mediarecorder学习，android4.0后mediarecorder start failed的原因

1、因为Api的兼容问题，，mediarecorder的启动方式也不同了，因为我看的视频是api 8的因此无法启动，在网上查了了好多资料都没说清楚，最终还是去官网查看才得以实现：

官网实现的方式：

我实现的demo，希望给跟我一样的初学者一点帮助，少走弯路：

需要权限：

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<uses-permission android:name="android.permission.RECORD_AUDIO"/>

main_xml文件

<LinearLayout
         xmlns:android="http://schemas.android.com/apk/res/android"
    	xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical"
        tools:context="com.example.mycamera.MainActivity$PlaceholderFragment"
         >
    <SurfaceView
        android:layout_weight="100"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
       	android:id="@+id/camera"
		 />
    <RelativeLayout 
        
        android:layout_weight="0"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        >
	<Button 
	    android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="开始录制"
        android:layout_alignParentRight="true"
        android:id="@+id/pz"
        android:onClick="luxiang"
	    />
	<Button 
	    android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="停止"
        android:id="@+id/dj"
        android:layout_toLeftOf="@+id/pz"
        android:onClick="tingzhi"
	    />
	</RelativeLayout>
	</LinearLayout>

　　

public class MainActivity extends ActionBarActivity {//ActionBarActivity

	private SurfaceView sv;
	private SurfaceHolder holder;
	private Camera mCamera;
	private MediaRecorder recorder;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);//去掉信息栏
        setContentView(R.layout.activity_main);
        sv=(SurfaceView) findViewById(R.id.camera);
        holder=sv.getHolder();
        holder.addCallback(new MyCallback());
        
    }
    
    public void tingzhi(View v)
    {
    	recorder.release();
    	recorder=null;
    }
    public void luxiang(View v) throws IOException
    {
    	
    	
    	recorder=new MediaRecorder();
    	recorder.reset();
    	mCamera.unlock();
    	recorder.setCamera(mCamera);
    	recorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);//设定音源摄像机
    	recorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
    	recorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH));//指定录像的质量
    	recorder.setOutputFile("data/data/musics/hahagaga.3gp");  
        // 第5步:指定预览输出  
    	recorder.setPreviewDisplay(holder.getSurface()); 
    	try {  
            recorder.prepare();  
        } catch (Exception e) {  
            recorder.release();  
        } 
    	recorder.start();
    	
//    	recorder=new MediaRecorder();
//    	recorder.reset();
//    	recorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
//    	recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
//    	recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
////    	video-size-values=640x480,576x432,480x320,432x240,384x288,352x288,320x240,240x160,176x144
////		preview-size-values=640x480,576x432,480x320,432x240,384x288,352x288,320x240,240x160,176x144   
//    	recorder.setVideoSize(576, 432);
//    	recorder.setVideoFrameRate(5);
//    	recorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
//    	recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
//    	recorder.setOutputFile("data/data/musics/hahagaga.3gp");
//    	recorder.setPreviewDisplay(holder.getSurface());
//    	try{
//    	recorder.prepare();
//    	}catch(Exception e)
//    	{
//    		System.out.println("准备失败");
//    		e.printStackTrace();
//    	}
//    	try{
//    		recorder.start();
//    	}catch(Exception e)
//    	{
//    		System.out.println("开始失败");
//    		e.printStackTrace();
//    	}
    	
    }

    class MyPictureCallback implements  PictureCallback
    {
		@Override
		public void onPictureTaken(byte[] data, Camera camera) {
			//dada就是拍照后压缩的数据
			File image=new File(Environment.getDataDirectory(),"zp.jpg");
			FileOutputStream out=null;
			try {
				 out=new FileOutputStream(image);
				out.write(data);
				out.flush();
				out.close();
			} catch (Exception e) {
				e.printStackTrace();
				Toast.makeText(MainActivity.this, "保存照片失败！", Toast.LENGTH_LONG).show();
			}
			finally
			{
//				mCamera.startPreview();
			}
		}
    	
    }
    
    
class MyCallback implements Callback
{

	@Override
	public void surfaceCreated(SurfaceHolder holder) {
		
		//录像
    	mCamera=Camera.open();
    	try {
			mCamera.setPreviewDisplay(holder);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    	mCamera.startPreview();
		
	}

	@Override
	public void surfaceChanged(SurfaceHolder holder, int format, int width,
			int height) {
	}

	@Override
	public void surfaceDestroyed(SurfaceHolder holder) {
//		mCamera.release();
//		mCamera=null;
	}
	
}
}