
-                    downloadsRoot = root;
-                }
                 if (root.getUri().equals(currentRoot.getUri())) {
                     // We don't need to change the current root as the current root was not removed.
                     return null;
                 }
             }
-            assert(downloadsRoot != null);
-            mDownloadsDocument = mOwner.getRootDocumentBlocking(downloadsRoot);
-            return downloadsRoot;
+
+            // Choose the default root.
+            final RootInfo defaultRoot = mOwner.mRoots.getDefaultRootBlocking(mOwner.mState);
+            assert(defaultRoot != null);
+            if (!defaultRoot.isRecents()) {
+                mDefaultRootDocument = mOwner.getRootDocumentBlocking(defaultRoot);
+            }
+            return defaultRoot;
         }
 
         @Override
-        protected void finish(RootInfo downloadsRoot) {
-            if (downloadsRoot != null && mDownloadsDocument != null) {
-                // Clear entire backstack and start in new root
-                mOwner.mState.onRootChanged(downloadsRoot);
-                mOwner.mSearchManager.update(downloadsRoot);
-                mOwner.openContainerDocument(mDownloadsDocument);
+        protected void finish(RootInfo defaultRoot) {
+            if (defaultRoot == null) {
+                return;
+            }
+
+            // Clear entire backstack and start in new root.
+            mOwner.mState.onRootChanged(defaultRoot);
+            mOwner.mSearchManager.update(defaultRoot);
+
+            if (defaultRoot.isRecents()) {
+                mOwner.refreshCurrentRootAndDirectory(AnimationView.ANIM_NONE);
+            } else {
+                mOwner.openContainerDocument(mDefaultRootDocument);
             }
         }
     }

packages/DocumentsUI/src/com/android/documentsui/RootsCache.java

@@ -445,6 +445,18 @@ public class RootsCache {
         mCacheUpdateListener = cacheUpdateListener;
     }
 
+    /**
+     * Returns the default root for the specified state.
+     */
+    public RootInfo getDefaultRootBlocking(State state) {
+        for (RootInfo root : getMatchingRoots(getRootsBlocking(), state)) {
+            if (root.isDownloads()) {
+                return root;
+            }
+        }
+        return mRecentsRoot;
+    }
+
     @VisibleForTesting
     static List<RootInfo> getMatchingRoots(Collection<RootInfo> roots, State state) {
         final List<RootInfo> matching = new ArrayList<>();