media/MediaBrowserService/Application/src/main/java/com/example/android/mediasession/ui/MainActivity.java

/*
 * Copyright 2017 The Android Open Source Project
 *
 * 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.example.android.mediasession.ui;

import android.content.Context;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.media.MediaBrowserCompat;
import android.support.v4.media.MediaMetadataCompat;
import android.support.v4.media.session.MediaControllerCompat;
import android.support.v4.media.session.MediaSessionCompat;
import android.support.v4.media.session.PlaybackStateCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.android.mediasession.R;
import com.example.android.mediasession.client.MediaBrowserHelper;
import com.example.android.mediasession.service.MusicService;
import com.example.android.mediasession.service.contentcatalogs.MusicLibrary;

import java.util.List;

public class MainActivity extends AppCompatActivity {

    private ImageView mAlbumArt;
    private TextView mTitleTextView;
    private TextView mArtistTextView;
    private ImageView mMediaControlsImage;
    private MediaSeekBar mSeekBarAudio;

    private MediaBrowserHelper mMediaBrowserHelper;

    private boolean mIsPlaying;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mTitleTextView = findViewById(R.id.song_title);
        mArtistTextView = findViewById(R.id.song_artist);
        mAlbumArt = findViewById(R.id.album_art);
        mMediaControlsImage = findViewById(R.id.media_controls);
        mSeekBarAudio = findViewById(R.id.seekbar_audio);

        final ClickListener clickListener = new ClickListener();
        findViewById(R.id.button_previous).setOnClickListener(clickListener);
        findViewById(R.id.button_play).setOnClickListener(clickListener);
        findViewById(R.id.button_next).setOnClickListener(clickListener);

        mMediaBrowserHelper = new MediaBrowserConnection(this);
        mMediaBrowserHelper.registerCallback(new MediaBrowserListener());
    }

    @Override
    public void onStart() {
        super.onStart();
        mMediaBrowserHelper.onStart();
    }

    @Override
    public void onStop() {
        super.onStop();
        mSeekBarAudio.disconnectController();
        mMediaBrowserHelper.onStop();
    }

    /**
     * Convenience class to collect the click listeners together.
     * <p>
     * In a larger app it's better to split the listeners out or to use your favorite
     * library.
     */
    private class ClickListener implements View.OnClickListener {
        @Override
        public void onClick(View v) {
            switch (v.getId()) {
                case R.id.button_previous:
                    mMediaBrowserHelper.getTransportControls().skipToPrevious();
                    break;
                case R.id.button_play:
                    if (mIsPlaying) {
                        mMediaBrowserHelper.getTransportControls().pause();
                    } else {
                        mMediaBrowserHelper.getTransportControls().play();
                    }
                    break;
                case R.id.button_next:
                    mMediaBrowserHelper.getTransportControls().skipToNext();
                    break;
            }
        }
    }

    /**
     * Customize the connection to our {@link android.support.v4.media.MediaBrowserServiceCompat}
     * and implement our app specific desires.
     */
    private class MediaBrowserConnection extends MediaBrowserHelper {
        private MediaBrowserConnection(Context context) {
            super(context, MusicService.class);
        }

        @Override
        protected void onConnected(@NonNull MediaControllerCompat mediaController) {
            mSeekBarAudio.setMediaController(mediaController);
        }

        @Override
        protected void onChildrenLoaded(@NonNull String parentId,
                                        @NonNull List<MediaBrowserCompat.MediaItem> children) {
            super.onChildrenLoaded(parentId, children);

            final MediaControllerCompat mediaController = getMediaController();

            // Queue up all media items for this simple sample.
            for (final MediaBrowserCompat.MediaItem mediaItem : children) {
                mediaController.addQueueItem(mediaItem.getDescription());
            }

            // Call prepare now so pressing play just works.
            mediaController.getTransportControls().prepare();
        }
    }

    /**
     * Implementation of the {@link MediaControllerCompat.Callback} methods we're interested in.
     * <p>
     * Here would also be where one could override
     * {@code onQueueChanged(List<MediaSessionCompat.QueueItem> queue)} to get informed when items
     * are added or removed from the queue. We don't do this here in order to keep the UI
     * simple.
     */
    private class MediaBrowserListener extends MediaControllerCompat.Callback {
        @Override
        public void onPlaybackStateChanged(PlaybackStateCompat playbackState) {
            mIsPlaying = playbackState != null &&
                    playbackState.getState() == PlaybackStateCompat.STATE_PLAYING;
            mMediaControlsImage.setPressed(mIsPlaying);
        }

        @Override
        public void onMetadataChanged(MediaMetadataCompat mediaMetadata) {
            if (mediaMetadata == null) {
                return;
            }
            mTitleTextView.setText(
                    mediaMetadata.getString(MediaMetadataCompat.METADATA_KEY_TITLE));
            mArtistTextView.setText(
                    mediaMetadata.getString(MediaMetadataCompat.METADATA_KEY_ARTIST));
            mAlbumArt.setImageBitmap(MusicLibrary.getAlbumBitmap(
                    MainActivity.this,
                    mediaMetadata.getString(MediaMetadataCompat.METADATA_KEY_MEDIA_ID)));
        }

        @Override
        public void onSessionDestroyed() {
            super.onSessionDestroyed();
        }

        @Override
        public void onQueueChanged(List<MediaSessionCompat.QueueItem> queue) {
            super.onQueueChanged(queue);
        }
    }
}