Merge "[Settings] Avoid to unregister wrong observer" into udc-dev am: 0af8c60342 am: 77e126db56

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/23162866

Change-Id: Ia012c94bca619f1d2165a89908341b2c9aed98d6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

src/com/android/settings/slices/SlicePreferenceController.java

@@ -44,6 +44,7 @@ public class SlicePreferenceController extends BasePreferenceController implemen
     LiveData<Slice> mLiveData;
     @VisibleForTesting
     SlicePreference mSlicePreference;
+    private boolean mIsObservering = false;
     private Uri mUri;
 
     public SlicePreferenceController(Context context, String preferenceKey) {
@@ -68,25 +69,31 @@ public class SlicePreferenceController extends BasePreferenceController implemen
         });
 
         //TODO(b/120803703): figure out why we need to remove observer first
-        mLiveData.removeObserver(this);
+        removeLiveDataObserver();
     }
 
     @Override
     public void onStart() {
-        if (mLiveData != null) {
+        if (mLiveData != null && !mIsObservering) {
+            mIsObservering = true;
             mLiveData.observeForever(this);
         }
     }
 
     @Override
     public void onStop() {
-        if (mLiveData != null) {
-            mLiveData.removeObserver(this);
-        }
+        removeLiveDataObserver();
     }
 
     @Override
     public void onChanged(Slice slice) {
         mSlicePreference.onSliceUpdated(slice);
     }
+
+    private void removeLiveDataObserver() {
+        if (mLiveData != null && mIsObservering && mLiveData.hasActiveObservers()) {
+            mIsObservering = false;
+            mLiveData.removeObserver(this);
+        }
+    }
 }

tests/robotests/src/com/android/settings/slices/SlicePreferenceControllerTest.java

@@ -18,8 +18,10 @@ package com.android.settings.slices;
 
 import static com.google.common.truth.Truth.assertThat;
 
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
 import android.content.Context;
 import android.net.Uri;
@@ -43,11 +45,11 @@ public class SlicePreferenceControllerTest {
     private LiveData<Slice> mLiveData;
     @Mock
     private SlicePreference mSlicePreference;
+
     private Context mContext;
     private SlicePreferenceController mController;
     private Uri mUri;
 
-
     @Before
     public void setUp() {
         MockitoAnnotations.initMocks(this);
@@ -78,10 +80,30 @@ public class SlicePreferenceControllerTest {
 
     @Test
     public void onStop_unregisterObserver() {
+        when(mLiveData.hasActiveObservers()).thenReturn(true);
+        mController.onStart();
+
         mController.onStop();
         verify(mLiveData).removeObserver(mController);
     }
 
+    @Test
+    public void onStop_noActiveObservers_notUnregisterObserver() {
+        when(mLiveData.hasActiveObservers()).thenReturn(false);
+        mController.onStart();
+
+        mController.onStop();
+        verify(mLiveData, never()).removeObserver(mController);
+    }
+
+    @Test
+    public void onStop_notRegisterObserver_notUnregisterObserver() {
+        when(mLiveData.hasActiveObservers()).thenReturn(true);
+
+        mController.onStop();
+        verify(mLiveData, never()).removeObserver(mController);
+    }
+
     @Test
     public void onChanged_nullSlice_updateSlice() {
         mController.onChanged(null);