Android: Rotate and display image from file

Question

I have a very simple layout with an ImageView. My application opens the camera, saves an image, and then displays the image in the ImageView with BitmapFactory.decodeFile. The only issue is that it's rotated. I understand that a) this is due to the phone's camera defaulting to landscape, so this needs to be handled in code and b) image processing must be done in a separate thread from the UI.

The Android training documentation seems to be geared toward loading images from resource id's instead of file paths. This just throws a wrench in things as I'm able to follow the tutorials up to a point but ultimately have trouble reconciling the differences.

I'm certainly new at this so if someone could just give me a high-level overview of what needs to be done to accomplish this, I'd really appreciate it. The following code is where I'm currently adding the bitmap to the ImageView. I assume that my call to the separate thread would go in onCreate?

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

    Bitmap bm = BitmapFactory.decodeFile(MainActivity.image_path);

    displayImageView = (ImageView) findViewById(R.id.myImageView);

    displayImageView.setImageBitmap(bm);
}

Answer 1

Use ExifInterface for rotate

picturePath = getIntent().getStringExtra("path");
Bitmap bitmap = BitmapFactory.decodeFile(picturePath);
ExifInterface exif = new ExifInterface(picturePath);
int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_UNDEFINED);

Matrix matrix = new Matrix();
switch (orientation) {
case ExifInterface.ORIENTATION_ROTATE_90:
    matrix.postRotate(90);
    break;
case ExifInterface.ORIENTATION_ROTATE_180:
    matrix.postRotate(180);
    break;
case ExifInterface.ORIENTATION_ROTATE_270:
    matrix.postRotate(270);
    break;
default:
    break;
}

myImageView.setImageBitmap(bitmap);
bitmap.recycle();

Note : Here picturePath is selected Image's path from Gallery

• tutorial