Android调用系统摄像头--使用MediaRecorder--2--使用MediaRecorder进行录制

准备好了预览(preview)之后，就可以使用MediaRecorder进行视频录制了，付上录制部分的代码

publicclassAndroidCameraActivityextendsActivity{
privatestaticfinalStringTAG="TAG-AndroidCameraActivity";

publicstaticfinalintMEDIA_TYPE_IMAGE=1;
publicstaticfinalintMEDIA_TYPE_VIDEO=2;

privateCameramCamera;
privateCameraPreviewmPreview;


privateButtoncaptureButton;

privateMediaRecordermMediaRecorder;

privatebooleanisRecording=false;

@Override
publicvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

//创建Camera实例
mCamera=getCameraInstance();

//创建Previewview并将其设为activity中的内容
mPreview=newCameraPreview(this,mCamera);
FrameLayoutpreview=(FrameLayout)findViewById(R.id.camera_preview);
preview.addView(mPreview);

//为Capture按钮加入listener,拍摄视频
captureButton=(Button)findViewById(R.id.button_capture);
captureButton.setOnClickListener(newView.OnClickListener(){

@Override
publicvoidonClick(Viewv){
if(isRecording){
//停止录像，释放camera
mMediaRecorder.stop();
releaseMediaRecorder();

mCamera.lock();

//通知用户录像已停止
captureButton.setText("开始录像");

isRecording=false;
}else{
//初始化视频camera
if(prepareVideoRecorder()){
mMediaRecorder.start();

//通知用户录像已开始
captureButton.setText("停止录像");

isRecording=true;
}else{
//准备未能完成，释放camera
releaseMediaRecorder();
}
}
}
});
}

@Override
protectedvoidonPause(){
super.onPause();
//如果正在使用MediaRecorder，首先需要释放它。
releaseMediaRecorder();
//在暂停事件中立即释放摄像头
releaseCamera();
}

privatevoidreleaseMediaRecorder(){
if(mMediaRecorder!=null){
//清除recorder配置
mMediaRecorder.reset();
//释放recorder对象
mMediaRecorder.release();

mMediaRecorder=null;
//为后续使用锁定摄像头
mCamera.lock();
}
}

privatevoidreleaseCamera(){
if(mCamera!=null){
//为其它应用释放摄像头
mCamera.release();
mCamera=null;
}
}

privatebooleanprepareVideoRecorder(){

mMediaRecorder=newMediaRecorder();

//第1步:解锁并将摄像头指向MediaRecorder
mCamera.unlock();
mMediaRecorder.setCamera(mCamera);

//第2步:指定源
mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);

//第3步:指定CamcorderProfile(需要APILevel8以上版本)
//mMediaRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH));
//第3步:设置输出格式和编码格式(针对低于APILevel8版本)
mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT);
mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);


//第4步:指定输出文件
mMediaRecorder.setOutputFile(getOutputMediaFile(MEDIA_TYPE_VIDEO).toString());

//第5步:指定预览输出
mMediaRecorder.setPreviewDisplay(mPreview.getHolder().getSurface());

//第6步:根据以上配置准备MediaRecorder
try{
mMediaRecorder.prepare();
}catch(IllegalStateExceptione){
Log.d(TAG,"IllegalStateExceptionpreparingMediaRecorder:"+e.getMessage());
releaseMediaRecorder();
returnfalse;
}catch(IOExceptione){
Log.d(TAG,"IOExceptionpreparingMediaRecorder:"+e.getMessage());
releaseMediaRecorder();
returnfalse;
}
returntrue;
}

privateCameragetCameraInstance(){
Camerac=null;

try{
//获取Camera实例
c=Camera.open();
}catch(Exceptione){
//摄像头不可用（正被占用或不存在）
}
//不可用则返回null
returnc;
}

privateFilegetOutputMediaFile(inttype){
//......生成媒体文件，如xxx.mp4......
}

privatebooleancheckCameraHardware(Contextcontext){
if(context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
//摄像头存在
returntrue;
}else{
//摄像头不存在
returnfalse;
}
}
}

根据Android官方文档，在使用MediaRecorder进行视频录制的时候一定要严格遵循上面的顺序，否则会报错

在API里到处是“if it is called before setOutputFormat() or after prepare() ”因此一定要严格的按照顺序来进行摄像头操作