package com.google.samples.apps.topeka.helper;

import android.app.Activity;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Pair;
import android.view.View;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * Helper class for creating content transitions used with {@link android.app.ActivityOptions}.
 */
public class TransitionHelper {

    /**
     * Create the transition participants required during a activity transition while
     * avoiding glitches with the system UI.
     *
     * @param activity The activity used as start for the transition.
     * @return All transition participants.
     */
    public static Pair[] createSafeTransitionParticipants(@NonNull Activity activity,
            @Nullable Pair... otherParticipants) {
        // Avoid system UI glitches as described here:
        // https://plus.google.com/+AlexLockwood/posts/RPtwZ5nNebb
        View decor = activity.getWindow().getDecorView();
        View statusBar = decor.findViewById(android.R.id.statusBarBackground);
        View navBar = decor.findViewById(android.R.id.navigationBarBackground);

        // Create pair of transition participants.
        List<Pair> participants = new ArrayList<>(3);
        addNonNullViewToTransitionParticipants(statusBar, participants);
        addNonNullViewToTransitionParticipants(navBar, participants);
        // only add transition participants if there's at least one none-null element
        if (otherParticipants != null && !(otherParticipants.length == 1
                && otherParticipants[0] == null)) {
            participants.addAll(Arrays.asList(otherParticipants));
        }
        return participants.toArray(new Pair[participants.size()]);
    }

    private static void addNonNullViewToTransitionParticipants(View view, List<Pair> participants) {
        if (view == null) {
            return;
        }
        participants.add(new Pair<>(view, view.getTransitionName()));
    }

}

@@ -1,8 +1,621 @@
+/*%0A * Copyright 2015 Google Inc. All Rights Reserved.%0A *%0A * Licensed under the Apache License, Version 2.0 (the %22License%22);%0A * you may not use this file except in compliance with the License.%0A * You may obtain a copy of the License at%0A *%0A * http://www.apache.org/licenses/LICENSE-2.0%0A *%0A * Unless required by applicable law or agreed to in writing, software%0A * distributed under the License is distributed on an %22AS IS%22 BASIS,%0A * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.%0A * See the License for the specific language governing permissions and%0A * limitations under the License.%0A */%0A%0A
 package 

Add missing header