Android学习笔记（十五）-简易视频播放器

在Android中播放视频用到的也是MediaPlayer，展示视频通常使用SurfaceView控件。

在main.xml布局文件添加用于视频画面绘制的SurfaceView 控件：

MeidaPlayer播放视频相关API使用方法：

SurfaceView surfaceView = (SurfaceView)this.findViewById(R.id.surfaceView);surfaceView.getHolder().setFixedSize(176, 144);  //设置分辨率/*下面设置Surface不维护自己的缓冲区，而是等待屏幕的渲染引擎将内容推送到用户面前*/surfaceView.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);MediaPlayer mediaPlayer = new MediaPlayer();mediaPlayer.reset();//重置为初始状态mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);/* 设置Video影片以SurfaceHolder播放 */mediaPlayer.setDisplay(surfaceView.getHolder());mediaPlayer.setDataSource("/mnt/sdcard/oppo.mp4");mediaPlayer.prepare();//缓冲 mediaPlayer.start();//播放mediaPlayer.pause();//暂停播放mediaPlayer.start();//恢复播放mediaPlayer.stop();//停止播放mediaPlayer.release();//释放资源

下面介绍一个播放视频的简易例子，在模拟器上运行时最好用2.1, 2.1以后的模拟器播放视频时会有问题，视频播放同样需要处理一些来电类的情况，需要覆写Activity生命周期里的几个方法,需要注意的是，当Surface控件被其他Activity遮挡住是，会被销毁，所以需要为他写一个回调函数，否则当当前Activity被其他Activity打断后，又回到当前Activity是，视频播放界面会是黑屏。

详细代码：

布局文件layout/main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:background="#ffffff"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    ><TextView      android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="@string/filename"    />        <EditText    android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="oppo.mp4"    android:id="@+id/filename"    />    <LinearLayout    android:orientation="horizontal"    android:layout_width="fill_parent"    android:layout_height="wrap_content"    >    <ImageButton     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:src="@drawable/play"    android:id="@+id/play"    /> <ImageButton     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:src="@drawable/pause"    android:id="@+id/pause"    />    <ImageButton     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:src="@drawable/reset"    android:id="@+id/reset"    /> <ImageButton     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:src="@drawable/stop"    android:id="@+id/stop"    /></LinearLayout><SurfaceView android:layout_width="fill_parent"     android:layout_height="240dip"     android:id="@+id/surfaceView"    /></LinearLayout>

数据文件values/strings.xml

<?xml version="1.0" encoding="utf-8"?><resources>    <string name="hello">Hello World, PlayActivity!</string>    <string name="app_name">视频播放器</string>    <string name="filename">视频文件</string>    <string name="sdcarderror">SDCard不存在</string></resources>

Activity

package com.android.media;import java.io.File;import java.io.IOException;import android.app.Activity;import android.media.AudioManager;import android.media.MediaPlayer;import android.os.Bundle;import android.os.Environment;import android.util.Log;import android.view.SurfaceHolder;import android.view.SurfaceView;import android.view.View;import android.widget.EditText;import android.widget.ImageButton;import android.widget.Toast;public class PlayerActivity extends Activity {private static final String TAG = "PlayerActivity";    private EditText filenameText;    private MediaPlayer mediaPlayer;    private SurfaceView surfaceView;    private String filename;    private int position;        @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);                filenameText = (EditText)this.findViewById(R.id.filename);                surfaceView = (SurfaceView) this.findViewById(R.id.surfaceView);        surfaceView.getHolder().setFixedSize(176, 144);//设置分辨率        surfaceView.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);        surfaceView.getHolder().addCallback(new SurfaceCallback());        mediaPlayer = new MediaPlayer();        ButtonClickListener listener = new ButtonClickListener();        ImageButton playButton = (ImageButton)this.findViewById(R.id.play);        ImageButton pauseButton = (ImageButton)this.findViewById(R.id.pause);        ImageButton resetButton = (ImageButton)this.findViewById(R.id.reset);        ImageButton stopButton = (ImageButton) this.findViewById(R.id.stop);        playButton.setOnClickListener(listener);        pauseButton.setOnClickListener(listener);        resetButton.setOnClickListener(listener);        stopButton.setOnClickListener(listener);    }        private final class SurfaceCallback implements SurfaceHolder.Callback{@Overridepublic void surfaceCreated(SurfaceHolder holder) {if(position>0 && filename!=null){try {play();mediaPlayer.seekTo(position);position = 0;} catch (IOException e) {Log.e(TAG, e.toString());}}}@Overridepublic void surfaceChanged(SurfaceHolder holder, int format, int width,int height) {}@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {if(mediaPlayer.isPlaying()){position = mediaPlayer.getCurrentPosition();mediaPlayer.stop();}}        }private final class ButtonClickListener implements View.OnClickListener{@Overridepublic void onClick(View v) {if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){Toast.makeText(PlayerActivity.this, R.string.sdcarderror, 1).show();return;}filename = filenameText.getText().toString();try {switch (v.getId()) {case R.id.play:play();break;case R.id.pause:if(mediaPlayer.isPlaying()){mediaPlayer.pause();}else{mediaPlayer.start();}break;case R.id.reset:if(mediaPlayer.isPlaying()){mediaPlayer.seekTo(0);}else{play();}break;case R.id.stop:if(mediaPlayer.isPlaying()) mediaPlayer.stop();break;}} catch (Exception e) {Log.e(TAG, e.toString());}}    }private void play() throws IOException {File videoFile = new File(Environment.getExternalStorageDirectory(), filename);mediaPlayer.reset();//重置为初始状态mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);/* 设置Video影片以SurfaceHolder播放 */mediaPlayer.setDisplay(surfaceView.getHolder());mediaPlayer.setDataSource(videoFile.getAbsolutePath());mediaPlayer.prepare();//缓冲mediaPlayer.start();//播放}}

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