Fix crash for UiBlockerController

1. Don't create UiBlockerController if there is no related controller
2. Don't update visibility if UiBlockerController is null
3. Use findPreference() from DashboardFragment, which already has null
check.

Change-Id: Iee24c64317fb9d5a1cf2076d25728af485d390c5
Fixes: 122807414
Fixes: 122805831
Test: RunSettingsRoboTests

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

@@ -68,7 +68,8 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
     private DashboardTilePlaceholderPreferenceController mPlaceholderPreferenceController;
     private boolean mListeningToCategoryChange;
     private SummaryLoader mSummaryLoader;
-    private UiBlockerController mBlockerController;
+    @VisibleForTesting
+    UiBlockerController mBlockerController;
 
     @Override
     public void onAttach(Context context) {
@@ -111,7 +112,8 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
         checkUiBlocker(controllers);
     }
 
-    private void checkUiBlocker(List<AbstractPreferenceController> controllers) {
+    @VisibleForTesting
+    void checkUiBlocker(List<AbstractPreferenceController> controllers) {
         final List<String> keys = new ArrayList<>();
         controllers
                 .stream()
@@ -121,8 +123,10 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
                     keys.add(controller.getPreferenceKey());
                 });
 
+        if (!keys.isEmpty()) {
             mBlockerController = new UiBlockerController(keys);
-        mBlockerController.start(()->updatePreferenceVisibility());
+            mBlockerController.start(()->updatePreferenceVisibility(mPreferenceControllers));
+        }
     }
 
     @Override
@@ -355,21 +359,23 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
             activity.reportFullyDrawn();
         }
 
-        updatePreferenceVisibility();
+        updatePreferenceVisibility(mPreferenceControllers);
     }
 
-    private void updatePreferenceVisibility() {
+    @VisibleForTesting
+    void updatePreferenceVisibility(
+            Map<Class, List<AbstractPreferenceController>> preferenceControllers) {
         final PreferenceScreen screen = getPreferenceScreen();
-        if (screen == null) {
+        if (screen == null || preferenceControllers == null || mBlockerController == null) {
             return;
         }
 
         final boolean visible = mBlockerController.isBlockerFinished();
         for (List<AbstractPreferenceController> controllerList :
-                mPreferenceControllers.values()) {
+                preferenceControllers.values()) {
             for (AbstractPreferenceController controller : controllerList) {
                 final String key = controller.getPreferenceKey();
-                final Preference preference = screen.findPreference(key);
+                final Preference preference = findPreference(key);
                 if (preference != null) {
                     preference.setVisible(visible && controller.isAvailable());
                 }

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

@@ -33,7 +33,7 @@ import java.util.concurrent.TimeUnit;
  * Control ui blocker data and check whether it is finished
  *
  * @see BasePreferenceController.UiBlocker
- * @see BasePreferenceController.OnUiBlockListener
+ * @see BasePreferenceController.UiBlockListener
  */
 public class UiBlockerController {
     private static final String TAG = "UiBlockerController";

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

@@ -38,6 +38,7 @@ import androidx.preference.PreferenceScreen;
 
 import com.android.internal.logging.nano.MetricsProto.MetricsEvent;
 import com.android.settings.core.PreferenceControllerMixin;
+import com.android.settings.slices.BlockingSlicePrefController;
 import com.android.settings.testutils.FakeFeatureFactory;
 import com.android.settingslib.core.AbstractPreferenceController;
 import com.android.settingslib.core.instrumentation.MetricsFeatureProvider;
@@ -55,7 +56,10 @@ import org.robolectric.RuntimeEnvironment;
 import org.robolectric.util.ReflectionHelpers;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 @RunWith(RobolectricTestRunner.class)
 public class DashboardFragmentTest {
@@ -66,6 +70,7 @@ public class DashboardFragmentTest {
     private DashboardCategory mDashboardCategory;
     private Context mContext;
     private TestFragment mTestFragment;
+    private List<AbstractPreferenceController> mControllers;
 
     @Before
     public void setUp() {
@@ -83,6 +88,7 @@ public class DashboardFragmentTest {
                 .thenReturn(mDashboardCategory);
         mTestFragment.onAttach(RuntimeEnvironment.application);
         when(mContext.getPackageName()).thenReturn("TestPackage");
+        mControllers = new ArrayList<>();
     }
 
     @Test
@@ -193,6 +199,39 @@ public class DashboardFragmentTest {
                 DASHBOARD_CONTAINER, null, 0);
     }
 
+    @Test
+    public void updatePreferenceVisibility_prefKeyNull_shouldNotCrash() {
+        final Map<Class, List<AbstractPreferenceController>> prefControllers = new HashMap<>();
+        final List<AbstractPreferenceController> controllerList = new ArrayList<>();
+        controllerList.add(new TestPreferenceController(mContext));
+        prefControllers.put(TestPreferenceController.class, controllerList);
+        mTestFragment.mBlockerController = new UiBlockerController(Arrays.asList("pref_key"));
+
+        // Should not crash
+        mTestFragment.updatePreferenceVisibility(prefControllers);
+    }
+
+    @Test
+    public void checkUiBlocker_noUiBlocker_controllerIsNull() {
+        mTestFragment.mBlockerController = null;
+        mControllers.add(new TestPreferenceController(mContext));
+
+        mTestFragment.checkUiBlocker(mControllers);
+
+        assertThat(mTestFragment.mBlockerController).isNull();
+    }
+
+    @Test
+    public void checkUiBlocker_hasUiBlocker_controllerNotNull() {
+        mTestFragment.mBlockerController = null;
+        mControllers.add(new TestPreferenceController(mContext));
+        mControllers.add(new BlockingSlicePrefController(mContext, "pref_key"));
+
+        mTestFragment.checkUiBlocker(mControllers);
+
+        assertThat(mTestFragment.mBlockerController).isNotNull();
+    }
+
     public static class TestPreferenceController extends AbstractPreferenceController
             implements PreferenceControllerMixin {