Android多媒体框架支持各种常见的媒体类型，可以很容易地将音频、视频和图像集成到App中。通过MediaPlayer Api，可以从应用程序资源（RAW）、文件系统或网络上数据流资源来播放音频或视频。本文演示了如何通过Api播放音频和视频文件，来获得良好性能和愉快的用户体验，仅供学习分享使用，如有不足之处，还请指正。
页面上播放音频文件，步骤如下：
1. 准备资源文件，并播放
1 private MediaPlayer mMediaPlayer; 2 3 /** 4 * 开始 5 * @param v 6 */ 7 public void bn_start(View v){ 8 if(mMediaPlayer==null) { 9 ready();10 }11 mMediaPlayer.start();12 }13 14 /**15 * 创建MediaPlayer并到prepare状态16 */17 private void ready(){18 if(mMediaPlayer==null){19 mMediaPlayer=new MediaPlayer();//Idle20 //Log.i("TAG", "ready: "+filePath);21 File file=new File(Environment.getExternalStorageDirectory(),"goldfallen.mp3");22 Log.i("TAG", "ready: "+file.getPath());23 Log.i("TAG", "ready: "+file.exists());24 Uri uri= Uri.fromFile(file);25 try {26 mMediaPlayer.setDataSource(AudioActivity.this,uri);27 mMediaPlayer.prepare();//Prepared28 } catch (IOException e) {29 Log.i("TAG", "ready: "+ e.getMessage());30 e.printStackTrace();31 }32 }33 }
2. 暂停播放
1 /**2 * 暂停3 * @param v4 */5 public void bn_pause(View v){6 if(mMediaPlayer!=null && mMediaPlayer.isPlaying()){7 mMediaPlayer.pause();8 }9 }
3. 停止
1 /** 2 * 停止 3 * @param v 4 */ 5 public void bn_stop(View v){ 6 if(mMediaPlayer!=null && mMediaPlayer.isPlaying()){ 7 mMediaPlayer.stop(); 8 mMediaPlayer.release(); 9 mMediaPlayer=null;10 }11 }
4. 释放资源（当页面销毁时，播放资源也要同时释放）
1 @Override2 protected void onDestroy() {3 if(mMediaPlayer!=null && mMediaPlayer.isPlaying()){4 mMediaPlayer.stop();5 mMediaPlayer.release();6 mMediaPlayer=null;7 }8 super.onDestroy();9 }
5. 通过静态函数创建对象
1 /** 2 * D:\Android\Project\DemoMedia\app\src\main\res\raw\A2012.mp3: 3 * Error: ‘A‘ is not a valid file-based resource name character: 4 * File-based resource names must contain only lowercase a-z, 0-9, or underscore 5 */ 6 private void ready2(){ 7 if(mMediaPlayer==null){ 8 mMediaPlayer= MediaPlayer.create(this,R.raw.ab2012); 9 }10 }
当页面关闭时，音频文件还可以在后台播放。步骤如下：
1. 定义后台服务，当服务启动时，创建MediaPlayer对象，并注册服务接收对象。
1 public class AudioService extends Service { 2 3 private MediaPlayer mMediaPlayer; 4 5 private OperatorReceiver mReceiver; 6 7 public AudioService() { 8 } 9 10 @Override11 public void onCreate() {12 super.onCreate();13 mMediaPlayer=new MediaPlayer();14 mReceiver=new OperatorReceiver();15 IntentFilter filter=new IntentFilter("operator.receiver");16 registerReceiver(mReceiver,filter);17 }18 19 @Override20 public IBinder onBind(Intent intent) {21 return null;22 }23 24 @Override25 public int onStartCommand(Intent intent, int flags, int startId) {26 Log.i("TAG", "onStartCommand: ----ready ");27 ready();28 return super.onStartCommand(intent, flags, startId);29 }30 31 @Override32 public void onDestroy() {33 if(mMediaPlayer!=null && mMediaPlayer.isPlaying()){34 mMediaPlayer.stop();35 }36 if(mMediaPlayer!=null){37 mMediaPlayer.release();38 mMediaPlayer=null;39 }40 unregisterReceiver(mReceiver);41 super.onDestroy();42 }43 44 private void start(){45 mMediaPlayer.start();46 }47 48 private void pause(){49 mMediaPlayer.pause();50 }51 52 private void stop(){53 mMediaPlayer.stop();54 ready();55 }56 57 private void ready(){58 mMediaPlayer.reset();59 try {60 String filePath= Environment.getExternalStorageDirectory()+"/ab2012.mp3";61 Log.i("TAG", "ready: "+filePath);62 File file=new File(filePath);63 if(file.exists()) {64 mMediaPlayer.setDataSource(filePath);65 mMediaPlayer.prepare();66 }else{67 Log.i("TAG", "ready: 文件不存在 ");68 }69 } catch (IOException e) {70 Log.i("TAG", "ready: "+e.getMessage());71 e.printStackTrace();72 }73 }74 }
2. 操作接收者定义如下：
1 /** 2 * 操作接收器 3 */ 4 class OperatorReceiver extends BroadcastReceiver 5 { 6 @Override 7 public void onReceive(Context context, Intent intent) { 8 int cmd=intent.getIntExtra("cmd",-1); 9 Log.i("TAG", "onReceive: "+cmd);10 switch (cmd){11 case Tools.PLAY:12 start();13 break;14 case Tools.PAUSE:15 pause();16 break;17 case Tools.STOP:18 stop();19 break;20 default:21 start();22 break;23 24 }25 }26 }
3. 启动服务
1 Intent intent =new Intent(this,AudioService.class);2 startService(intent);
4. 前台Activity通过发送广播命令进行控制音频的播放与暂停
1 /** 2 * 开始 3 * @param v 4 */ 5 public void bn_start(View v){ 6 Intent intent=new Intent("operator.receiver"); 7 intent.putExtra("cmd",Tools.PLAY); 8 sendBroadcast(intent); 9 Log.i("TAG", "bn_start: "+"service");10 }11 12 /**13 * 暂停14 * @param v15 */16 public void bn_pause(View v){17 Intent intent=new Intent("operator.receiver");18 intent.putExtra("cmd",Tools.PAUSE);19 sendBroadcast(intent);20 }21 22 /**23 * 停止24 * @param v25 */26 public void bn_stop(View v){27 Intent intent=new Intent("operator.receiver");28 intent.putExtra("cmd",Tools.STOP);29 sendBroadcast(intent);30 }
5.通过后台服务的方式，需要在AndroidManifest.xml文件中进行注册
1 <service2 android:name=".AudioService"3 android:enabled="true"4 android:exported="true">5 </service>
通过VideoView进行播放视频文件，只需要设置资源URI即可，具体如下：
1 private VideoView mVideoView; 2 @Override 3 protected void onCreate(Bundle savedInstanceState) { 4 super.onCreate(savedInstanceState); 5 setContentView(R.layout.activity_video); 6 mVideoView= (VideoView) this.findViewById(R.id.vv_info); 7 //设置路径 8 File file=new File(Environment.getExternalStorageDirectory(),"DCIM/Camera/VID20190629142614.mp4"); 9 Log.i("TAG", "onCreate: "+file.getPath());10 if(!file.exists()){11 Log.i("TAG", "onCreate: 文件不存在");12 }13 Uri uri=Uri.fromFile(file);14 mVideoView.setVideoURI(uri);15 //设置Media Controller16 MediaController controller=new MediaController(this);17 mVideoView.setMediaController(controller);18 //获取焦点19 mVideoView.requestFocus();20 mVideoView.start();21 //设置播放完成事件22 mVideoView.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {23 @Override24 public void onCompletion(MediaPlayer mp) {25 Toast.makeText(VideoActivity.this, "播放完毕", Toast.LENGTH_SHORT).show();26 }27 });28 }
通过MediaPlayer来播放视频文件，然后通过SurfaceView来显示视频内容，具体步骤如下：
1.启动，通过setDisplay来设置显示内容
1 public void bn_start(View view) { 2 mMediaPlayer.reset();//到Idle状态 3 //设置路径 4 File file=new File(Environment.getExternalStorageDirectory(),"DCIM/Camera/VID20190629142614.mp4"); 5 Log.i("TAG", "onCreate: "+file.getPath()); 6 if(!file.exists()){ 7 Log.i("TAG", "onCreate: 文件不存在"); 8 } else { 9 Log.i("TAG", "onCreate: 文件存在 ");10 }11 Uri uri=Uri.fromFile(file);12 try {13 mMediaPlayer.setDataSource(this,uri);14 mMediaPlayer.setDisplay(mSurfaceView.getHolder());15 mMediaPlayer.prepare();16 mMediaPlayer.start();17 } catch (IOException e) {18 e.printStackTrace();19 }20 }
2. 暂停与停止
1 public void bn_pause(View view){ 2 if(mMediaPlayer.isPlaying()){ 3 mMediaPlayer.pause(); 4 } 5 } 6 7 public void bn_stop(View view){ 8 if(mMediaPlayer.isPlaying()){ 9 mMediaPlayer.stop();10 }11 }
3. 资源释放
1 @Override 2 protected void onDestroy() { 3 if(mMediaPlayer!=null && mMediaPlayer.isPlaying()){ 4 mMediaPlayer.stop(); 5 } 6 if(mMediaPlayer!=null){ 7 mMediaPlayer.release(); 8 mMediaPlayer=null; 9 }10 super.onDestroy();11 }
如果要播放视频，需要相应的权限设置，并在安装时获取请求权限
1 <uses-permission android:name="android.permission.INTERNET"/>2 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>3 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>4 <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
合抱之木，生于毫末；九层之台，起于垒土；千里之行，始于足下。
