android - 在表面 View 中授予权限后相机未打开

Question

我正在制作自定义相机应用程序。这需要表面 View 并在表面 View 内打开相机。但是当我在 marshmallow 上运行相同的应用程序时，我正在使用 Runtime permission 来授予相机权限。在我允许对话框消失但出现黑屏并且相机无法打开后。我也尝试过在允许后再次调用该 Activity ，但它不起作用。

提前致谢。

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
    if (preview) {
        camera.stopFaceDetection();
        camera.stopPreview();
        preview = false;
    }

    if (camera != null) {
        preview = true;
        // Parameters
        Parameters parameters = camera.getParameters();
        parameters.setFocusMode(Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
        List<Camera.Size> sizeList = camera.getParameters().getSupportedPreviewSizes();
        bestSize = sizeList.get(0);
        for (int i = 1; i < sizeList.size(); i++) {
            if ((sizeList.get(i).width * sizeList.get(i).height) >
                    (bestSize.width * bestSize.height)) {
                bestSize = sizeList.get(i);
            }
        }
        parameters.setPictureSize(bestSize.width, bestSize.height);
        camera.setParameters(parameters);
        camera.startPreview();
        camera.startFaceDetection();
        camera.setFaceDetectionListener(faceDetectionListener);
    }
}
@Override
public void surfaceCreated(SurfaceHolder holder) {

    customsurfaceview();
}
public void customsurfaceview() {

    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
        Log.e("PLAYGROUND", "Permission is not granted, requesting");
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, 123);
    }
    Log.e("Entered Surace Created", "----------------");
}
public void SetPreview_onSurface() {
    if (camera == null)
        return;


    camera = Camera.open();
    try {
        camera.setPreviewDisplay(surfaceView.getHolder());
    } catch (IOException e) {
        e.printStackTrace();
        Log.e("printStackTrace", "--" + e.getMessage());

    }
    camera_button = (ImageView) findViewById(R.id.camera_button);
    camera_button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (capture_chek == 0) {
                camera.cancelAutoFocus();
                camera.takePicture(shutterCallback, null, pictureCallback);
                capture_chek = 1;
            }
        }
    });
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    if (camera != null) {
        camera.release();
        camera = null;
        preview = false;
    }
}

Answer 1

这个问题可能太老了，但可以帮助其他遇到与我相同问题的人。我的修复是...

在 OnCreate() 中，我删除了 setContentView(R.layout...) 然后我将仅在 OnCreate() 和 onRequestPermissionsResult() 中调用 initializeUiAndCamera()(如果已授予权限)。

在 initializeUiAndCamera() 内部，我在这里调用了 setContentView(R.layout...) 并膨胀了我需要的所有 View 。

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    if (ContextCompat.checkSelfPermission(this,
            Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
        ActivityCompat.requestPermissions(this,
            arrayOf(Manifest.permission.CAMERA), REQUEST_CAMERA)
    else
        initializeUiAndCamera()
}

private fun initializeUiAndCamera() {
    setContentView(R.layout.activity_qr_scanner)

    surfaceView = findViewById(R.id.surfaceView)

    //...
}

override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>, grantResults: IntArray) {
    when (requestCode) {
        REQUEST_CAMERA -> {
            if (grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) 
                initializeUiAndCamera()
            else 
                Toast.makeText(applicationContext, "Camera Permission denied", Toast.LENGTH_SHORT).show()

        }
    }
}

TLDR；仅在授予权限时扩充您的 View 。