本文利用SurfaceView來實現視頻的播放

本文地址：http://www.cnblogs.com/wuyudong/p/5851156.html，轉載請注明源地址。

在main.xml布局文件添加用于視頻畫面繪制的SurfaceView 控件：

<SurfaceView android:layout_width="fill_parent" android:layout_height="240dip" android:id="@+id/surfaceView" />

項目布局設計：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"tools:context=".MainActivity" ><EditTextandroid:id="@+id/et_path"android:layout_width="fill_parent"android:layout_height="wrap_content"android:hint="請輸入視頻文件的路徑" /><LinearLayoutandroid:layout_width="fill_parent"android:layout_height="wrap_content"android:orientation="horizontal" ><Buttonandroid:id="@+id/bt_play"android:layout_width="0dip"android:layout_height="wrap_content"android:layout_weight="1"android:text="播放" /><Buttonandroid:id="@+id/bt_pause"android:layout_width="0dip"android:layout_height="wrap_content"android:layout_weight="1"android:text="暫停" /><Buttonandroid:id="@+id/bt_replay"android:layout_width="0dip"android:layout_height="wrap_content"android:layout_weight="1"android:text="重播" /><Buttonandroid:id="@+id/bt_stop"android:layout_width="0dip"android:layout_height="wrap_content"android:layout_weight="1"android:text="停止" /></LinearLayout><SurfaceView android:id="@+id/sv"android:layout_width="fill_parent"android:layout_height="fill_parent"/></LinearLayout>

大部分代碼和《Android 多媒體播放API簡介》中的完全一樣，修改一點點代碼即可：

public class MainActivity extends Activity implements OnClickListener {private EditText et_path;private Button bt_play, bt_replay, bt_pause, bt_stop;private SurfaceView sv;private MediaPlayer mediaPlayer;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);sv = (SurfaceView)findViewById(R.id.sv);et_path = (EditText) findViewById(R.id.et_path);bt_play = (Button) findViewById(R.id.bt_play);bt_replay = (Button) findViewById(R.id.bt_replay);bt_pause = (Button) findViewById(R.id.bt_pause);bt_stop = (Button) findViewById(R.id.bt_stop);bt_pause.setOnClickListener(this);bt_play.setOnClickListener(this);bt_replay.setOnClickListener(this);bt_stop.setOnClickListener(this);}@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.bt_play:play();break;case R.id.bt_replay:replay();break;case R.id.bt_stop:stop();break;case R.id.bt_pause:pause();break;default:break;}}/*** 暫停音樂*/private void pause() {if ("繼續".equals(bt_pause.getText().toString().trim())) {mediaPlayer.start();bt_pause.setText("暫停");return;}if (mediaPlayer != null && mediaPlayer.isPlaying()) {mediaPlayer.pause();bt_pause.setText("繼續");return;}}/*** 重新播放*/private void replay() {if (mediaPlayer != null && mediaPlayer.isPlaying()) {mediaPlayer.seekTo(0);return;}play();}/*** 停止播放音樂*/private void stop() {if (mediaPlayer != null && mediaPlayer.isPlaying()) {mediaPlayer.stop();mediaPlayer.release(); // 記得釋放資源mediaPlayer = null;bt_play.setEnabled(true);}}/*** 播放音樂*/private void play() {String path = et_path.getText().toString().trim();File file = new File(path);if (file.exists() && file.length() > 0) {try {mediaPlayer = new MediaPlayer();mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);/* 設置Video影片以SurfaceHolder播放 */mediaPlayer.setDisplay(sv.getHolder());mediaPlayer.setDataSource(path);mediaPlayer.prepare(); // might take long! (for buffering, etc) mediaPlayer.start();mediaPlayer.setOnCompletionListener(new OnCompletionListener() {@Overridepublic void onCompletion(MediaPlayer mp) {bt_play.setEnabled(true);}} );bt_play.setEnabled(false);} catch (Exception e) {Toast.makeText(this, "播放失敗", 0).show();e.printStackTrace();}} else {Toast.makeText(this, "文件不存在", 0).show();}}}

運行項目效果如下：

但是上面的代碼有點問題，那就是當點擊home或返回屏幕主界面后，在回到播放頁面，視頻黑屏

原因：

SurfaceView內部維護雙緩沖，消耗內存資源

如果發現當前SurfaceView 用戶可見的時候，創建SurfaceView的holder

如果SurfaceView變成用戶不可見的時候 ?銷毀SurfaceView的holder

為了觀察SurfaceView的生命周期，可以添加下面的代碼進行打印追蹤：

sv.getHolder().addCallback(new Callback() {@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {System.out.println("holder被銷毀了");}@Overridepublic void surfaceCreated(SurfaceHolder holder) {System.out.println("holder被創建了");}@Overridepublic void surfaceChanged(SurfaceHolder holder, int format, int width,int height) {System.out.println("holder的大小變化了");}});}

logcat中打印下面的信息：

09-07 11:36:34.613: I/System.out(28858): holder被創建了
09-07 11:36:34.623: I/System.out(28858): holder的大小變化了

返回主界面

09-07 11:39:08.245: I/System.out(28858): holder被銷毀了

再次回到視頻界面

09-07 11:39:39.405: I/System.out(28858): holder被創建了
09-07 11:39:39.405: I/System.out(28858): holder的大小變化了

可以看到，每次回到視頻界面，holder都會被重新創建

修改后的代碼如下：

public class MainActivity extends Activity implements OnClickListener {private EditText et_path;private Button bt_play, bt_replay, bt_pause, bt_stop;private SurfaceView sv;private MediaPlayer mediaPlayer;private int currentPosition;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);sv = (SurfaceView) findViewById(R.id.sv);et_path = (EditText) findViewById(R.id.et_path);bt_play = (Button) findViewById(R.id.bt_play);bt_replay = (Button) findViewById(R.id.bt_replay);bt_pause = (Button) findViewById(R.id.bt_pause);bt_stop = (Button) findViewById(R.id.bt_stop);bt_pause.setOnClickListener(this);bt_play.setOnClickListener(this);bt_replay.setOnClickListener(this);bt_stop.setOnClickListener(this);sv.getHolder().addCallback(new Callback() {@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {System.out.println("holder被銷毀了");if (mediaPlayer != null && mediaPlayer.isPlaying()) {currentPosition = mediaPlayer.getCurrentPosition();stop();}}@Overridepublic void surfaceCreated(SurfaceHolder holder) {System.out.println("holder被創建了");if (currentPosition > 0) {play(currentPosition);}}@Overridepublic void surfaceChanged(SurfaceHolder holder, int format,int width, int height) {System.out.println("holder的大小變化了");}});}@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.bt_play:play(0);break;case R.id.bt_replay:replay();break;case R.id.bt_stop:stop();break;case R.id.bt_pause:pause();break;default:break;}}/*** 暫停音樂*/private void pause() {if ("繼續".equals(bt_pause.getText().toString().trim())) {mediaPlayer.start();bt_pause.setText("暫停");return;}if (mediaPlayer != null && mediaPlayer.isPlaying()) {mediaPlayer.pause();bt_pause.setText("繼續");return;}}/*** 重新播放*/private void replay() {if (mediaPlayer != null && mediaPlayer.isPlaying()) {mediaPlayer.seekTo(0);return;}play(0);}/*** 停止播放音樂*/private void stop() {if (mediaPlayer != null && mediaPlayer.isPlaying()) {mediaPlayer.stop();mediaPlayer.release(); // 記得釋放資源mediaPlayer = null;bt_play.setEnabled(true);}}/*** 播放音樂*/private void play(final int currentPosition) {String path = et_path.getText().toString().trim();File file = new File(path);if (file.exists() && file.length() > 0) {try {mediaPlayer = new MediaPlayer();mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);/* 設置Video影片以SurfaceHolder播放 */mediaPlayer.setDisplay(sv.getHolder());mediaPlayer.setDataSource(path);mediaPlayer.prepare(); // might take long! (for buffering, etc) mediaPlayer.start();mediaPlayer.setOnPreparedListener(new OnPreparedListener() {@Overridepublic void onPrepared(MediaPlayer mp) {mediaPlayer.seekTo(currentPosition);}});mediaPlayer.setOnCompletionListener(new OnCompletionListener() {@Overridepublic void onCompletion(MediaPlayer mp) {bt_play.setEnabled(true);}});bt_play.setEnabled(false);} catch (Exception e) {Toast.makeText(this, "播放失敗", 0).show();e.printStackTrace();}} else {Toast.makeText(this, "文件不存在", 0).show();}}}

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