Question

听是我的片段代码。我正在使用媒体播放器进行录制当我仅使用像ForntCamera和BackCamera这样的单个摄像头时，此代码有效，但是当我使用camaraId切换摄像头时，媒体播放器会给出“无效的预览图面”异常。我哪里错了？请帮我。谢谢，谢谢

import android.hardware.Camera;
import android.media.CamcorderProfile;
import android.media.MediaPlayer;
import android.media.MediaRecorder;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.TextClock;

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;



import static android.provider.MediaStore.Files.FileColumns.MEDIA_TYPE_IMAGE;   
import static android.provider.MediaStore.Files.FileColumns.MEDIA_TYPE_VIDEO;  
import static mms.dweb.buzzcutz.ApplicationContext.TAG;

public class VideoRecordFragmentB extends BaseFragment {


@BindView(R.id.record_btn_frb)
ImageView record_btn;
@BindView(R.id.cameraSwitch)
ImageView cameraSwitch;
@BindView(R.id.mTextField)
TextClock mTextField;
int camId = 0;
@BindView(R.id.camera_preview)
FrameLayout preview;
MediaPlayer mediaPlayer;
String catId;
Boolean back = true;
private View fragmentView;
private MainActivity mainActivity;
private Camera mCamera;
private CameraPreview mPreview;
private MediaRecorder mMediaRecorder;
private boolean isRecording = false;
private CategoryResponce.Responsedata categoryData;

private static Uri getOutputMediaFileUri(int type) {
    return Uri.fromFile(getOutputMediaFile(type));
}

/**
 * Create a File for saving an image or video
 */
private static File getOutputMediaFile(int type) {
    // To be safe, you should check that the SDCard is mounted
    // using Environment.getExternalStorageState() before doing this.

    File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES), "Buzzcut");
    // This location works best if you want the created images to be shared
    // between applications and persist after your app has been uninstalled.

    // Create the storage directory if it does not exist
    if (!mediaStorageDir.exists()) {
        if (!mediaStorageDir.mkdirs()) {
            Log.d("MyCameraApp", "failed to create directory");
            return null;
        }
    }

    // Create a media file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    File mediaFile;
    if (type == MEDIA_TYPE_IMAGE) {
        mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                "IMG_" + timeStamp + ".jpg");
    } else if (type == MEDIA_TYPE_VIDEO) {
        mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                "VID_" + timeStamp + ".mp4");
    } else {
        return null;
    }

    return mediaFile;
}

@OnClick(R.id.cameraSwitch)
void changeCam() {
    if (camId == 0) {
        camId = 1;
    } else {
        camId = 0;
    }
    managView();
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    fragmentView = 
   inflater.inflate(R.layout.fragment_video_record_fragment_b, container, false);
    ButterKnife.bind(this, fragmentView);
    initializeView();
    return fragmentView;

}

@Override
public void initializeView() {
    super.initializeView();
    if (getActivity() instanceof MainActivity) {
        mainActivity = (MainActivity) getActivity();
    }

    managView();
}

private void managView() {
    mCamera = getCameraInstance(camId);
    mPreview = new CameraPreview(getContext(), mCamera);
    preview.addView(mPreview);
    Bundle bundle = getArguments();
    categoryData = (CategoryResponce.Responsedata) 
    bundle.getSerializable("CategoryResponceData");
    catId = categoryData.getId();
    Bundle bundle1 = new Bundle();
    bundle1.putSerializable("CategoryResponceData", categoryData);


    record_btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (isRecording) {
                // stop recording and release camera
                mMediaRecorder.stop();  // stop the recording
                releaseMediaRecorder(); // release the MediaRecorder object
                mCamera.lock();// take camera access back from MediaRecorder
                record_btn.setImageResource(R.drawable.record_btn);
                // inform the user that recording has stopped
                isRecording = false;
                Bundle bundle = new Bundle();
                bundle.putString("fileUri", 
     getOutputMediaFileUri(MEDIA_TYPE_VIDEO).toString());
                bundle.putSerializable("CategoryResponceData", categoryData);

mainActivity.replaceFragment(FragmentNames.VideoUploadFragment, bundle, false, false);
            } else {
                // initialize video camera
                if (prepareVideoRecorder(camId)) {
                    // Camera is available and unlocked, MediaRecorder is prepared,
                    // now you can start recording
                    record_btn.setImageResource(R.drawable.recoder);
                    mMediaRecorder.start();
                    // inform the user that recording has started
                    isRecording = true;
                } else {
                    // prepare didn't work, release the camera
                    releaseMediaRecorder();
                    // inform user
                }
            }
        }
    });

}

@Override
public void onStop() {
    super.onStop();
}

public Camera getCameraInstance(int camid) {
    releaseCameraAndPreview();
    Camera c = null;
    try {
        c = Camera.open(camid); // attempt to get a Camera instance
    } catch (Exception e) {
        // Camera is not available (in use or does not exist)
    }
    return c; // returns null if camera is unavailable
}

private void releaseCameraAndPreview() {
    preview.removeAllViews();
    if (mCamera != null) {
        mCamera.release();
        mCamera = null;
    }
}

private boolean prepareVideoRecorder(int camid) {
    mCamera = getCameraInstance(camid);
    mMediaRecorder = new MediaRecorder();


    mCamera.unlock();
    mMediaRecorder.setCamera(mCamera);


    mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
    mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);


    mMediaRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH));


    mMediaRecorder.setOutputFile(getOutputMediaFile(MEDIA_TYPE_VIDEO).toString());


    mMediaRecorder.setPreviewDisplay(mPreview.getHolder().getSurface());


    try {
        mMediaRecorder.prepare();
    } catch (IllegalStateException e) {
        Log.d(TAG, "IllegalStateException preparing MediaRecorder: " + e.getMessage());
        releaseMediaRecorder();
        return false;
    } catch (IOException e) {
        Log.d(TAG, "IOException preparing MediaRecorder: " + e.getMessage());
        releaseMediaRecorder();
        return false;
    }
    return true;
}

@Override
public void onPause() {
    super.onPause();
    releaseMediaRecorder();       // if you are using MediaRecorder, release it first
    releaseCamera();              // release the camera immediately on pause event
}

private void releaseMediaRecorder() {
    if (mMediaRecorder != null) {
        mMediaRecorder.reset();   // clear recorder configuration
        mMediaRecorder.release(); // release the recorder object
        mMediaRecorder = null;
        mCamera.lock();           // lock camera for later use
    }
}

private void releaseCamera() {
    if (mCamera != null) {
        mCamera.release();        // release the camera for other applications
        mCamera = null;
    }
}
}

听力是“相机预览类”。我正在使用此类来获取相机

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private SurfaceHolder mHolder;
private Camera mCamera;
private CamcorderProfile camcorderProfile;

public CameraPreview(Context context, Camera camera) {
    super(context);
    mCamera = camera;


    mHolder = getHolder();
    mHolder.addCallback(this);

    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}

public void surfaceCreated(SurfaceHolder holder) {
   preview.
    try {
        mCamera.setPreviewDisplay(holder);
        mCamera.setDisplayOrientation(90);

        mCamera.startPreview();
    } catch (IOException e) {
        Log.d(TAG, "Error setting camera preview: " + e.getMessage());
    }
}

public void surfaceDestroyed(SurfaceHolder holder) {

}

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {

    if (mHolder.getSurface() == null){

        return;
    }


    try {
        mCamera.stopPreview();
    } catch (Exception e){

    }


    try {
        mCamera.setPreviewDisplay(mHolder);
        mCamera.setDisplayOrientation(90);
        mCamera.startPreview();

    } catch (Exception e){
        Log.d(TAG, "Error starting camera preview: " + e.getMessage());
    }
}
}

Answer 1

无论如何，请在onResume中初始化视图

@Override
public void onResume() {
     super.onResume();
     initializeView();
}

您是否已在清单中声明了许可？

<uses-permission android:name="android.permission.RECORD_AUDIO" />

当Media Player准备并且Media Player未在Android中录制时，预览表面无效

1 个答案: