Improve transition handling during sign in

Change-Id: I60c521c89ad51b0dc80ddde507c74c35e40736a0

app/src/main/java/com/google/samples/apps/topeka/activity/CategorySelectionActivity.java

@@ -43,7 +43,6 @@
 import com.google.samples.apps.topeka.helper.PreferencesHelper;
 import com.google.samples.apps.topeka.model.Player;
 import com.google.samples.apps.topeka.persistence.TopekaDatabaseHelper;
-import com.google.samples.apps.topeka.widget.AvatarView;
 
 public class CategorySelectionActivity extends AppCompatActivity {
 
@@ -138,7 +137,7 @@ private void signOut() {
                     .inflateTransition(R.transition.category_enter));
         }
         SignInActivity.start(this, false);
-        ActivityCompat.finishAfterTransition(this);
+        finish();
     }
 
     private void attachCategoryGridFragment() {

app/src/main/java/com/google/samples/apps/topeka/fragment/SignInFragment.java

@@ -17,6 +17,7 @@
 package com.google.samples.apps.topeka.fragment;
 
 import android.app.Activity;
+import android.os.Build;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.design.widget.FloatingActionButton;
@@ -27,6 +28,7 @@
 import android.support.v4.view.animation.FastOutSlowInInterpolator;
 import android.text.Editable;
 import android.text.TextWatcher;
+import android.transition.Transition;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -37,10 +39,12 @@
 import com.google.samples.apps.topeka.R;
 import com.google.samples.apps.topeka.activity.CategorySelectionActivity;
 import com.google.samples.apps.topeka.adapter.AvatarAdapter;
+import com.google.samples.apps.topeka.helper.ApiLevelHelper;
 import com.google.samples.apps.topeka.helper.PreferencesHelper;
 import com.google.samples.apps.topeka.helper.TransitionHelper;
 import com.google.samples.apps.topeka.model.Avatar;
 import com.google.samples.apps.topeka.model.Player;
+import com.google.samples.apps.topeka.widget.TransitionListenerAdapter;
 
 /**
  * Enable selection of an {@link Avatar} and user name.
@@ -217,18 +221,29 @@ public void onItemClick(AdapterView<?> parent, View view, int position, long id)
 
     private void performSignInWithTransition(View v) {
         final Activity activity = getActivity();
-        if (v == null) {
+        if (v == null || ApiLevelHelper.isLowerThan(Build.VERSION_CODES.LOLLIPOP)) {
             // Don't run a transition if the passed view is null
             CategorySelectionActivity.start(activity, mPlayer);
+            activity.finish();
             return;
         }
 
-        final Pair[] pairs = TransitionHelper.createSafeTransitionParticipants(activity, true,
-                new Pair<>(v, activity.getString(R.string.transition_avatar)));
-        @SuppressWarnings("unchecked")
-        ActivityOptionsCompat activityOptions = ActivityOptionsCompat
-                .makeSceneTransitionAnimation(activity, pairs);
-        CategorySelectionActivity.start(activity, mPlayer, activityOptions);
+        if (ApiLevelHelper.isAtLeast(Build.VERSION_CODES.LOLLIPOP)) {
+            activity.getWindow().getSharedElementExitTransition().addListener(
+                    new TransitionListenerAdapter() {
+                        @Override
+                        public void onTransitionEnd(Transition transition) {
+                            activity.finish();
+                        }
+                    });
+
+            final Pair[] pairs = TransitionHelper.createSafeTransitionParticipants(activity, true,
+                    new Pair<>(v, activity.getString(R.string.transition_avatar)));
+            @SuppressWarnings("unchecked")
+            ActivityOptionsCompat activityOptions = ActivityOptionsCompat
+                    .makeSceneTransitionAnimation(activity, pairs);
+            CategorySelectionActivity.start(activity, mPlayer, activityOptions);
+        }
     }
 
     private void initContents() {

app/src/main/java/com/google/samples/apps/topeka/widget/TransitionListenerAdapter.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.topeka.widget;
+
+import android.annotation.TargetApi;
+import android.os.Build;
+import android.transition.Transition;
+
+/**
+ * Empty implementation of {@link Transition.TransitionListener}.
+ */
+
+@TargetApi(Build.VERSION_CODES.KITKAT)
+public abstract class TransitionListenerAdapter implements Transition.TransitionListener {
+
+    @Override
+    public void onTransitionStart(Transition transition) { }
+
+    @Override
+    public void onTransitionEnd(Transition transition) { }
+
+    @Override
+    public void onTransitionCancel(Transition transition) { }
+
+    @Override
+    public void onTransitionPause(Transition transition) { }
+
+    @Override
+    public void onTransitionResume(Transition transition) { }
+}