android - 在我允许后表面 View 不显示相机

Question

public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_camera, container, false);
    cameraId = Camera.CameraInfo.CAMERA_FACING_BACK;
    flipCamera = view.findViewById(R.id.flipCamera);
    flashCameraButton = view.findViewById(R.id.flash);
    captureImage = view.findViewById(R.id.captureImage);
    surfaceView = view.findViewById(R.id.surfaceView);
    surfaceHolder = surfaceView.getHolder();
    surfaceHolder.addCallback(this);
    flipCamera.setOnClickListener(this);
    captureImage.setOnClickListener(this);
    flashCameraButton.setOnClickListener(this);
    getActivity().getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

    if (Camera.getNumberOfCameras() > 1) {
        flipCamera.setVisibility(View.VISIBLE);
    }
    if (!getActivity().getBaseContext().getPackageManager().hasSystemFeature(
            PackageManager.FEATURE_CAMERA_FLASH)) {
        flashCameraButton.setVisibility(View.GONE);
    }


    return view;
}

@RequiresApi(api = Build.VERSION_CODES.M)
@Override
public void surfaceCreated(SurfaceHolder holder) {

    if (!openCamera(Camera.CameraInfo.CAMERA_FACING_BACK)) {
        alertCameraDialog();
    }

}


private boolean openCamera(int id) {
    boolean result = false;
    cameraId = id;
    releaseCamera();
    try {
        camera = Camera.open(cameraId);
    } catch (Exception e) {
        e.printStackTrace();
    }
    if (camera != null) {
        try {
            setUpCamera(camera);
            camera.setErrorCallback(new Camera.ErrorCallback() {

                @Override
                public void onError(int error, Camera camera) {

                }
            });
            camera.setPreviewDisplay(surfaceHolder);
            camera.startPreview();
            result = true;
        } catch (IOException e) {
            e.printStackTrace();
            result = false;
            releaseCamera();
        }
    }
    return result;
}

private void setUpCamera(Camera c) {
    Camera.CameraInfo info = new Camera.CameraInfo();
    Camera.getCameraInfo(cameraId, info);
    rotation = getActivity().getWindowManager().getDefaultDisplay().getRotation();
    int degree = 0;
    switch (rotation) {
        case Surface.ROTATION_0:
            degree = 0;
            break;
        case Surface.ROTATION_90:
            degree = 90;
            break;
        case Surface.ROTATION_180:
            degree = 180;
            break;
        case Surface.ROTATION_270:
            degree = 270;
            break;

        default:
            break;
    }

    if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
        // frontFacing
        rotation = (info.orientation + degree) % 330;
        rotation = (360 - rotation) % 360;
    } else {
        // Back-facing
        rotation = (info.orientation - degree + 360) % 360;
    }
    c.setDisplayOrientation(rotation);
    Camera.Parameters params = c.getParameters();

    showFlashButton(params);

    List<String> focusModes = params.getSupportedFlashModes();
    if (focusModes != null) {
        if (focusModes
                .contains(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE)) {
            params.setFlashMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
        }
    }

    params.setRotation(rotation);
}

private void showFlashButton(Camera.Parameters params) {
    boolean showFlash = (getActivity().getPackageManager().hasSystemFeature(
            PackageManager.FEATURE_CAMERA_FLASH) && params.getFlashMode() != null)
            && params.getSupportedFlashModes() != null
            && params.getSupportedFocusModes().size() > 1;

    flashCameraButton.setVisibility(showFlash ? View.VISIBLE
            : View.INVISIBLE);

}

private void releaseCamera() {
    try {
        if (camera != null) {
            camera.setPreviewCallback(null);
            camera.setErrorCallback(null);
            camera.stopPreview();
            camera.release();
            camera = null;
        }
    } catch (Exception e) {
        e.printStackTrace();
        Log.e("error", e.toString());
        camera = null;
    }
}

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

}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {

}

@Override
public void onClick(View v) {
    switch (v.getId()) {
        case R.id.flash:
            flashOnButton();
            break;
        case R.id.flipCamera:
            flipCamera();
            break;
        case R.id.captureImage:
            takeImage();
            break;

        default:
            break;
    }
}

private void takeImage() {
    camera.takePicture(null, null, new Camera.PictureCallback() {

        private File imageFile;

        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            try {
                // convert byte array into bitmap
                Bitmap loadedImage = null;
                Bitmap rotatedBitmap = null;
                loadedImage = BitmapFactory.decodeByteArray(data, 0, data.length);

                // rotate Image
                Matrix rotateMatrix = new Matrix();
                rotateMatrix.postRotate(rotation);
                rotatedBitmap = Bitmap.createBitmap(loadedImage, 0, 0,
                        loadedImage.getWidth(), loadedImage.getHeight(),
                        rotateMatrix, false);
                String state = Environment.getExternalStorageState();
                File folder = null;
                if (state.contains(Environment.MEDIA_MOUNTED)) {
                    folder = new File(Environment
                            .getExternalStorageDirectory() + "/Demo");
                } else {
                    folder = new File(Environment
                            .getExternalStorageDirectory() + "/Demo");
                }

                boolean success = true;
                if (!folder.exists()) {
                    success = folder.mkdirs();
                }
                if (success) {
                    java.util.Date date = new java.util.Date();
                    imageFile = new File(folder.getAbsolutePath()
                            + File.separator
                            + new Timestamp(date.getTime()).toString()
                            + "Image.jpg");

                    imageFile.createNewFile();
                    Toast.makeText(getActivity().getBaseContext(), "Image Saved", Toast.LENGTH_SHORT).show();
                    openCamera(cameraId);
                } else {
                    Toast.makeText(getActivity().getBaseContext(), "Image Not saved", Toast.LENGTH_SHORT).show();
                    return;
                }

                ByteArrayOutputStream ostream = new ByteArrayOutputStream();

                // save image into gallery
                rotatedBitmap.compress(Bitmap.CompressFormat.JPEG, 100, ostream);

                FileOutputStream fout = new FileOutputStream(imageFile);
                fout.write(ostream.toByteArray());
                fout.close();
                ContentValues values = new ContentValues();

                values.put(MediaStore.Images.Media.DATE_TAKEN, System.currentTimeMillis());
                values.put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg");
                values.put(MediaStore.MediaColumns.DATA, imageFile.getAbsolutePath());
                getActivity().getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);

            } catch (Exception e) {
                e.printStackTrace();
            }

        }
    });

}


private void flipCamera() {
    int id = (cameraId == Camera.CameraInfo.CAMERA_FACING_BACK ? Camera.CameraInfo.CAMERA_FACING_FRONT
            : Camera.CameraInfo.CAMERA_FACING_BACK);
    if (!openCamera(id)) {
        alertCameraDialog();
    }
}

private void alertCameraDialog() {
    Toast.makeText(getActivity(), "Error to open camera", Toast.LENGTH_SHORT).show();
}


private void flashOnButton() {
    if (camera != null) {
        try {
            Camera.Parameters param = camera.getParameters();
            param.setFlashMode(!flashmode ? Camera.Parameters.FLASH_MODE_TORCH
                    : Camera.Parameters.FLASH_MODE_OFF);
            camera.setParameters(param);
            flashmode = !flashmode;
        } catch (Exception e) {
            // TODO: handle exception
        }

    }
}

这是我的相机 fragment 代码。当我在运行时授予权限时，surfaceview 不显示相机。它在 onResume() 或点击该 fragment 中的任何按钮时显示相机。如何解决这个问题。如何设置当我在许可中单击“允许”按钮时，它会自动在表面 View 中显示相机。

Answer 1

在 onCreate 中将 surfaceView 的可见性设置为 INVISIBLE。

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home);

    if (checkCameraHardware(this) == false) {
        showDialogForExit();
    }
    surfaceView = (SurfaceView) findViewById(R.id.surfaceView);
    surfaceView.setVisibility(View.INVISIBLE);
    infoTextview = (TextView) findViewById(R.id.info_text);
    askForPermissions();
}

然后在将cameraSource附加到surfaceView之后，再次将surfaceView的可见性设置为VISIBLE。

        surfaceView.setVisibility(View.VISIBLE);