Fix "Play media to" popup close issue when screen rotate

- Avoid calling getListPreference() in onDialogClose() everytime.
  Due to exception in onDialogClose(). Move preference declaration into if condition.
- Add test case for crash case.

Bug: 119744621
Test: make -j50 RunSettingsRoboTests ROBOTEST_FILTER=UpdatableListPreferenceDialogFragmentTest
Change-Id: Ia20b8289a5863136ea74e02e32b537f6967474e8

src/com/android/settings/widget/UpdatableListPreferenceDialogFragment.java

@@ -84,8 +84,8 @@ public class UpdatableListPreferenceDialogFragment extends PreferenceDialogFragm
 
     @Override
     public void onDialogClosed(boolean positiveResult) {
-        final ListPreference preference = getListPreference();
         if (positiveResult && mClickedDialogEntryIndex >= 0) {
+            final ListPreference preference = getListPreference();
             final String value = mEntryValues[mClickedDialogEntryIndex].toString();
             if (preference.callChangeListener(value)) {
                 preference.setValue(value);
@@ -144,7 +144,8 @@ public class UpdatableListPreferenceDialogFragment extends PreferenceDialogFragm
         return mMetricsCategory;
     }
 
-    private ListPreference getListPreference() {
+    @VisibleForTesting
+    ListPreference getListPreference() {
         return (ListPreference) getPreference();
     }
 

tests/robotests/src/com/android/settings/widget/UpdatableListPreferenceDialogFragmentTest.java

@@ -18,7 +18,9 @@ package com.android.settings.widget;
 
 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 android.content.Context;
 import android.widget.ArrayAdapter;
@@ -31,6 +33,7 @@ import com.android.settings.testutils.shadow.ShadowBluetoothUtils;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.RuntimeEnvironment;
@@ -42,9 +45,10 @@ import java.util.ArrayList;
 @Config(shadows = ShadowBluetoothUtils.class)
 public class UpdatableListPreferenceDialogFragmentTest {
 
-    private Context mContext;
-    private UpdatableListPreferenceDialogFragment mUpdatableListPrefDlgFragment;
     private static final String KEY = "Test_Key";
+    @Mock
+    private UpdatableListPreferenceDialogFragment mUpdatableListPrefDlgFragment;
+    private Context mContext;
     private ArrayAdapter mAdapter;
     private ArrayList<CharSequence> mEntries;
 
@@ -53,8 +57,8 @@ public class UpdatableListPreferenceDialogFragmentTest {
         MockitoAnnotations.initMocks(this);
         mContext = RuntimeEnvironment.application;
 
-        mUpdatableListPrefDlgFragment = UpdatableListPreferenceDialogFragment
+        mUpdatableListPrefDlgFragment = spy(UpdatableListPreferenceDialogFragment
-                .newInstance(KEY, MetricsProto.MetricsEvent.DIALOG_SWITCH_A2DP_DEVICES);
+                .newInstance(KEY, MetricsProto.MetricsEvent.DIALOG_SWITCH_A2DP_DEVICES));
         mEntries = spy(new ArrayList<>());
         mUpdatableListPrefDlgFragment.setEntries(mEntries);
         mUpdatableListPrefDlgFragment.
@@ -87,4 +91,11 @@ public class UpdatableListPreferenceDialogFragmentTest {
 
         assertThat(mUpdatableListPrefDlgFragment.getAdapter().getCount()).isEqualTo(2);
     }
+
+    @Test
+    public void onDialogClosed_emptyPreference() {
+        mUpdatableListPrefDlgFragment.onDialogClosed(false);
+
+        verify(mUpdatableListPrefDlgFragment, never()).getListPreference();
+    }
 }