概述

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。

涉及知识点

MediaPlayer 可以用来控制audio/video文件或流播放的类。通过此类，可以方便的控制音频/视频文件的播放，暂停和停止等操作。

Uri 统一资源标识符(Uniform Resource Identifier，或URI)是一个用于标识某一互联网资源名称的字符串。

VideoView 自带的一种播放视频的组件。

SurfaceView 可以通过后台绘制显示的视图组件。

Activity中播放音频

页面上播放音频文件，步骤如下：

1. 准备资源文件，并播放

1 privateMediaPlayer mMediaPlayer;2

3 /**

4 * 开始5 *@paramv6 */

7 public voidbn_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 voidready(){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();//Prepared

28 } 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 *@paramv4 */

5 public voidbn_pause(View v){6 if(mMediaPlayer!=null &&mMediaPlayer.isPlaying()){7 mMediaPlayer.pause();8 }9 }

3. 停止

1 /**

2 * 停止3 *@paramv4 */

5 public voidbn_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 voidonDestroy() {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:AndroidProjectDemoMediaappsrcmainesawA2012.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 underscore5 */

6 private voidready2(){7 if(mMediaPlayer==null){8 mMediaPlayer= MediaPlayer.create(this,R.raw.ab2012);9 }10 }

通过服务来播放音频

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 extendsService {2

3 privateMediaPlayer mMediaPlayer;4

5 privateOperatorReceiver mReceiver;6

7 publicAudioService() {8 }9

10 @Override11 public voidonCreate() {12 super.onCreate();13 mMediaPlayer=newMediaPlayer();14 mReceiver=newOperatorReceiver();15 IntentFilter filter=new IntentFilter("operator.receiver");16 registerReceiver(mReceiver,filter);17 }18

19 @Override20 publicIBinder onBind(Intent intent) {21 return null;22 }23

24 @Override25 public int onStartCommand(Intent intent, int flags, intstartId) {26 Log.i("TAG", "onStartCommand: ----ready ");27 ready();28 return super.onStartCommand(intent, flags, startId);29 }30

31 @Override32 public voidonDestroy() {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 voidstart(){45 mMediaPlayer.start();46 }47

48 private voidpause(){49 mMediaPlayer.pause();50 }51

52 private voidstop(){53 mMediaPlayer.stop();54 ready();55 }56

57 private voidready(){58 mMediaPlayer.reset();59 try{60 String filePath= Environment.getExternalStorageDirectory()+"/ab2012.mp3";61 Log.i("TAG", "ready: "+filePath);62 File file=newFile(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 extendsBroadcastReceiver5 {6 @Override7 public voidonReceive(Context context, Intent intent) {8 int cmd=intent.getIntExtra("cmd",-1);9 Log.i("TAG", "onReceive: "+cmd);10 switch(cmd){11 caseTools.PLAY:12 start();13 break;14 caseTools.PAUSE:15 pause();16 break;17 caseTools.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 *@paramv4 */

5 public voidbn_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 *@paramv15 */

16 public voidbn_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 *@paramv25 */

26 public voidbn_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

3 android:enabled="true"

4 android:exported="true">

5

通过VideoView来播放视频

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 privateVideoView mVideoView;2 @Override3 protected voidonCreate(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 Controller

16 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(newMediaPlayer.OnCompletionListener() {23 @Override24 public voidonCompletion(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

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 voidbn_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 voidbn_pause(View view){2 if(mMediaPlayer.isPlaying()){3 mMediaPlayer.pause();4 }5 }6

7 public voidbn_stop(View view){8 if(mMediaPlayer.isPlaying()){9 mMediaPlayer.stop();10 }11 }

3. 资源释放

1 @Override2 protected voidonDestroy() {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 }

权限设置

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

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备注

合抱之木，生于毫末；九层之台，起于垒土；千里之行，始于足下。