Video Tutorials : Added unit test and java test for language picker

Bug: 1117157
Change-Id: I31a744b44c4cdb418b2ba11956d2eb54479ba579
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2429516
Commit-Queue: Shakti Sahu <shaktisahu@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811155}

chrome/android/BUILD.gn

@@ -829,6 +829,8 @@ junit_binary("chrome_junit_tests") {
     "//chrome/browser/ui/messages/android:junit",
     "//chrome/browser/user_education:java",
     "//chrome/browser/util:java",
+    "//chrome/browser/video_tutorials:java",
+    "//chrome/browser/video_tutorials/internal:junit",
     "//chrome/browser/xsurface:java",
     "//chrome/test/android:chrome_java_test_support",
     "//components/background_task_scheduler:background_task_scheduler_java",
@@ -2409,6 +2411,7 @@ chrome_test_apk_tmpl("chrome_public_test_apk") {
     "//chrome/browser/ui/android/appmenu/internal:javatests",
     "//chrome/browser/ui/messages/android:javatests",
     "//chrome/browser/util:javatests",
+    "//chrome/browser/video_tutorials/internal:javatests",
   ]
 
   data_deps = [ "//testing/buildbot/filters:chrome_public_test_apk_filters" ]

chrome/browser/video_tutorials/BUILD.gn

@@ -109,6 +109,15 @@ if (is_android) {
     # android_library target does not actually depend on this internal file.
     sources = [ "internal/android/java/src/org/chromium/chrome/browser/video_tutorials/VideoTutorialServiceFactory.java" ]
   }
+
+  android_library("test_support_java") {
+    sources = [ "android/java/src/org/chromium/chrome/browser/video_tutorials/test/TestVideoTutorialService.java" ]
+
+    deps = [
+      ":java",
+      "//base:base_java",
+    ]
+  }
 }
 
 group("unit_tests") {

chrome/browser/video_tutorials/android/java/src/org/chromium/chrome/browser/video_tutorials/test/TestVideoTutorialService.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.video_tutorials.test;
+
+import org.chromium.base.Callback;
+import org.chromium.chrome.browser.video_tutorials.FeatureType;
+import org.chromium.chrome.browser.video_tutorials.Language;
+import org.chromium.chrome.browser.video_tutorials.Tutorial;
+import org.chromium.chrome.browser.video_tutorials.VideoTutorialService;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/** A video tutorial service implementation for tests. */
+public class TestVideoTutorialService implements VideoTutorialService {
+    public static final Language HINDI = new Language("hi", "Hindi", "Hindi Native");
+    public static final Language TAMIL = new Language("ta", "Tamil", "Tamil Native");
+    public static final Language ENGLISH = new Language("en", "English", "English Native");
+
+    private final List<Tutorial> mTutorials = new ArrayList<>();
+    private final List<Language> mLanguages = new ArrayList<>();
+    private String mPreferredLocale;
+
+    public TestVideoTutorialService() {
+        initializeLanguages();
+        mPreferredLocale = HINDI.locale;
+        initializeTutorialList();
+    }
+
+    @Override
+    public void getTutorials(Callback<List<Tutorial>> callback) {
+        callback.onResult(mTutorials);
+    }
+
+    @Override
+    public void getTutorial(int featureType, Callback<Tutorial> callback) {
+        for (Tutorial tutorial : mTutorials) {
+            if (tutorial.featureType == featureType) callback.onResult(tutorial);
+        }
+    }
+
+    @Override
+    public List<Language> getSupportedLanguages() {
+        return mLanguages;
+    }
+
+    @Override
+    public String getPreferredLocale() {
+        return mPreferredLocale;
+    }
+
+    @Override
+    public void setPreferredLocale(String locale) {
+        mPreferredLocale = locale;
+    }
+
+    public List<Language> getTestLanguages() {
+        return mLanguages;
+    }
+
+    public List<Tutorial> getTestTutorials() {
+        return mTutorials;
+    }
+
+    private void initializeTutorialList() {
+        mTutorials.add(new Tutorial(FeatureType.DOWNLOAD,
+                "How to use Google Chrome's download functionality",
+                "https://storage.googleapis.com/stock-wizard.appspot.com/portrait.jpg",
+                "https://storage.googleapis.com/stock-wizard.appspot.com/portrait.jpg",
+                "caption url", "share url", 35));
+
+        mTutorials.add(
+                new Tutorial(FeatureType.SEARCH, "How to efficiently search with Google Chrome",
+                        "https://storage.googleapis.com/stock-wizard.appspot.com/elephant.jpg ",
+                        "https://storage.googleapis.com/stock-wizard.appspot.com/elephant.jpg",
+                        "caption url", "share url", 35));
+    }
+
+    private void initializeLanguages() {
+        mLanguages.add(HINDI);
+        mLanguages.add(TAMIL);
+        mLanguages.add(ENGLISH);
+    }
+}

chrome/browser/video_tutorials/internal/BUILD.gn

@@ -68,6 +68,7 @@ if (is_android) {
       "android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguageItemProperties.java",
       "android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguageItemViewHolder.java",
       "android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerCoordinator.java",
+      "android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerMediator.java",
       "android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerProperties.java",
       "android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerView.java",
       "android/java/src/org/chromium/chrome/browser/video_tutorials/player/VideoPlayerCoordinatorImpl.java",
@@ -133,6 +134,48 @@ if (is_android) {
       "android/java/src/org/chromium/chrome/browser/video_tutorials/bridges/VideoTutorialServiceBridge.java",
     ]
   }
+
+  java_library("junit") {
+    # Skip platform checks since Robolectric depends on requires_android targets.
+    bypass_platform_checks = true
+    testonly = true
+    sources = [ "android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerMediatorUnitTest.java" ]
+    deps = [
+      ":java",
+      "//base:base_java",
+      "//base:base_junit_test_support",
+      "//chrome/browser/video_tutorials:java",
+      "//chrome/browser/video_tutorials:test_support_java",
+      "//third_party/android_deps:robolectric_all_java",
+      "//third_party/hamcrest:hamcrest_core_java",
+      "//third_party/junit",
+      "//third_party/mockito:mockito_java",
+      "//ui/android:ui_java",
+    ]
+  }
+
+  android_library("javatests") {
+    testonly = true
+
+    sources = [ "android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerTest.java" ]
+    deps = [
+      ":java",
+      "//base:base_java",
+      "//base:base_java_test_support",
+      "//chrome/browser/video_tutorials:java",
+      "//chrome/browser/video_tutorials:test_support_java",
+      "//chrome/test/android:chrome_java_test_support",
+      "//content/public/test/android:content_java_test_support",
+      "//third_party/android_deps:androidx_annotation_annotation_java",
+      "//third_party/android_deps:androidx_test_runner_java",
+      "//third_party/android_deps:espresso_java",
+      "//third_party/android_support_test_runner:rules_java",
+      "//third_party/hamcrest:hamcrest_core_java",
+      "//third_party/junit",
+      "//third_party/mockito:mockito_java",
+      "//ui/android:ui_java_test_support",
+    ]
+  }
 }
 
 source_set("unit_tests") {

chrome/browser/video_tutorials/internal/android/java/res/layout/language_picker.xml

@@ -23,6 +23,7 @@
         android:src="@drawable/btn_close" />
 
     <TextView
+        android:id="@+id/title_view"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_marginBottom="36dp"

chrome/browser/video_tutorials/internal/android/java/src/org/chromium/chrome/browser/video_tutorials/iph/VideoIPHView.java

@@ -13,6 +13,7 @@ import android.widget.TextView;
 
 import androidx.annotation.Nullable;
 
+import org.chromium.chrome.browser.video_tutorials.R;
 import org.chromium.ui.modelutil.PropertyKey;
 import org.chromium.ui.modelutil.PropertyModel;
 
@@ -35,24 +36,21 @@ class VideoIPHView {
     }
 
     private void setTitle(String title) {
-        TextView view =
-                mCardView.findViewById(org.chromium.chrome.browser.video_tutorials.R.id.title);
+        TextView view = mCardView.findViewById(R.id.title);
         view.setText(title);
     }
 
     /** Called to set the video length text of an IPH. */
     private void setVideoLength(String videoLength) {
-        TextView view = mCardView.findViewById(
-                org.chromium.chrome.browser.video_tutorials.R.id.video_length);
+        TextView view = mCardView.findViewById(R.id.video_length);
         view.setText(videoLength);
     }
 
     private void setThumbnail(@Nullable Bitmap bitmap) {
-        ImageView view =
-                mCardView.findViewById(org.chromium.chrome.browser.video_tutorials.R.id.thumbnail);
+        ImageView view = mCardView.findViewById(R.id.thumbnail);
         if (bitmap == null) {
-            view.setImageDrawable(new ColorDrawable(view.getResources().getColor(
-                    org.chromium.chrome.browser.video_tutorials.R.color.image_loading_color)));
+            view.setImageDrawable(
+                    new ColorDrawable(view.getResources().getColor(R.color.image_loading_color)));
         } else {
             view.setImageBitmap(bitmap);
         }
@@ -63,8 +61,7 @@ class VideoIPHView {
     }
 
     private void setDismissListener(Runnable dismissListener) {
-        View closeButton = mCardView.findViewById(
-                org.chromium.chrome.browser.video_tutorials.R.id.close_button);
+        View closeButton = mCardView.findViewById(R.id.close_button);
         closeButton.setOnClickListener(view -> {
             mCardView.setVisibility(View.GONE);
             dismissListener.run();

chrome/browser/video_tutorials/internal/android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguageItemViewHolder.java

@@ -21,8 +21,7 @@ class LanguageItemViewHolder {
     /** Builder method to create the language item view. */
     public static View buildView(ViewGroup parent) {
         return LayoutInflater.from(parent.getContext())
-                .inflate(org.chromium.chrome.browser.video_tutorials.R.layout.language_card, parent,
-                        false);
+                .inflate(R.layout.language_card, parent, false);
     }
 
     /** Binder method to bind the list view with the model properties. */

chrome/browser/video_tutorials/internal/android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerCoordinator.java

@@ -5,25 +5,19 @@
 package org.chromium.chrome.browser.video_tutorials.languages;
 
 import android.content.Context;
-import android.content.res.Resources;
-import android.text.TextUtils;
 import android.view.View;
 
-import org.chromium.chrome.browser.video_tutorials.Language;
 import org.chromium.chrome.browser.video_tutorials.VideoTutorialService;
-import org.chromium.ui.modelutil.MVCListAdapter.ListItem;
 import org.chromium.ui.modelutil.MVCListAdapter.ModelList;
 import org.chromium.ui.modelutil.PropertyModel;
 
-import java.util.ArrayList;
-import java.util.List;
-
 /**
  *  The top level coordinator for the language picker UI.
  */
 public class LanguagePickerCoordinator {
     private final Context mContext;
     private final VideoTutorialService mVideoTutorialService;
+    private final LanguagePickerMediator mMediator;
     private final LanguagePickerView mView;
     private final PropertyModel mModel;
     private final ModelList mListModel;
@@ -39,6 +33,7 @@ public class LanguagePickerCoordinator {
         mModel = new PropertyModel(LanguagePickerProperties.ALL_KEYS);
         mListModel = new ModelList();
         mView = new LanguagePickerView(view, mModel, mListModel);
+        mMediator = new LanguagePickerMediator(mContext, mModel, mListModel, videoTutorialService);
     }
 
     /**
@@ -47,41 +42,11 @@ public class LanguagePickerCoordinator {
      * @param closeCallback The callback to be invoked when the close button is clicked.
      */
     public void showLanguagePicker(Runnable doneCallback, Runnable closeCallback) {
-        mModel.set(LanguagePickerProperties.CLOSE_CALLBACK, closeCallback);
-        mModel.set(LanguagePickerProperties.WATCH_CALLBACK, doneCallback);
-        populateList(mVideoTutorialService.getSupportedLanguages());
+        mMediator.showLanguagePicker(doneCallback, closeCallback);
     }
 
     /** @return A {@link View} representing this coordinator. */
     public View getView() {
         return mView.getView();
     }
-
-    private void onLanguageSelected(String locale) {
-        mVideoTutorialService.setPreferredLocale(locale);
-        populateList(mVideoTutorialService.getSupportedLanguages());
-    }
-
-    private void populateList(List<Language> supportedLanguages) {
-        List<ListItem> listItems = new ArrayList<>();
-        for (Language locale : supportedLanguages) {
-            ListItem listItem = new ListItem(
-                    LanguageItemProperties.ITEM_VIEW_TYPE, buildListItemModelFromLocale(locale));
-            listItems.add(listItem);
-        }
-        mListModel.set(listItems);
-    }
-
-    private PropertyModel buildListItemModelFromLocale(Language language) {
-        Resources resources = mContext.getResources();
-        String preferredLocale = mVideoTutorialService.getPreferredLocale();
-        return new PropertyModel.Builder(LanguageItemProperties.ALL_KEYS)
-                .with(LanguageItemProperties.LOCALE, language.locale)
-                .with(LanguageItemProperties.NAME, language.name)
-                .with(LanguageItemProperties.NATIVE_NAME, language.nativeName)
-                .with(LanguageItemProperties.IS_SELECTED,
-                        TextUtils.equals(language.locale, preferredLocale))
-                .with(LanguageItemProperties.SELECTION_CALLBACK, this::onLanguageSelected)
-                .build();
-    }
 }

chrome/browser/video_tutorials/internal/android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerMediator.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.video_tutorials.languages;
+
+import android.content.Context;
+import android.text.TextUtils;
+
+import org.chromium.chrome.browser.video_tutorials.Language;
+import org.chromium.chrome.browser.video_tutorials.VideoTutorialService;
+import org.chromium.ui.modelutil.MVCListAdapter.ListItem;
+import org.chromium.ui.modelutil.MVCListAdapter.ModelList;
+import org.chromium.ui.modelutil.PropertyModel;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ *  The mediator for language selection UI.
+ */
+public class LanguagePickerMediator {
+    private final Context mContext;
+    private final VideoTutorialService mVideoTutorialService;
+    private final PropertyModel mModel;
+    private final ModelList mListModel;
+
+    /**
+     * Constructor.
+     * @param videoTutorialService The video tutorial service backend.
+     */
+    public LanguagePickerMediator(Context context, PropertyModel model, ModelList listModel,
+            VideoTutorialService videoTutorialService) {
+        mContext = context;
+        mVideoTutorialService = videoTutorialService;
+        mModel = model;
+        mListModel = listModel;
+    }
+
+    /**
+     * See {@link LanguagePickerCoordinator#showLanguagePicker(Runnable, Runnable)}.
+     */
+    public void showLanguagePicker(Runnable doneCallback, Runnable closeCallback) {
+        mModel.set(LanguagePickerProperties.CLOSE_CALLBACK, closeCallback);
+        mModel.set(LanguagePickerProperties.WATCH_CALLBACK, doneCallback);
+        populateList(mVideoTutorialService.getSupportedLanguages());
+    }
+
+    private void onLanguageSelected(String locale) {
+        mVideoTutorialService.setPreferredLocale(locale);
+        populateList(mVideoTutorialService.getSupportedLanguages());
+    }
+
+    private void populateList(List<Language> supportedLanguages) {
+        List<ListItem> listItems = new ArrayList<>();
+        for (Language locale : supportedLanguages) {
+            ListItem listItem = new ListItem(
+                    LanguageItemProperties.ITEM_VIEW_TYPE, buildListItemModelFromLocale(locale));
+            listItems.add(listItem);
+        }
+        mListModel.set(listItems);
+    }
+
+    private PropertyModel buildListItemModelFromLocale(Language language) {
+        String preferredLocale = mVideoTutorialService.getPreferredLocale();
+        return new PropertyModel.Builder(LanguageItemProperties.ALL_KEYS)
+                .with(LanguageItemProperties.LOCALE, language.locale)
+                .with(LanguageItemProperties.NAME, language.name)
+                .with(LanguageItemProperties.NATIVE_NAME, language.nativeName)
+                .with(LanguageItemProperties.IS_SELECTED,
+                        TextUtils.equals(language.locale, preferredLocale))
+                .with(LanguageItemProperties.SELECTION_CALLBACK, this::onLanguageSelected)
+                .build();
+    }
+}

chrome/browser/video_tutorials/internal/android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerMediatorUnitTest.java

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.video_tutorials.languages;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.mockito.Mockito.verify;
+
+import android.content.Context;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import org.chromium.base.metrics.test.ShadowRecordHistogram;
+import org.chromium.base.test.BaseRobolectricTestRunner;
+import org.chromium.chrome.browser.video_tutorials.test.TestVideoTutorialService;
+import org.chromium.ui.modelutil.MVCListAdapter.ListItem;
+import org.chromium.ui.modelutil.MVCListAdapter.ModelList;
+import org.chromium.ui.modelutil.PropertyKey;
+import org.chromium.ui.modelutil.PropertyModel;
+import org.chromium.ui.modelutil.PropertyObservable;
+
+/**
+ * Tests for {@link LanguagePickerMediator}.
+ */
+@RunWith(BaseRobolectricTestRunner.class)
+public class LanguagePickerMediatorUnitTest {
+    @Mock
+    Context mContext;
+    private TestVideoTutorialService mTestVideoTutorialService;
+    private PropertyModel mModel;
+    private ModelList mListModel;
+    private LanguagePickerMediator mMediator;
+    @Mock
+    PropertyObservable.PropertyObserver<PropertyKey> mPropertyObserver;
+
+    @Before
+    public void setUp() {
+        ShadowRecordHistogram.reset();
+        MockitoAnnotations.initMocks(this);
+
+        mModel = new PropertyModel(LanguagePickerProperties.ALL_KEYS);
+        mModel.addObserver(mPropertyObserver);
+
+        mListModel = new ModelList();
+        mTestVideoTutorialService = new TestVideoTutorialService();
+        mMediator =
+                new LanguagePickerMediator(mContext, mModel, mListModel, mTestVideoTutorialService);
+    }
+
+    @Test
+    public void checkCallbacks() {
+        mMediator.showLanguagePicker(() -> {}, () -> {});
+        verify(mPropertyObserver)
+                .onPropertyChanged(mModel, LanguagePickerProperties.CLOSE_CALLBACK);
+        verify(mPropertyObserver)
+                .onPropertyChanged(mModel, LanguagePickerProperties.WATCH_CALLBACK);
+    }
+
+    @Test
+    public void loadsLanguagesInTheList() {
+        mMediator.showLanguagePicker(() -> {}, () -> {});
+
+        assertThat(mListModel.size(), equalTo(mTestVideoTutorialService.getTestLanguages().size()));
+        ListItem listItem = mListModel.get(0);
+        assertThat(listItem.model.get(LanguageItemProperties.NAME),
+                equalTo(TestVideoTutorialService.HINDI.name));
+        assertThat(listItem.model.get(LanguageItemProperties.NATIVE_NAME),
+                equalTo(TestVideoTutorialService.HINDI.nativeName));
+    }
+}

chrome/browser/video_tutorials/internal/android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerTest.java

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.video_tutorials.languages;
+
+import static androidx.test.espresso.Espresso.onView;
+import static androidx.test.espresso.assertion.ViewAssertions.matches;
+import static androidx.test.espresso.matcher.ViewMatchers.isDisplayed;
+import static androidx.test.espresso.matcher.ViewMatchers.withText;
+
+import android.app.Activity;
+import android.support.test.rule.ActivityTestRule;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.widget.FrameLayout;
+
+import androidx.test.espresso.action.ViewActions;
+import androidx.test.filters.SmallTest;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+
+import org.chromium.chrome.browser.video_tutorials.R;
+import org.chromium.chrome.browser.video_tutorials.VideoTutorialService;
+import org.chromium.chrome.browser.video_tutorials.test.TestVideoTutorialService;
+import org.chromium.chrome.test.ChromeJUnit4ClassRunner;
+import org.chromium.content_public.browser.test.util.TestThreadUtils;
+import org.chromium.ui.test.util.DummyUiActivity;
+
+/**
+ * Tests for {@link LanguagePickerCoordinator}.
+ */
+@RunWith(ChromeJUnit4ClassRunner.class)
+public class LanguagePickerTest {
+    @Rule
+    public ActivityTestRule<DummyUiActivity> mActivityTestRule =
+            new ActivityTestRule<>(DummyUiActivity.class);
+
+    private Activity mActivity;
+    private View mContentView;
+    private VideoTutorialService mVideoTutorialService;
+    private LanguagePickerCoordinator mCoordinator;
+
+    @Mock
+    private Runnable mWatchCallback;
+    @Mock
+    private Runnable mCloseCallback;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        mActivity = mActivityTestRule.getActivity();
+        TestThreadUtils.runOnUiThreadBlocking(() -> {
+            FrameLayout parentView = new FrameLayout(mActivity);
+            mActivity.setContentView(parentView);
+            mVideoTutorialService = new TestVideoTutorialService();
+            mContentView =
+                    LayoutInflater.from(mActivity).inflate(R.layout.language_picker, null, false);
+            parentView.addView(mContentView);
+            mCoordinator = new LanguagePickerCoordinator(mContentView, mVideoTutorialService);
+            mCoordinator.showLanguagePicker(mWatchCallback, mCloseCallback);
+        });
+    }
+
+    @Test
+    @SmallTest
+    public void testShowLanguages() {
+        onView(withText(TestVideoTutorialService.HINDI.name)).check(matches(isDisplayed()));
+        onView(withText(TestVideoTutorialService.HINDI.nativeName)).check(matches(isDisplayed()));
+        onView(withText("Watch")).check(matches(isDisplayed())).perform(ViewActions.click());
+        Mockito.verify(mWatchCallback).run();
+    }
+}

chrome/browser/video_tutorials/internal/android/java/src/org/chromium/chrome/browser/video_tutorials/languages/LanguagePickerView.java

@@ -45,7 +45,6 @@ class LanguagePickerView {
         LinearLayoutManager layoutManager =
                 new LinearLayoutManager(mView.getContext(), LinearLayoutManager.VERTICAL, false);
         recyclerView.setLayoutManager(layoutManager);
-
         SimpleRecyclerViewAdapter adapter = new SimpleRecyclerViewAdapter(mListModel);
         adapter.registerType(LanguageItemProperties.ITEM_VIEW_TYPE,
                 LanguageItemViewHolder::buildView, LanguageItemViewHolder::bindView);