从图库，Android，OpenCV显示图像

Question

I have a small android app to select image from gallery and show it in imageview. Now I want to do some processing on the image before showing it using OpenCV, but I can't get it show anything using OpenCV! Below is some relevant code:

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    try {
        // When an Image is picked
        if (requestCode == RESULT_LOAD_IMG && resultCode == RESULT_OK && null != data) {
            // Get the Image from data

            Uri selectedImage = data.getData();
            String[] filePathColumn = { MediaStore.Images.Media.DATA };

            // Get the cursor
            Cursor cursor = getContentResolver().query(selectedImage,
                    filePathColumn, null, null, null);
            // Move to first row
            cursor.moveToFirst();

            int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
            imgDecodableString = cursor.getString(columnIndex);
            cursor.close();

            File file = new File(imgDecodableString);
            Log.e(getString(R.string.app_name), "File exists: " + file.exists());
            Log.e(getString(R.string.app_name), "Trying to read: " + file.getAbsolutePath());
            image = Imgcodecs.imread(file.getAbsolutePath(),Imgcodecs.CV_LOAD_IMAGE_COLOR);
            ImageView imgView = (ImageView) findViewById(R.id.imgView);
            // Set the Image in ImageView after decoding the String
            float[] matrixValuesF = new float[image.cols()*image.rows()];
            double[] matrixValuesD = new double[matrixValuesF.length];
            image.get(0, 0, matrixValuesD);
            for (int i=0; i<matrixValuesD.length; i++) {
                matrixValuesF[i] = (float) matrixValuesD[i];
            }
            Matrix android_matrix = new Matrix();
            android_matrix.setValues(matrixValuesF);
            imgView.setImageMatrix(android_matrix);
            // imgView.setImageBitmap(BitmapFactory.decodeFile(imgDecodableString));


        } else {
            Toast.makeText(this, "You haven't picked Image",
                    Toast.LENGTH_LONG).show();
        }
    } catch (Exception e) {
        Toast.makeText(this, "Something went wrong", Toast.LENGTH_LONG)
                .show();
    }

}

Now the commented line at the end of if statement does work, but like I said I want to process the image before showing it.

Below is the logcat file:

E/MyApp: File exists: true
E/MyApp: Trying to read: /storage/emulated/0/images/img.jpg
D/OpenCV/StaticHelper: Trying to get library list
E/OpenCV/StaticHelper: OpenCV error: Cannot load info library for OpenCV
D/OpenCV/StaticHelper: Library list: ""
D/OpenCV/StaticHelper: First attempt to load libs
D/OpenCV/StaticHelper: Trying to init OpenCV libs
D/OpenCV/StaticHelper: Trying to load library opencv_java3
D/OpenCV/StaticHelper: Library opencv_java3 loaded
D/OpenCV/StaticHelper: First attempt to load libs is OK

When I run the app and select an image from the gallery I get a Toast message saying 'Something went wrong' and no image is displayed in the imageview.

I am new to android app development so I might be missing something simple. Thanks in advance.

Answer 1

Let me answer my own question. It seems that the method I was using for converting OpenCV mat to android Bitmap was wrong. The below code will do the job:

File file = new File(imgDecodableString);
Log.e(getString(R.string.app_name), "File exists: " + file.exists());
Log.e(getString(R.string.app_name), "Trying to read: " + file.getAbsolutePath());
image = Imgcodecs.imread(file.getAbsolutePath(),Imgcodecs.CV_LOAD_IMAGE_COLOR);
resultBitmap = Bitmap.createBitmap(image.cols(),  image.rows(),Bitmap.Config.ARGB_8888);;
Utils.matToBitmap(image, resultBitmap);
Bitmap mResult = resultBitmap;
ImageView imgView = (ImageView) findViewById(R.id.imgView);
imgView.setImageBitmap(mResult);