In android 6.0.1, why got null when trying getting Bitmap from Uri after taking photo via camera?

Question

This problem occurs in android 6.0.1, but not in android 7.0. I have this class FileKit to take photo via camera and it has method uriToBitmap() which turns Uri into Bitmap. taken_photo_uri stores the taken photo's uri.

class FileKit{
  public static Uri taken_photo_uri = null;

  public static void takePhoto(RootActivity activity) {
        open_camera_activity = activity;
        if (ContextCompat.checkSelfPermission(MyApplicaiton.getContext(),
                Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {

            activity.setPermissionRequestInterface(getContext());
            ActivityCompat.requestPermissions(activity,
                    new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, REQ_READ_PHOTO);

        } else {
            File output_image = new File(MyApplicaiton.getContext().getExternalCacheDir(), "output_image.jpg");
            try {
                if (output_image.exists()) {
                    output_image.delete();
                }
                output_image.createNewFile();
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (Build.VERSION.SDK_INT >= 24) {
                taken_photo_uri = FileProvider.getUriForFile(MyApplicaiton.getContext(),
                        activity.getResources().getString(R.string.main_package),
                        output_image);
            } else {
                taken_photo_uri = Uri.fromFile(output_image);
            }

            Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
            intent.putExtra(MediaStore.EXTRA_OUTPUT, taken_photo_uri);
            activity.startActivityForResult(intent, TAKE_PHOTO);
        }
    }

    public static Bitmap uriToBitmap(Uri uri) {
        Bitmap bitmap = null;

        try {
            bitmap = BitmapFactory.decodeStream(MyApplicaiton.getContext().getContentResolver().openInputStream(uri));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        return bitmap;
    }

Here's how I use it in a demo Activity:

button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                FileKit.takePhoto(activity);
            }
        });

 @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        switch (requestCode) {
            case FileKit.TAKE_PHOTO:
                if (resultCode == RESULT_OK) {
                    Bitmap bitmap = FileKit.uriToBitmap(FileKit.taken_photo_uri);
                    if (bitmap == null) {
                        GeneralUtil.showToast("null picture");
                    } else {
                        GeneralUtil.showToast("not null picture");
                        imageView.setImageBitmap(bitmap);
                    }
                }
                break;
        }
    }

Things are good in android 7.0 but uriToBitmap(Uri uri) returns null in android 6.0.1. How to fix it? Thanks!

Answer 1

Take a look in

takePhoto(){
 if (Build.VERSION.SDK_INT >= 24) {
                taken_photo_uri = FileProvider.getUriForFile(MyApplicaiton.getContext(),
                        activity.getResources().getString(R.string.main_package),
                        output_image);
            } else {
                taken_photo_uri = Uri.fromFile(output_image);
            }
}

Your version check calls FileProvider.getUriForFile() on Nougat and above. From android docs ( https://developer.android.com/reference/android/os/Build.VERSION_CODES ), getUriForFile() returns a Uri as expected. However, on Marshmallow and below, you make a call to Uri.fromFile() which, again according to android docs ( https://developer.android.com/reference/android/net/Uri.html#fromFile(java.io.File) ) returns a Uri prefixed with "file://."

Without knowing much about Uri or Android specifically, I'd say that might be the issue.