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：
<SurfaceView android:layout_width="fill_parent"android:layout_height="240dip"android:id="@+id/surfaceView"/>
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{
@Override
public void surfaceCreated(SurfaceHolder holder) {
if(position>0 && filename!=null){
try {
play();
mediaPlayer.seekTo(position);
position = 0;
} catch (IOException e) {
Log.e(TAG, e.toString());
}
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
if(mediaPlayer.isPlaying()){
position = mediaPlayer.getCurrentPosition();
mediaPlayer.stop();
}
}
}
private final class ButtonClickListener implements View.OnClickListener{
@Override
public 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
}
}