Fix Conversation page flickers

In this page, 3 conversation lists are implemented by the
ConversationListPreferenceController, these lists updates its contents
in updateState(), which is after the preference screen view created.
So when the first time this page is showed, animations of added contents
will be shown.

The improvement is when the first time, update the list in the
onCreate(), which is called before view creation, instead of the
updateState().

And also do the same thing for RecentConversationsPreferenceController.

Also, to reduce latency,
1. Because currently there are duplicated calls in
NoConversationsPreferenceController to check whether conversations are
exists or not, by removing the duplicated calls and reuse the result
from other controllers, the latency could be reduced.
2. Currently, there are seperated api calls, the
mBackend.getConversations(false) in AllConversationsPreferenceController
and the mBackend.getConversations(true) in
PriorityConversationsPreferenceController, use one
mBackend.getConversations(false) in ConversationListSettings to improve,
this does not change the behavior because the result is filtered in
matchesFilter() both before and after.
3. Currently, we sort conversations first then filter them, change to
filter first then sort to reduce latency.

Fix: 215073227
Test: visual check & robo tests
Change-Id: I028a7fabbbf64cf5627e6615372282a36eb784e5

res/layout/conversation_onboarding.xml

@@ -15,12 +15,10 @@
 -->
 
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-              android:id="@+id/onboarding"
               android:layout_width="match_parent"
               android:layout_height="match_parent"
               android:layout_gravity="center"
               android:gravity="center"
-              android:visibility="gone"
               android:orientation="vertical">
 
     <ImageView

src/com/android/settings/notification/app/AllConversationsPreferenceController.java

@@ -17,26 +17,18 @@
 package com.android.settings.notification.app;
 
 import android.content.Context;
-import android.os.AsyncTask;
 import android.service.notification.ConversationChannelWrapper;
 
 import androidx.preference.Preference;
-import androidx.preference.PreferenceCategory;
 
 import com.android.settings.R;
 import com.android.settings.notification.NotificationBackend;
 
-import java.util.Collections;
-import java.util.List;
-
 public class AllConversationsPreferenceController extends ConversationListPreferenceController {
 
     private static final String KEY = "other_conversations";
 
-    private List<ConversationChannelWrapper> mConversations;
+    public AllConversationsPreferenceController(Context context, NotificationBackend backend) {
-
-    public AllConversationsPreferenceController(Context context,
-            NotificationBackend backend) {
         super(context, backend);
     }
 
@@ -45,11 +37,6 @@ public class AllConversationsPreferenceController extends ConversationListPrefer
         return KEY;
     }
 
-    @Override
-    public boolean isAvailable() {
-        return true;
-    }
-
     @Override
     Preference getSummaryPreference() {
         Preference pref = new Preference(mContext);
@@ -63,15 +50,4 @@ public class AllConversationsPreferenceController extends ConversationListPrefer
     boolean matchesFilter(ConversationChannelWrapper conversation) {
         return !conversation.getNotificationChannel().isImportantConversation();
     }
-
-    @Override
-    public void updateState(Preference preference) {
-        PreferenceCategory pref = (PreferenceCategory) preference;
-        // Load conversations
-
-        mConversations = mBackend.getConversations(false).getList();
-        Collections.sort(mConversations, mConversationComparator);
-
-        populateList(mConversations, pref);
-    }
 }

src/com/android/settings/notification/app/ConversationListPreferenceController.java

@@ -25,8 +25,10 @@ import android.provider.Settings;
 import android.service.notification.ConversationChannelWrapper;
 import android.text.TextUtils;
 
+import androidx.annotation.VisibleForTesting;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceGroup;
+import androidx.preference.PreferenceScreen;
 
 import com.android.settings.R;
 import com.android.settings.applications.AppInfoBase;
@@ -38,14 +40,15 @@ import com.android.settingslib.widget.AppPreference;
 import java.text.Collator;
 import java.util.Comparator;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
 
 public abstract class ConversationListPreferenceController extends AbstractPreferenceController {
 
     private static final String SUMMARY_KEY_SUFFIX = "_summary";
     protected final NotificationBackend mBackend;
+    private PreferenceGroup mPreferenceGroup;
 
-    public ConversationListPreferenceController(Context context,
+    public ConversationListPreferenceController(Context context, NotificationBackend backend) {
-            NotificationBackend backend) {
         super(context);
         mBackend = backend;
     }
@@ -55,44 +58,55 @@ public abstract class ConversationListPreferenceController extends AbstractPrefe
         return true;
     }
 
-    protected void populateList(List<ConversationChannelWrapper> conversations,
+    @Override
-            PreferenceGroup containerGroup) {
+    public void displayPreference(PreferenceScreen screen) {
-        containerGroup.setVisible(false);
+        super.displayPreference(screen);
-        containerGroup.removeAll();
+        mPreferenceGroup = screen.findPreference(getPreferenceKey());
+    }
+
+    /**
+     * Updates the conversation list.
+     * @return true if this controller has content to display.
+     */
+    boolean updateList(List<ConversationChannelWrapper> conversations) {
+        mPreferenceGroup.setVisible(false);
+        mPreferenceGroup.removeAll();
         if (conversations != null) {
-            populateConversations(conversations, containerGroup);
+            populateConversations(conversations);
         }
 
-        if (containerGroup.getPreferenceCount() != 0) {
+        boolean hasContent = mPreferenceGroup.getPreferenceCount() != 0;
+        if (hasContent) {
             Preference summaryPref = getSummaryPreference();
             if (summaryPref != null) {
                 summaryPref.setKey(getPreferenceKey() + SUMMARY_KEY_SUFFIX);
-                containerGroup.addPreference(summaryPref);
+                mPreferenceGroup.addPreference(summaryPref);
             }
-            containerGroup.setVisible(true);
+            mPreferenceGroup.setVisible(true);
         }
+        return hasContent;
     }
 
     abstract Preference getSummaryPreference();
 
     abstract boolean matchesFilter(ConversationChannelWrapper conversation);
 
-    protected void populateConversations(List<ConversationChannelWrapper> conversations,
+    @VisibleForTesting
-            PreferenceGroup containerGroup) {
+    void populateConversations(List<ConversationChannelWrapper> conversations) {
-        int order = 100;
+        AtomicInteger order = new AtomicInteger(100);
-        for (ConversationChannelWrapper conversation : conversations) {
+        conversations.stream()
-            if (conversation.getNotificationChannel().isDemoted()
+                .filter(conversation -> !conversation.getNotificationChannel().isDemoted()
-                    || !matchesFilter(conversation)) {
+                        && matchesFilter(conversation))
-                continue;
+                .sorted(mConversationComparator)
-            }
+                .map(this::createConversationPref)
-            containerGroup.addPreference(createConversationPref(conversation, order++));
+                .forEachOrdered(preference -> {
-        }
+                    preference.setOrder(order.getAndIncrement());
+                    mPreferenceGroup.addPreference(preference);
+                });
     }
 
-    protected Preference createConversationPref(final ConversationChannelWrapper conversation,
+    private Preference createConversationPref(final ConversationChannelWrapper conversation) {
-            int order) {
         AppPreference pref = new AppPreference(mContext);
-        pref.setOrder(order);
 
         pref.setTitle(getTitle(conversation));
         pref.setSummary(getSummary(conversation));
@@ -141,7 +155,8 @@ public abstract class ConversationListPreferenceController extends AbstractPrefe
                 .setSourceMetricsCategory(SettingsEnums.NOTIFICATION_CONVERSATION_LIST_SETTINGS);
     }
 
-    protected Comparator<ConversationChannelWrapper> mConversationComparator =
+    @VisibleForTesting
+    Comparator<ConversationChannelWrapper> mConversationComparator =
             new Comparator<ConversationChannelWrapper>() {
                 private final Collator sCollator = Collator.getInstance();
                 @Override

src/com/android/settings/notification/app/ConversationListSettings.java

@@ -19,8 +19,9 @@ package com.android.settings.notification.app;
 import android.app.people.IPeopleManager;
 import android.app.settings.SettingsEnums;
 import android.content.Context;
+import android.os.Bundle;
 import android.os.ServiceManager;
-import android.util.Log;
+import android.service.notification.ConversationChannelWrapper;
 
 import com.android.settings.R;
 import com.android.settings.dashboard.DashboardFragment;
@@ -32,12 +33,16 @@ import java.util.List;
 
 public class ConversationListSettings extends DashboardFragment {
     private static final String TAG = "ConvoListSettings";
-    private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
 
     NotificationBackend mBackend = new NotificationBackend();
     IPeopleManager mPs;
 
     protected List<AbstractPreferenceController> mControllers = new ArrayList<>();
+    private NoConversationsPreferenceController mNoConversationsController;
+    private PriorityConversationsPreferenceController mPriorityConversationsController;
+    private AllConversationsPreferenceController mAllConversationsController;
+    private RecentConversationsPreferenceController mRecentConversationsController;
+    private boolean mUpdatedInOnCreate = false;
 
     public ConversationListSettings() {
         mPs = IPeopleManager.Stub.asInterface(
@@ -62,10 +67,43 @@ public class ConversationListSettings extends DashboardFragment {
     @Override
     protected List<AbstractPreferenceController> createPreferenceControllers(Context context) {
         mControllers = new ArrayList<>();
-        mControllers.add(new NoConversationsPreferenceController(context, mBackend, mPs));
+        mNoConversationsController = new NoConversationsPreferenceController(context);
-        mControllers.add(new PriorityConversationsPreferenceController(context, mBackend));
+        mControllers.add(mNoConversationsController);
-        mControllers.add(new AllConversationsPreferenceController(context, mBackend));
+        mPriorityConversationsController =
-        mControllers.add(new RecentConversationsPreferenceController(context, mBackend, mPs));
+                new PriorityConversationsPreferenceController(context, mBackend);
+        mControllers.add(mPriorityConversationsController);
+        mAllConversationsController = new AllConversationsPreferenceController(context, mBackend);
+        mControllers.add(mAllConversationsController);
+        mRecentConversationsController =
+                new RecentConversationsPreferenceController(context, mBackend, mPs);
+        mControllers.add(mRecentConversationsController);
         return new ArrayList<>(mControllers);
     }
+
+    @Override
+    public void onCreate(Bundle icicle) {
+        super.onCreate(icicle);
+        update();
+        mUpdatedInOnCreate = true;
+    }
+
+    @Override
+    public void onStart() {
+        super.onStart();
+        if (mUpdatedInOnCreate) {
+            mUpdatedInOnCreate = false;
+        } else {
+            update();
+        }
+    }
+
+    private void update() {
+        List<ConversationChannelWrapper> conversationList =
+                mBackend.getConversations(false).getList();
+        boolean hasContent = mPriorityConversationsController.updateList(conversationList)
+                | mAllConversationsController.updateList(conversationList)
+                | mRecentConversationsController.updateList();
+        mNoConversationsController.setAvailable(!hasContent);
+        mNoConversationsController.displayPreference(getPreferenceScreen());
+    }
 }

src/com/android/settings/notification/app/NoConversationsPreferenceController.java

@@ -16,32 +16,18 @@
 
 package com.android.settings.notification.app;
 
-import android.app.people.IPeopleManager;
 import android.content.Context;
-import android.os.AsyncTask;
-import android.os.RemoteException;
-import android.service.notification.ConversationChannelWrapper;
-import android.util.Log;
-import android.view.View;
 
-import androidx.preference.Preference;
+import com.android.settingslib.core.AbstractPreferenceController;
 
-import com.android.settings.R;
+class NoConversationsPreferenceController extends AbstractPreferenceController {
-import com.android.settings.notification.NotificationBackend;
-import com.android.settingslib.widget.LayoutPreference;
 
-public class NoConversationsPreferenceController extends ConversationListPreferenceController {
-
-    private static String TAG = "NoConversationsPC";
     private static final String KEY = "no_conversations";
 
-    private IPeopleManager mPs;
+    private boolean mIsAvailable = false;
-    private int mConversationCount = 0;
 
-    public NoConversationsPreferenceController(Context context,
+    NoConversationsPreferenceController(Context context) {
-            NotificationBackend backend, IPeopleManager ps) {
+        super(context);
-        super(context, backend);
-        mPs = ps;
     }
 
     @Override
@@ -51,44 +37,10 @@ public class NoConversationsPreferenceController extends ConversationListPrefere
 
     @Override
     public boolean isAvailable() {
-        return true;
+        return mIsAvailable;
     }
 
-    @Override
+    void setAvailable(boolean available) {
-    Preference getSummaryPreference() {
+        mIsAvailable = available;
-        return null;
-    }
-
-    @Override
-    boolean matchesFilter(ConversationChannelWrapper conversation) {
-        return false;
-    }
-
-    @Override
-    public void updateState(Preference preference) {
-        LayoutPreference pref = (LayoutPreference) preference;
-        // Load conversations
-        new AsyncTask<Void, Void, Void>() {
-            @Override
-            protected Void doInBackground(Void... unused) {
-                mConversationCount = mBackend.getConversations(false).getList().size();
-                try {
-                    mConversationCount += mPs.getRecentConversations().getList().size();
-                } catch (RemoteException e) {
-                    Log.w(TAG, "Error calling PS", e);
-                }
-                return null;
-            }
-
-            @Override
-            protected void onPostExecute(Void unused) {
-                if (mContext == null) {
-                    return;
-                }
-                pref.findViewById(R.id.onboarding).setVisibility(mConversationCount == 0
-                        ? View.VISIBLE : View.GONE);
-                preference.setVisible(mConversationCount == 0);
-            }
-        }.execute();
     }
 }

src/com/android/settings/notification/app/PriorityConversationsPreferenceController.java

@@ -17,26 +17,19 @@
 package com.android.settings.notification.app;
 
 import android.content.Context;
-import android.os.AsyncTask;
 import android.service.notification.ConversationChannelWrapper;
 
 import androidx.preference.Preference;
-import androidx.preference.PreferenceCategory;
 
 import com.android.settings.R;
 import com.android.settings.notification.NotificationBackend;
 
-import java.util.Collections;
-import java.util.List;
-
 public class PriorityConversationsPreferenceController extends
         ConversationListPreferenceController {
 
     private static final String KEY = "important_conversations";
-    private List<ConversationChannelWrapper> mConversations;
 
-    public PriorityConversationsPreferenceController(Context context,
+    public PriorityConversationsPreferenceController(Context context, NotificationBackend backend) {
-            NotificationBackend backend) {
         super(context, backend);
     }
 
@@ -45,11 +38,6 @@ public class PriorityConversationsPreferenceController extends
         return KEY;
     }
 
-    @Override
-    public boolean isAvailable() {
-        return true;
-    }
-
     @Override
     Preference getSummaryPreference() {
         Preference pref = new Preference(mContext);
@@ -63,14 +51,4 @@ public class PriorityConversationsPreferenceController extends
     boolean matchesFilter(ConversationChannelWrapper conversation) {
         return conversation.getNotificationChannel().isImportantConversation();
     }
-
-    @Override
-    public void updateState(Preference preference) {
-        PreferenceCategory pref = (PreferenceCategory) preference;
-        // Load conversations
-        mConversations = mBackend.getConversations(true).getList();
-        Collections.sort(mConversations, mConversationComparator);
-
-        populateList(mConversations, pref);
-    }
 }

src/com/android/settings/notification/app/RecentConversationsPreferenceController.java

@@ -30,9 +30,10 @@ import android.provider.Settings;
 import android.util.Slog;
 import android.widget.Button;
 
+import androidx.annotation.VisibleForTesting;
 import androidx.preference.Preference;
-import androidx.preference.PreferenceCategory;
 import androidx.preference.PreferenceGroup;
+import androidx.preference.PreferenceScreen;
 
 import com.android.settings.R;
 import com.android.settings.applications.AppInfoBase;
@@ -45,18 +46,20 @@ import java.text.Collator;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
 
 public class RecentConversationsPreferenceController extends AbstractPreferenceController {
 
     private static final String TAG = "RecentConversationsPC";
     private static final String KEY = "recent_conversations";
     private static final String CLEAR_ALL_KEY_SUFFIX = "_clear_all";
-    private List<ConversationChannel> mConversations;
     private final IPeopleManager mPs;
     private final NotificationBackend mBackend;
+    private PreferenceGroup mPreferenceGroup;
 
-    public RecentConversationsPreferenceController(Context context, NotificationBackend backend,
+    public RecentConversationsPreferenceController(
-            IPeopleManager ps) {
+            Context context, NotificationBackend backend, IPeopleManager ps) {
         super(context);
         mBackend = backend;
         mPs = ps;
@@ -103,63 +106,69 @@ public class RecentConversationsPreferenceController extends AbstractPreferenceC
     }
 
     @Override
-    public void updateState(Preference preference) {
+    public void displayPreference(PreferenceScreen screen) {
-        PreferenceCategory pref = (PreferenceCategory) preference;
+        super.displayPreference(screen);
-        // Load conversations
+        mPreferenceGroup = screen.findPreference(getPreferenceKey());
-        try {
-            mConversations = mPs.getRecentConversations().getList();
-        } catch (RemoteException e) {
-            Slog.w(TAG, "Could get recents", e);
-        }
-        Collections.sort(mConversations, mConversationComparator);
-
-        populateList(mConversations, pref);
-
     }
 
-    protected void populateList(List<ConversationChannel> conversations,
+    /**
-            PreferenceGroup containerGroup) {
+     * Updates the conversation list.
-        containerGroup.removeAll();
+     *
+     * @return true if this controller has content to display.
+     */
+    boolean updateList() {
+        // Load conversations
+        List<ConversationChannel> conversations = Collections.emptyList();
+        try {
+            conversations = mPs.getRecentConversations().getList();
+        } catch (RemoteException e) {
+            Slog.w(TAG, "Could not get recent conversations", e);
+        }
+
+        return populateList(conversations);
+    }
+
+    @VisibleForTesting
+    boolean populateList(List<ConversationChannel> conversations) {
+        mPreferenceGroup.removeAll();
         boolean hasClearable = false;
         if (conversations != null) {
-            hasClearable = populateConversations(conversations, containerGroup);
+            hasClearable = populateConversations(conversations);
         }
 
-        if (containerGroup.getPreferenceCount() == 0) {
+        boolean hashContent = mPreferenceGroup.getPreferenceCount() != 0;
-            containerGroup.setVisible(false);
+        mPreferenceGroup.setVisible(hashContent);
-        } else {
+        if (hashContent && hasClearable) {
-            containerGroup.setVisible(true);
+            Preference clearAll = getClearAll(mPreferenceGroup);
-            if (hasClearable) {
+            if (clearAll != null) {
-                Preference clearAll = getClearAll(containerGroup);
+                mPreferenceGroup.addPreference(clearAll);
-                if (clearAll != null) {
-                    containerGroup.addPreference(clearAll);
-                }
             }
         }
+        return hashContent;
     }
 
-    protected boolean populateConversations(List<ConversationChannel> conversations,
+    protected boolean populateConversations(List<ConversationChannel> conversations) {
-            PreferenceGroup containerGroup) {
+        AtomicInteger order = new AtomicInteger(100);
-        int order = 100;
+        AtomicBoolean hasClearable = new AtomicBoolean(false);
-        boolean hasClearable = false;
+        conversations.stream()
-        for (ConversationChannel conversation : conversations) {
+                .filter(conversation ->
-            if (conversation.getNotificationChannel().getImportance() == IMPORTANCE_NONE
+                        conversation.getNotificationChannel().getImportance() != IMPORTANCE_NONE
-                    || (conversation.getNotificationChannelGroup() != null
+                                && (conversation.getNotificationChannelGroup() == null
-                    && conversation.getNotificationChannelGroup().isBlocked())) {
+                                || !conversation.getNotificationChannelGroup().isBlocked()))
-                continue;
+                .sorted(mConversationComparator)
-            }
+                .map(this::createConversationPref)
-            RecentConversationPreference pref =
+                .forEachOrdered(pref -> {
-                    createConversationPref(containerGroup, conversation, order++);
+                    pref.setOrder(order.getAndIncrement());
-            containerGroup.addPreference(pref);
+                    mPreferenceGroup.addPreference(pref);
-            if (pref.hasClearListener()) {
+                    if (pref.hasClearListener()) {
-                hasClearable = true;
+                        hasClearable.set(true);
-            }
+                    }
-        }
+                });
-        return hasClearable;
+        return hasClearable.get();
     }
 
-    protected RecentConversationPreference createConversationPref(PreferenceGroup parent,
+    protected RecentConversationPreference createConversationPref(
-            final ConversationChannel conversation, int order) {
+            final ConversationChannel conversation) {
         final String pkg = conversation.getShortcutInfo().getPackage();
         final int uid = conversation.getUid();
         final String conversationId = conversation.getShortcutInfo().getId();
@@ -171,13 +180,12 @@ public class RecentConversationsPreferenceController extends AbstractPreferenceC
                     mPs.removeRecentConversation(pkg, UserHandle.getUserId(uid), conversationId);
                     pref.getClearView().announceForAccessibility(
                             mContext.getString(R.string.recent_convo_removed));
-                    parent.removePreference(pref);
+                    mPreferenceGroup.removePreference(pref);
                 } catch (RemoteException e) {
                     Slog.w(TAG, "Could not clear recent", e);
                 }
             });
         }
-        pref.setOrder(order);
 
         pref.setTitle(getTitle(conversation));
         pref.setSummary(getSummary(conversation));
@@ -230,9 +238,11 @@ public class RecentConversationsPreferenceController extends AbstractPreferenceC
                 .setSourceMetricsCategory(SettingsEnums.NOTIFICATION_CONVERSATION_LIST_SETTINGS);
     }
 
-    protected Comparator<ConversationChannel> mConversationComparator =
+    @VisibleForTesting
+    Comparator<ConversationChannel> mConversationComparator =
             new Comparator<ConversationChannel>() {
                 private final Collator sCollator = Collator.getInstance();
+
                 @Override
                 public int compare(ConversationChannel o1, ConversationChannel o2) {
                     int labelComparison = 0;

tests/robotests/src/com/android/settings/notification/app/ConversationListPreferenceControllerTest.java

@@ -21,7 +21,6 @@ import static com.google.common.truth.Truth.assertThat;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
-import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -35,47 +34,49 @@ import android.provider.Settings;
 import android.service.notification.ConversationChannelWrapper;
 import android.text.SpannableStringBuilder;
 import android.text.Spanned;
-import android.text.style.BulletSpan;
-import android.text.style.QuoteSpan;
 import android.text.style.SubscriptSpan;
-import android.text.style.UnderlineSpan;
 
 import androidx.preference.Preference;
 import androidx.preference.PreferenceCategory;
+import androidx.preference.PreferenceGroup;
 import androidx.preference.PreferenceManager;
 import androidx.preference.PreferenceScreen;
+import androidx.test.core.app.ApplicationProvider;
 
 import com.android.settings.applications.AppInfoBase;
 import com.android.settings.notification.NotificationBackend;
 
+import com.google.common.collect.ImmutableList;
+
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.mockito.Answers;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
+import org.mockito.Spy;
 import org.robolectric.RobolectricTestRunner;
-import org.robolectric.RuntimeEnvironment;
-import org.robolectric.shadows.ShadowApplication;
-
-import java.util.ArrayList;
 
 @RunWith(RobolectricTestRunner.class)
 public class ConversationListPreferenceControllerTest {
 
-    @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+    private final Context mContext = ApplicationProvider.getApplicationContext();
-    private Context mContext;
     @Mock
     private NotificationBackend mBackend;
+    @Spy
+    private PreferenceGroup mPreferenceGroup = new PreferenceCategory(mContext);
 
     private TestPreferenceController mController;
 
     @Before
     public void setUp() {
         MockitoAnnotations.initMocks(this);
-        ShadowApplication shadowApplication = ShadowApplication.getInstance();
-        mContext = RuntimeEnvironment.application;
         mController = new TestPreferenceController(mContext, mBackend);
+
+        PreferenceManager preferenceManager = new PreferenceManager(mContext);
+        PreferenceScreen preferenceScreen = preferenceManager.createPreferenceScreen(mContext);
+        mPreferenceGroup.setKey(mController.getPreferenceKey());
+        preferenceScreen.addPreference(mPreferenceGroup);
+        mController.displayPreference(preferenceScreen);
     }
 
     @Test
@@ -84,39 +85,30 @@ public class ConversationListPreferenceControllerTest {
     }
 
     @Test
-    public void testPopulateList_hideIfNoConversations() {
+    public void testUpdateList_hideIfNoConversations() {
-        PreferenceCategory outerContainer = mock(PreferenceCategory.class);
+        boolean hasContent = mController.updateList(ImmutableList.of());
 
-        mController.populateList(new ArrayList<>(), outerContainer);
+        assertThat(hasContent).isFalse();
-
+        verify(mPreferenceGroup).setVisible(false);
-        verify(outerContainer).setVisible(false);
+        verify(mPreferenceGroup, never()).addPreference(any());
-        verify(outerContainer, never()).addPreference(any());
     }
 
     @Test
-    public void testPopulateList_validConversations() {
+    public void testUpdateList_validConversations() {
-        final PreferenceManager preferenceManager = new PreferenceManager(mContext);
-        PreferenceScreen ps = preferenceManager.createPreferenceScreen(mContext);
-        PreferenceCategory outerContainer = spy(new PreferenceCategory(mContext));
-        ps.addPreference(outerContainer);
-
         ConversationChannelWrapper ccw = new ConversationChannelWrapper();
         ccw.setNotificationChannel(mock(NotificationChannel.class));
         ccw.setPkg("pkg");
         ccw.setUid(1);
         ccw.setShortcutInfo(mock(ShortcutInfo.class));
 
-        ArrayList<ConversationChannelWrapper> list = new ArrayList<>();
+        boolean hasContent = mController.updateList(ImmutableList.of(ccw));
-        list.add(ccw);
 
-        mController.populateList(list, outerContainer);
+        assertThat(hasContent).isTrue();
-        verify(outerContainer, times(1)).addPreference(any());
+        verify(mPreferenceGroup, times(1)).addPreference(any());
     }
 
     @Test
     public void populateConversations() {
-        PreferenceCategory container = mock(PreferenceCategory.class);
-
         ConversationChannelWrapper ccw = new ConversationChannelWrapper();
         ccw.setNotificationChannel(mock(NotificationChannel.class));
         ccw.setPkg("pkg");
@@ -131,13 +123,9 @@ public class ConversationListPreferenceControllerTest {
         ccwDemoted.setUid(1);
         ccwDemoted.setShortcutInfo(mock(ShortcutInfo.class));
 
-        ArrayList<ConversationChannelWrapper> list = new ArrayList<>();
+        mController.populateConversations(ImmutableList.of(ccw, ccwDemoted));
-        list.add(ccw);
-        list.add(ccwDemoted);
 
-        mController.populateConversations(list, container);
+        verify(mPreferenceGroup, times(1)).addPreference(any());
-
-        verify(container, times(1)).addPreference(any());
     }
 
     @Test
@@ -240,7 +228,8 @@ public class ConversationListPreferenceControllerTest {
         assertThat(mController.mConversationComparator.compare(one, two)).isLessThan(0);
     }
 
-    private final class TestPreferenceController extends ConversationListPreferenceController {
+    private static final class TestPreferenceController extends
+            ConversationListPreferenceController {
 
         private TestPreferenceController(Context context, NotificationBackend backend) {
             super(context, backend);

tests/robotests/src/com/android/settings/notification/app/RecentConversationsPreferenceControllerTest.java

@@ -37,9 +37,7 @@ import android.os.Bundle;
 import android.os.UserHandle;
 import android.provider.Settings;
 import android.text.SpannedString;
-import android.view.LayoutInflater;
 import android.view.View;
-import android.widget.LinearLayout;
 
 import androidx.preference.Preference;
 import androidx.preference.PreferenceCategory;
@@ -47,42 +45,46 @@ import androidx.preference.PreferenceGroup;
 import androidx.preference.PreferenceManager;
 import androidx.preference.PreferenceScreen;
 import androidx.preference.PreferenceViewHolder;
+import androidx.test.core.app.ApplicationProvider;
 
 import com.android.settings.R;
 import com.android.settings.applications.AppInfoBase;
 import com.android.settings.notification.NotificationBackend;
 import com.android.settingslib.widget.LayoutPreference;
 
+import com.google.common.collect.ImmutableList;
+
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.mockito.Answers;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
+import org.mockito.Spy;
 import org.robolectric.RobolectricTestRunner;
-import org.robolectric.RuntimeEnvironment;
-import org.robolectric.shadows.ShadowApplication;
-
-import java.util.ArrayList;
 
 @RunWith(RobolectricTestRunner.class)
 public class RecentConversationsPreferenceControllerTest {
 
-    @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+    private final Context mContext = ApplicationProvider.getApplicationContext();
-    private Context mContext;
     @Mock
     private NotificationBackend mBackend;
     @Mock
     private IPeopleManager mPs;
+    @Spy
+    private PreferenceGroup mPreferenceGroup = new PreferenceCategory(mContext);
 
     private RecentConversationsPreferenceController mController;
 
     @Before
     public void setUp() {
         MockitoAnnotations.initMocks(this);
-        ShadowApplication shadowApplication = ShadowApplication.getInstance();
-        mContext = RuntimeEnvironment.application;
         mController = new RecentConversationsPreferenceController(mContext, mBackend, mPs);
+
+        PreferenceManager preferenceManager = new PreferenceManager(mContext);
+        PreferenceScreen preferenceScreen = preferenceManager.createPreferenceScreen(mContext);
+        mPreferenceGroup.setKey(mController.getPreferenceKey());
+        preferenceScreen.addPreference(mPreferenceGroup);
+        mController.displayPreference(preferenceScreen);
     }
 
     @Test
@@ -92,38 +94,29 @@ public class RecentConversationsPreferenceControllerTest {
 
     @Test
     public void testPopulateList_hideIfNoConversations() {
-        PreferenceCategory outerContainer = mock(PreferenceCategory.class);
+        boolean hasContent = mController.populateList(ImmutableList.of());
 
-        mController.populateList(new ArrayList<>(), outerContainer);
+        assertThat(hasContent).isFalse();
-
+        verify(mPreferenceGroup).setVisible(false);
-        verify(outerContainer).setVisible(false);
+        verify(mPreferenceGroup, never()).addPreference(any());
-        verify(outerContainer, never()).addPreference(any());
     }
 
     @Test
     public void testPopulateList_validConversations() {
-        final PreferenceManager preferenceManager = new PreferenceManager(mContext);
-        PreferenceScreen ps = preferenceManager.createPreferenceScreen(mContext);
-        PreferenceCategory outerContainer = spy(new PreferenceCategory(mContext));
-        ps.addPreference(outerContainer);
-
         ConversationChannel ccw = new ConversationChannel(mock(ShortcutInfo.class), 6,
                 new NotificationChannel("hi", "hi", 4),
                 new NotificationChannelGroup("hi", "hi"), 7,
                 false);
 
-        ArrayList<ConversationChannel> list = new ArrayList<>();
+        boolean hasContent = mController.populateList(ImmutableList.of(ccw));
-        list.add(ccw);
 
-        mController.populateList(list, outerContainer);
+        assertThat(hasContent).isTrue();
         // one for the preference, one for the button ro clear all
-        verify(outerContainer, times(2)).addPreference(any());
+        verify(mPreferenceGroup, times(2)).addPreference(any());
     }
 
     @Test
     public void populateConversations_blocked() {
-        PreferenceCategory container = mock(PreferenceCategory.class);
-
         ConversationChannel ccw = new ConversationChannel(mock(ShortcutInfo.class), 6,
                 new NotificationChannel("hi", "hi", 4),
                 new NotificationChannelGroup("hi", "hi"), 7,
@@ -141,14 +134,10 @@ public class RecentConversationsPreferenceControllerTest {
                 blockedGroup, 7,
                 false);
 
-        ArrayList<ConversationChannel> list = new ArrayList<>();
+        boolean hasContent = mController.populateConversations(ImmutableList.of(ccw, ccw2, ccw3));
-        list.add(ccw);
-        list.add(ccw2);
-        list.add(ccw3);
 
-        mController.populateConversations(list, container);
+        assertThat(hasContent).isTrue();
-
+        verify(mPreferenceGroup, times(1)).addPreference(any());
-        verify(container, times(1)).addPreference(any());
     }
 
     @Test
@@ -223,8 +212,7 @@ public class RecentConversationsPreferenceControllerTest {
                 new NotificationChannelGroup("hi", "group"), 7,
                 true);
 
-        Preference pref = mController.createConversationPref(new PreferenceCategory(mContext),
+        Preference pref = mController.createConversationPref(ccw);
-                ccw, 100);
         try {
             pref.performClick();
         } catch (RuntimeException e) {
@@ -244,9 +232,7 @@ public class RecentConversationsPreferenceControllerTest {
                 new NotificationChannelGroup("hi", "group"), 7,
                 false);
 
-        RecentConversationPreference pref =
+        RecentConversationPreference pref = mController.createConversationPref(ccw);
-                (RecentConversationPreference) mController.createConversationPref(
-                        new PreferenceCategory(mContext), ccw, 100);
         final View view = View.inflate(mContext, pref.getLayoutResource(), null);
         PreferenceViewHolder holder = spy(PreferenceViewHolder.createInstanceForTests(view));
         View delete = View.inflate(mContext, pref.getSecondTargetResId(), null);
@@ -274,34 +260,28 @@ public class RecentConversationsPreferenceControllerTest {
                 new NotificationChannelGroup("hi", "group"), 7,
                 true);
 
-        PreferenceCategory group = new PreferenceCategory(mContext);
+        RecentConversationPreference pref = mController.createConversationPref(ccw);
-        PreferenceScreen screen = new PreferenceManager(mContext).createPreferenceScreen(mContext);
-        screen.addPreference(group);
-
-        RecentConversationPreference pref = mController.createConversationPref(
-                        new PreferenceCategory(mContext), ccw, 100);
         final View view = View.inflate(mContext, pref.getLayoutResource(), null);
         PreferenceViewHolder holder = spy(PreferenceViewHolder.createInstanceForTests(view));
         View delete = View.inflate(mContext, pref.getSecondTargetResId(), null);
         when(holder.findViewById(pref.getClearId())).thenReturn(delete);
-        group.addPreference(pref);
+        mPreferenceGroup.addPreference(pref);
 
-        RecentConversationPreference pref2 = mController.createConversationPref(
+        RecentConversationPreference pref2 = mController.createConversationPref(ccw2);
-                        new PreferenceCategory(mContext), ccw2, 100);
         final View view2 = View.inflate(mContext, pref2.getLayoutResource(), null);
         PreferenceViewHolder holder2 = spy(PreferenceViewHolder.createInstanceForTests(view2));
         View delete2 = View.inflate(mContext, pref2.getSecondTargetResId(), null);
         when(holder2.findViewById(pref.getClearId())).thenReturn(delete2);
-        group.addPreference(pref2);
+        mPreferenceGroup.addPreference(pref2);
 
-        LayoutPreference clearAll = mController.getClearAll(group);
+        LayoutPreference clearAll = mController.getClearAll(mPreferenceGroup);
-        group.addPreference(clearAll);
+        mPreferenceGroup.addPreference(clearAll);
 
         clearAll.findViewById(R.id.conversation_settings_clear_recents).performClick();
 
         verify(mPs).removeAllRecentConversations();
-        assertThat((Preference) group.findPreference("hi:person")).isNull();
+        assertThat((Preference) mPreferenceGroup.findPreference("hi:person")).isNull();
-        assertThat((Preference) group.findPreference("bye:person")).isNotNull();
+        assertThat((Preference) mPreferenceGroup.findPreference("bye:person")).isNotNull();
     }
 
     @Test
@@ -314,30 +294,23 @@ public class RecentConversationsPreferenceControllerTest {
                 new NotificationChannelGroup("hi", "group"), 7,
                 true);
 
-        RecentConversationPreference pref =
+        RecentConversationPreference pref = mController.createConversationPref(ccw);
-                (RecentConversationPreference) mController.createConversationPref(
+
-                        new PreferenceCategory(mContext), ccw, 100);
         assertThat(pref.hasClearListener()).isFalse();
     }
 
     @Test
     public void testPopulateList_onlyNonremoveableConversations() {
-        final PreferenceManager preferenceManager = new PreferenceManager(mContext);
-        PreferenceScreen ps = preferenceManager.createPreferenceScreen(mContext);
-        PreferenceCategory outerContainer = spy(new PreferenceCategory(mContext));
-        ps.addPreference(outerContainer);
-
         ConversationChannel ccw = new ConversationChannel(mock(ShortcutInfo.class), 6,
                 new NotificationChannel("hi", "hi", 4),
                 new NotificationChannelGroup("hi", "hi"), 7,
                 true /* hasactivenotifs */);
 
-        ArrayList<ConversationChannel> list = new ArrayList<>();
+        boolean hasContent = mController.populateList(ImmutableList.of(ccw));
-        list.add(ccw);
 
-        mController.populateList(list, outerContainer);
+        assertThat(hasContent).isTrue();
         // one for the preference, none for 'clear all'
-        verify(outerContainer, times(1)).addPreference(any());
+        verify(mPreferenceGroup, times(1)).addPreference(any());
     }
 
     @Test