Fix a bug where no URL means refresh never ends

This patch does two things:
- If there is no URL to download new data from, then the
Refresh button is not shown.
- Even if for some reason refresh starts for a client for
which there is no URL, loading correctly finishes.

Bug: 9388602
Change-Id: I3fd9214da50faa4b59d0bd3e775293dd34f07547

java/src/com/android/inputmethod/dictionarypack/DictionaryService.java

@@ -170,7 +170,7 @@ public final class DictionaryService extends Service {
             checkTimeAndMaybeSetupUpdateAlarm(context);
         } else if (DictionaryPackConstants.UPDATE_NOW_INTENT_ACTION.equals(intent.getAction())) {
             // Intent to trigger an update now.
-            UpdateHandler.update(context, false);
+            UpdateHandler.tryUpdate(context, false);
         } else {
             UpdateHandler.downloadFinished(context, intent);
         }
@@ -221,7 +221,7 @@ public final class DictionaryService extends Service {
      */
     public static void updateNowIfNotUpdatedInAVeryLongTime(final Context context) {
         if (!isLastUpdateAtLeastThisOld(context, VERY_LONG_TIME)) return;
-        UpdateHandler.update(context, false);
+        UpdateHandler.tryUpdate(context, false);
     }
 
     /**

java/src/com/android/inputmethod/dictionarypack/DictionarySettingsFragment.java

@@ -30,6 +30,7 @@ import android.os.Bundle;
 import android.preference.Preference;
 import android.preference.PreferenceFragment;
 import android.preference.PreferenceGroup;
+import android.text.TextUtils;
 import android.text.format.DateUtils;
 import android.util.Log;
 import android.view.animation.AnimationUtils;
@@ -104,10 +105,17 @@ public final class DictionarySettingsFragment extends PreferenceFragment
 
     @Override
     public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
-        mUpdateNowMenu = menu.add(Menu.NONE, MENU_UPDATE_NOW, 0, R.string.check_for_updates_now);
+        final String metadataUri =
+                MetadataDbHelper.getMetadataUriAsString(getActivity(), mClientId);
+        // We only add the "Refresh" button if we have a non-empty URL to refresh from. If the
+        // URL is empty, of course we can't refresh so it makes no sense to display this.
+        if (!TextUtils.isEmpty(metadataUri)) {
+            mUpdateNowMenu =
+                    menu.add(Menu.NONE, MENU_UPDATE_NOW, 0, R.string.check_for_updates_now);
             mUpdateNowMenu.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
             refreshNetworkState();
         }
+    }
 
     @Override
     public void onResume() {
@@ -353,7 +361,12 @@ public final class DictionarySettingsFragment extends PreferenceFragment
         new Thread("updateByHand") {
             @Override
             public void run() {
-                UpdateHandler.update(activity, true);
+                // We call tryUpdate(), which returns whether we could successfully start an update.
+                // If we couldn't, we'll never receive the end callback, so we stop the loading
+                // animation and return to the previous screen.
+                if (!UpdateHandler.tryUpdate(activity, true)) {
+                    stopLoadingAnimation();
+                }
             }
         }.start();
     }
@@ -368,7 +381,9 @@ public final class DictionarySettingsFragment extends PreferenceFragment
     private void startLoadingAnimation() {
         mLoadingView.setVisibility(View.VISIBLE);
         getView().setVisibility(View.GONE);
-        mUpdateNowMenu.setTitle(R.string.cancel);
+        // We come here when the menu element is pressed so presumably it can't be null. But
+        // better safe than sorry.
+        if (null != mUpdateNowMenu) mUpdateNowMenu.setTitle(R.string.cancel);
     }
 
     private void stopLoadingAnimation() {

java/src/com/android/inputmethod/dictionarypack/UpdateHandler.java

@@ -173,14 +173,15 @@ public final class UpdateHandler {
      * Download latest metadata from the server through DownloadManager for all known clients
      * @param context The context for retrieving resources
      * @param updateNow Whether we should update NOW, or respect bandwidth policies
+     * @return true if an update successfully started, false otherwise.
      */
-    public static void update(final Context context, final boolean updateNow) {
+    public static boolean tryUpdate(final Context context, final boolean updateNow) {
         // TODO: loop through all clients instead of only doing the default one.
         final TreeSet<String> uris = new TreeSet<String>();
         final Cursor cursor = MetadataDbHelper.queryClientIds(context);
-        if (null == cursor) return;
+        if (null == cursor) return false;
         try {
-            if (!cursor.moveToFirst()) return;
+            if (!cursor.moveToFirst()) return false;
             do {
                 final String clientId = cursor.getString(0);
                 final String metadataUri =
@@ -192,6 +193,7 @@ public final class UpdateHandler {
         } finally {
             cursor.close();
         }
+        boolean started = false;
         for (final String metadataUri : uris) {
             if (!TextUtils.isEmpty(metadataUri)) {
                 // If the metadata URI is empty, that means we should never update it at all.
@@ -200,8 +202,10 @@ public final class UpdateHandler {
                 // is a bug and it happens anyway, doing nothing is the right thing to do.
                 // For more information, {@see DictionaryProvider#insert(Uri, ContentValues)}.
                 updateClientsWithMetadataUri(context, updateNow, metadataUri);
+                started = true;
             }
         }
+        return started;
     }
 
     /**