The image uri didn't update after I first call the camera in my app

Question

When I want to get the image uri after I captured a photo, it always got nothing, but after I captured again, it returns the first one, not the current one. It seems like it always get the one before the latest. The following is my camerapreview code:

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
    private static final String TAG = "CameraPreview";
    private SurfaceHolder mHolder;
    private Camera mCamera;

    public static final int MEDIA_TYPE_IMAGE = 1;
    private Uri outputMediaFileUri;
    private String outputMediaFileType;
    public File pic;
    public Uri uri;


    public CameraPreview(Context context) {
        super(context);
        mHolder = getHolder();
        mHolder.addCallback(this);
    }

    private static Camera getCameraInstance() {
        Camera c = null;
        try {
            c = Camera.open();
        } catch (Exception e) {
            Log.d(TAG, "camera is not available");
        }
        return c;
    }

    public void surfaceCreated(SurfaceHolder holder) {
        mCamera = getCameraInstance();
        try {
            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();
        } catch (IOException e) {
            Log.d(TAG, "Error setting camera preview: " + e.getMessage());
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        mHolder.removeCallback(this);
        mCamera.setPreviewCallback(null);
        mCamera.stopPreview();
        mCamera.release();
        mCamera = null;
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        int rotation = getDisplayOrientation();
        mCamera.setDisplayOrientation(90);
    }




    private File getOutputMediaFile(int type) {
        File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES), TAG);
        if (!mediaStorageDir.exists()) {
            if (!mediaStorageDir.mkdirs()) {
                Log.d(TAG, "failed to create directory");
                return null;
            }
        }
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        File mediaFile;
        if (type == MEDIA_TYPE_IMAGE) {
            mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                    "prescription" + ".jpg");
            outputMediaFileType = "image/*";
        } else {
            return null;
        }
        outputMediaFileUri = Uri.fromFile(mediaFile);
        return mediaFile;
    }

    public Uri getOutputMediaFileUri() {
        return outputMediaFileUri;
    }

    public String getOutputMediaFileType() {
        return outputMediaFileType;
    }


    public void takePicture() {
        mCamera.takePicture(null, null, new Camera.PictureCallback() {
            @Override
            public void onPictureTaken(byte[] data, Camera camera) {
                File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
                Log.i("camera", "file done");
                if (pictureFile == null) {
                    Log.d(TAG, "Error creating media file, check storage permissions");
                    return;
                }
                try {
                    Log.i("camera", "do outputstream");
                    FileOutputStream fos = new FileOutputStream(pictureFile);
                    Log.i("camera", "after outputstream");
                    s = getOutputMediaFileUri().toString();
                    fos.write(data);
                    fos.close();



                } catch (FileNotFoundException e) {
                    Log.d(TAG, "File not found: " + e.getMessage());
                } catch (IOException e) {
                    Log.d(TAG, "Error accessing file: " + e.getMessage());
                }
            }
        });

    }



    public int getDisplayOrientation() {
        Display display = ((WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
        int rotation = display.getRotation();
        int degrees = 0;
        switch (rotation) {
            case Surface.ROTATION_0:
                degrees = 0;
                break;
            case Surface.ROTATION_90:
                degrees = 90;
                break;
            case Surface.ROTATION_180:
                degrees = 180;
                break;
            case Surface.ROTATION_270:
                degrees = 270;
                break;
        }

        android.hardware.Camera.CameraInfo camInfo =
                new android.hardware.Camera.CameraInfo();
        android.hardware.Camera.getCameraInfo(Camera.CameraInfo.CAMERA_FACING_BACK, camInfo);

        int result = (camInfo.orientation - degrees + 360) % 360;
        return result;
    }

}

After I call camerapreview.takepicture(), I tried to call camerapreview.outputMediaFileUri.toString(), but it doesn't work. Can someone help me?

Updated: I found that in the main activity, mPreview.takePicture() is always run at the end of all the precedures:

Button buttonCapturePhoto = (Button) findViewById(R.id.button_capture_photo);

        buttonCapturePhoto.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mPreview.takePicture();
                path = mPreview.geturi;
                goToFourthActivity(path);
             }
            }
        });

At each time, "path" will read the image uri FIRST, and then do mPreview.takePicture(). So it would always be the previous uri, I don't know why, how can I fix it?

Answer 1

Your code

mediaFile = new File(mediaStorageDir.getPath() + File.separator +
                "prescription" + ".jpg");

unconditionally reuses the same file name. No wonder you get the same URI.