Skip "null" string when building advanced button summary

- Also added help string to SoundSettings as a side fix.

Change-Id: Ia81a46c6e199b72b52ae1fa9d996c094193b506c
Fix: 37933524
Test: robotests

src/com/android/settings/dashboard/ProgressiveDisclosureMixin.java

@@ -231,7 +231,7 @@ public class ProgressiveDisclosureMixin implements Preference.OnPreferenceClickL
     /**
      * Add preference to collapsed list.
      */
-    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
+    @VisibleForTesting
     void addToCollapsedList(Preference preference) {
         // Insert preference based on it's order.
         int insertionIndex = Collections.binarySearch(mCollapsedPrefs, preference);
@@ -242,12 +242,12 @@ public class ProgressiveDisclosureMixin implements Preference.OnPreferenceClickL
         updateExpandButtonSummary();
     }
 
-    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
+    @VisibleForTesting
     List<Preference> getCollapsedPrefs() {
         return mCollapsedPrefs;
     }
 
-    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
+    @VisibleForTesting
     void updateExpandButtonSummary() {
         final int size = mCollapsedPrefs.size();
         if (size == 0) {
@@ -257,8 +257,11 @@ public class ProgressiveDisclosureMixin implements Preference.OnPreferenceClickL
         } else {
             CharSequence summary = mCollapsedPrefs.get(0).getTitle();
             for (int i = 1; i < size; i++) {
-                summary = mContext.getString(R.string.join_many_items_middle, summary,
-                        mCollapsedPrefs.get(i).getTitle());
+                final CharSequence nextSummary = mCollapsedPrefs.get(i).getTitle();
+                if (!TextUtils.isEmpty(nextSummary)) {
+                    summary = mContext.getString(R.string.join_many_items_middle, summary,
+                            nextSummary);
+                }
             }
             mExpandButton.setSummary(summary);
         }

src/com/android/settings/notification/SoundSettings.java

@@ -75,6 +75,11 @@ public class SoundSettings extends DashboardFragment {
         }
     }
 
+    @Override
+    protected int getHelpResource() {
+        return R.string.help_url_sound;
+    }
+
     @Override
     public void onPause() {
         super.onPause();

tests/robotests/src/com/android/settings/dashboard/ProgressiveDisclosureTest.java

@@ -25,7 +25,6 @@ import android.support.v7.preference.PreferenceScreen;
 import com.android.settings.R;
 import com.android.settings.SettingsRobolectricTestRunner;
 import com.android.settings.TestConfig;
-import com.android.settings.overlay.FeatureFactory;
 import com.android.settings.testutils.FakeFeatureFactory;
 
 import org.junit.Before;
@@ -58,8 +57,6 @@ public class ProgressiveDisclosureTest {
 
     @Mock(answer = Answers.RETURNS_DEEP_STUBS)
     private Context mContext;
-    @Mock
-    private FakeFeatureFactory mFakeFeatureFactory;
     @Mock(answer = Answers.RETURNS_DEEP_STUBS)
     private PreferenceFragment mPreferenceFragment;
     @Mock
@@ -75,7 +72,6 @@ public class ProgressiveDisclosureTest {
         FakeFeatureFactory.setupForTest(mContext);
         mScreen = mPreferenceFragment.getPreferenceScreen();
         mAppContext = ShadowApplication.getInstance().getApplicationContext();
-        mFakeFeatureFactory = (FakeFeatureFactory) FeatureFactory.getFactory(mContext);
         mMixin = new ProgressiveDisclosureMixin(mAppContext,
                 mPreferenceFragment, false /* keepExpanded */);
         ReflectionHelpers.setField(mMixin, "mExpandButton", mExpandButton);
@@ -314,6 +310,25 @@ public class ProgressiveDisclosureTest {
         verify(mExpandButton).setSummary(null);
     }
 
+    @Test
+    public void updateExpandSummary_doNotIncludeEmptyPrefTitle() {
+        final Preference pref1 = new Preference(mAppContext);
+        pref1.setTitle("1");
+        final Preference pref2 = new Preference(mAppContext);
+        pref2.setTitle(null);
+        final Preference pref3 = new Preference(mAppContext);
+        pref3.setTitle("3");
+        final Preference pref4 = new Preference(mAppContext);
+        pref4.setTitle("");
+
+        mMixin.addToCollapsedList(pref1);
+        mMixin.addToCollapsedList(pref2);
+        mMixin.addToCollapsedList(pref3);
+        mMixin.addToCollapsedList(pref4);
+
+        verify(mExpandButton).setSummary("1, 3");
+    }
+
     @Test
     public void updateExapndSummary_singlePref_expandSummarySameAsPrefTitle() {
         final String TEST = "test";