Fix NPE when using VisibilityLogger.

Fix: 31612160
Test: make RunSettingsRoboTests
Change-Id: Ib040a40d27a76d9440f629ed4f768dc4bfde8ac2

src/com/android/settings/DeviceAdminSettings.java

@@ -49,8 +49,8 @@ import android.widget.ListView;
 import android.widget.TextView;
 
 import com.android.internal.logging.MetricsProto;
-import com.android.settings.core.instrumentation.VisibilityLoggerMixin;
 import com.android.settings.core.instrumentation.Instrumentable;
+import com.android.settings.core.instrumentation.VisibilityLoggerMixin;
 
 import org.xmlpull.v1.XmlPullParserException;
 
@@ -84,6 +84,13 @@ public class DeviceAdminSettings extends ListFragment implements Instrumentable
             return this.name.compareTo(other.name);
         }
     }
+
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+        mVisibilityLoggerMixin.onAttach(context);
+    }
+
     /**
      * Internal collection of device admin info objects for all profiles associated with the current
      * user.

src/com/android/settings/UserDictionarySettings.java

@@ -80,6 +80,12 @@ public class UserDictionarySettings extends ListFragment implements Instrumentab
         return MetricsProto.MetricsEvent.USER_DICTIONARY_SETTINGS;
     }
 
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+        mVisibilityLoggerMixin.onAttach(context);
+    }
+
     @Override
     public View onCreateView(
             LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

src/com/android/settings/ZonePicker.java

@@ -136,6 +136,12 @@ public class ZonePicker extends ListFragment implements Instrumentable {
         return TimeZone.getTimeZone((String)((Map<?, ?>)item).get(ZoneGetter.KEY_ID));
     }
 
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
+        mVisibilityLoggerMixin.onAttach(context);
+    }
+
     @Override
     public int getMetricsCategory() {
         return MetricsProto.MetricsEvent.ZONE_PICKER;

src/com/android/settings/core/instrumentation/VisibilityLoggerMixin.java

@@ -50,11 +50,15 @@ public class VisibilityLoggerMixin implements LifecycleObserver, OnResume, OnPau
 
     @Override
     public void onResume() {
+        if (mMetricsFeature != null) {
             mMetricsFeature.visible(null /* context */, mMetricsCategory);
         }
+    }
 
     @Override
     public void onPause() {
+        if (mMetricsFeature != null) {
             mMetricsFeature.hidden(null /* context */, mMetricsCategory);
         }
     }
+}

tests/robotests/src/com/android/settings/core/instrumentation/VisibilityLoggerMixinTest.java

@@ -28,7 +28,9 @@ import org.robolectric.RobolectricTestRunner;
 import org.robolectric.annotation.Config;
 
 import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyInt;
 import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
@@ -51,6 +53,7 @@ public class VisibilityLoggerMixinTest {
     @Test
     public void shouldLogVisibleOnResume() {
         mMixin.onResume();
+
         verify(mMetricsFeature, times(1))
                 .visible(any(Context.class), eq(TestInstrumentable.TEST_METRIC));
     }
@@ -58,10 +61,21 @@ public class VisibilityLoggerMixinTest {
     @Test
     public void shouldLogHideOnPause() {
         mMixin.onPause();
+
         verify(mMetricsFeature, times(1))
                 .hidden(any(Context.class), eq(TestInstrumentable.TEST_METRIC));
     }
 
+    @Test
+    public void shouldNotLogIfMetricsFeatureIsNull() {
+        mMixin = new VisibilityLoggerMixin(TestInstrumentable.TEST_METRIC);
+        mMixin.onResume();
+        mMixin.onPause();
+
+        verify(mMetricsFeature, never())
+                .hidden(any(Context.class), anyInt());
+    }
+
     private final class TestInstrumentable implements Instrumentable {
 
         public static final int TEST_METRIC = 12345;