为什么MediaRecorder功能不会导致ANR错误？
我开始使用Android 5.1中的MediaRecorder和MediaProjection函数来显示reord屏幕的服务，我认为代码方法1会导致应用程序不响应错误，因为它在主线程中工作。
我测试代码方法1重新编码屏幕很长时间，它不会发生“应用程序不响应错误”，为什么？ 这是否意味着MediaRecorder和MediaProjection函数在独立线程中工作？
在代码方法2中 ，我创建了一个线程来运行mRecordHelper.StartRecord（mRecordArg，resultCode，mIntent）; 但我得到的错误java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare(),为什么？
谢谢你的帮助。
呼叫代码
MPublicPar.RecordArg mRecordArg =new MPublicPar().new RecordArg(mContext);
Intent intent = new Intent(mContext,bll.RecordService.class);
intent.putExtra("resultCode",resultCode);
intent.putExtra("dataIntent",data);
intent.putExtra("mRecordArg",mRecordArg);
startService(intent);
方法1
public class RecordService extends Service {
private RecordHelper mRecordHelper;
private Context mContext;
@Override
public void onCreate(){
mContext=this;
mRecordHelper=new RecordHelper(mContext);
}
@Override
public void onDestroy(){
mRecordHelper.StopRecord();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
final int resultCode=intent.getIntExtra("resultCode",0);
final Intent mIntent=(Intent)intent.getParcelableExtra("dataIntent");
final MPublicPar.RecordArg mRecordArg=(MPublicPar.RecordArg)intent.getSerializableExtra("mRecordArg");
mRecordHelper.StartRecord(mRecordArg,resultCode,mIntent);
return super.onStartCommand(intent, flags, startId);
}
}
方法2
public class RecordService extends Service {
private RecordHelper mRecordHelper;
private Context mContext;
@Override
public void onCreate(){
mContext=this;
mRecordHelper=new RecordHelper(mContext);
}
@Override
public void onDestroy(){
mRecordHelper.StopRecord();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
final int resultCode=intent.getIntExtra("resultCode",0);
final Intent mIntent=(Intent)intent.getParcelableExtra("dataIntent");
final MPublicPar.RecordArg mRecordArg=(MPublicPar.RecordArg)intent.getSerializableExtra("mRecordArg");
new Thread(new Runnable() {
public void run() {
mRecordHelper.StartRecord(mRecordArg,resultCode,mIntent);
}
}).start();
return super.onStartCommand(intent, flags, startId);
}
}
RecordHelper.cs
public class RecordHelper {
private MediaRecorder mMediaRecorder;
private MediaProjection mMediaProjection;
private VirtualDisplay mVirtualDisplay;
private MediaProjectionManager mProjectionManager;
private Context mContext;
private Toast mToastText;
public RecordHelper(Context mContext){
this.mContext=mContext;
mProjectionManager = (MediaProjectionManager) mContext.getSystemService(Context.MEDIA_PROJECTION_SERVICE);
mMediaRecorder = new MediaRecorder();
}
public void StartRecord(RecordArg mRecordArg, int resultCode, Intent data){
initRecorder(mRecordArg);
prepareRecorder();
mMediaProjection = mProjectionManager.getMediaProjection(resultCode, data);
MediaProjectionCallback mMediaProjectionCallback = new MediaProjectionCallback();
mMediaProjection.registerCallback(mMediaProjectionCallback, null);
mVirtualDisplay=createVirtualDisplay(mRecordArg);
DelayStartRecord(mRecordArg);
}
public void StopRecord(){
try {
mMediaRecorder.stop();
mMediaRecorder.reset();
mVirtualDisplay.release();
mMediaRecorder.release();
mMediaProjection.stop();
mMediaProjection = null;
}catch (Exception e){
Utility.LogError("StopRecord Error " + e.getMessage() + " " + e.toString());
}
}
private void DelayStartRecord(RecordArg mRecordArg){
mMediaRecorder.start();
}
private void initRecorder(RecordArg mRecordArg) {
mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mMediaRecorder.setVideoEncodingBitRate(512 * 1000);
mMediaRecorder.setVideoFrameRate(30);
mMediaRecorder.setVideoSize(mRecordArg.screenWidth, mRecordArg.screenHeight);
mMediaRecorder.setOutputFile(mRecordArg.videoFilename);
}
private void prepareRecorder() {
try {
mMediaRecorder.prepare();
} catch (IllegalStateException e) {
e.printStackTrace();
Utility.LogError(e.getMessage());
} catch (IOException e) {
e.printStackTrace();
Utility.LogError(e.getMessage());
}
}
private VirtualDisplay createVirtualDisplay(RecordArg mRecordArg) {
return mMediaProjection.createVirtualDisplay("ScreenRecord",
mRecordArg.screenWidth, mRecordArg.screenHeight, mRecordArg.mScreenDensity,
DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
mMediaRecorder.getSurface(), null /*Callbacks*/, null /*Handler*/);
}
//Called when the MediaProjection session is no longer valid.
private class MediaProjectionCallback extends MediaProjection.Callback {
@Override
public void onStop() {
}
}
}
但我得到的错误java.lang.RuntimeException：不能创建处理程序内部线程没有调用Looper.prepare（），为什么？
我想你知道你的第二个问题。 事实上，如果你调用mRecordHelper.StartRecord(mRecordArg,resultCode,mIntent); 在主线程上，并不意味着所有代码函数都在该线程上运行，它所做的只是更新调用线程（这是主线程）上的UI信息，以及后台线程上的辛苦工作。 如果你从不同的线程中显式地调用，你正在指示它从那个线程中更改一个UI对象，因此你可以得到这个异常图片 - 一个使用异步任务的类，或者SurfaceView ，不会弄混先生，你可以随时查看源代码并看看它是如何工作的。
这不是什么大问题 - （我虚心地说）
为什么？ 这是否意味着MediaRecorder和MediaProjection函数在独立线程中工作？
检查以上 - 我猜是的
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