Android学习（16）-音频和视频

音频：

Android里面的思路：创建一个MediaPlayer对象，调用setDataSource方法来设置音频文件的路径，调用prepare方法使MediaPlayer进去到准备状态，调用start开始，pause暂停，reset方法停止播放。

视频的套路和音频一直。此处的功能主要是对已有音频和视频的操作：

其布局代码：

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/musicStart"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="音频开始" />

    <Button
        android:id="@+id/musicPause"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button1"
        android:layout_alignBottom="@+id/button1"
        android:layout_centerHorizontal="true"
        android:text="音频暂停" />

    <Button
        android:id="@+id/videoStart"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button1"
        android:layout_below="@+id/button1"
        android:layout_marginTop="108dp"
        android:text="视频开始" />

    <VideoView
        android:id="@+id/videoView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/videoStart"
        android:layout_alignParentBottom="true"
        android:layout_below="@+id/videoStart" />

    <Button
        android:id="@+id/videoPause"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/videoStop"
        android:layout_alignBottom="@+id/videoStop"
        android:layout_alignParentRight="true"
        android:text="视频暂停" />

    <Button
        android:id="@+id/videoStop"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/videoView"
        android:layout_toLeftOf="@+id/videoPause"
        android:text="视频停止" />

    <Button
        android:id="@+id/musicStop"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/musicPause"
        android:layout_alignBottom="@+id/musicPause"
        android:layout_alignLeft="@+id/videoPause"
        android:text="音频停止" />

</RelativeLayout>

其活动代码如下：

public class MainActivity extends Activity implements OnClickListener{

	//音频相关
	private Button musicStart;
	private Button musicPause;
	private Button musicStop;
	private MediaPlayer mediaPlayer = new MediaPlayer();
	
	
	//视频相关
	private Button videoStart;
	private Button videoPause;
	private Button videoStop;
	private VideoView videoView;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		//音频相关
		musicStart = (Button)findViewById(R.id.musicStart);
		musicPause = (Button)findViewById(R.id.musicPause);
		musicStop = (Button)findViewById(R.id.musicStop);
		musicStart.setOnClickListener(this);
		musicPause.setOnClickListener(this);
		musicStop.setOnClickListener(this);
		initMediaPlayer();//初始化音频
		
		//视频相关
		videoStart = (Button)findViewById(R.id.videoStart);
		videoPause = (Button)findViewById(R.id.videoPause);
		videoStop = (Button)findViewById(R.id.videoStop);
		videoView = (VideoView)findViewById(R.id.videoView);
		videoStart.setOnClickListener(this);
		videoPause.setOnClickListener(this);
		videoStop.setOnClickListener(this);
		initVideoPath();
		
	}
	
	//初始化音频
	private void initMediaPlayer(){
		try {
			File file = new File(Environment.getExternalStorageDirectory(),"music.mp3"); //音频文件
			mediaPlayer.setDataSource(file.getPath());
			mediaPlayer.prepare();
		} catch (Exception e) {
			e.printStackTrace();
		} 
	}
	
	//初始化视频
	private void initVideoPath(){
		File file = new File(Environment.getExternalStorageDirectory(),"movie.3gp"); //视频文件
		videoView.setVideoPath(file.getPath());
	}
	
	//对于很多按钮  采用这种事件处理方式  比较好
	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.musicStart:
			if(!mediaPlayer.isPlaying()){
				mediaPlayer.start();
			}
			break;
		case R.id.musicPause:
			if(!mediaPlayer.isPlaying()){
				mediaPlayer.pause();
			}
			break;
		case R.id.musicStop:
			if(!mediaPlayer.isPlaying()){
				mediaPlayer.reset();
				initMediaPlayer();
			}
			break;
		case R.id.videoStart:
			if(!videoView.isPlaying()){
				videoView.start();
			}
			break;
		case R.id.videoPause:
			if(!videoView.isPlaying()){
				videoView.pause();
			}
			break;
		case R.id.videoStop:
			if(!videoView.isPlaying()){
				videoView.resume();
			}
			break;
		default:
			break;
		}
		
	}

	//此处比较周到
	public void onDestroy(){
		super.onDestroy();
		if(mediaPlayer != null){
			mediaPlayer.stop();
			mediaPlayer.release();
		}
		if(videoView != null){
			videoView.suspend();
		}
	}
	

}