从内部存储读取时，BitmapFactory.decodeStream返回null

Question

I attempt to read images from the internal storage, when I decode FileInputStream, BufferedInputStream or a File using BitmapFactory I get null as a result:

//mImages is an ArrayList of image file names, "a.jpg","b.jpg", etc.
//This is inside my custom adapter for returing ImageViews from mImages:

public View getView(int position, View ..., ViewGroup...){
Context base_context = MyApplication.getAppContext();

String currentImageFilename = mImages.get(position); //say this is "cat.jpg"

//after this line f = "/data/user/0/mobile.foo.bar/files/cat.jpg"
File f = base_context.getFileStreamPath(currentImageFilename);

Boolean ex = f.exists(); //returns true, inserted only for debugging as no 
//exception was thrown when decoding the bitmap and the result is null

BufferedInputStream buffer = new BufferedInputStream(new FileInputStream(f));

Bitmap img = BitmapFactory.decodeStream(buffer); // img is null after this line
imageView.setImageBitmap(img);
}

I tried all other answers I could find, but no luck so far.

Answer 1

If you're running this code on Android 7 and you use BitmapFactory.decodeStream you need to reset InputStream every time you want yo use it again. For example I used it twice, first to get some metrics and then to decode into Bitmap. And it worked fine on all versions prior to Android 7.

Now I need to reset it, otherwise it returns null :

BitmapFactory.decodeStream(iStream, null, options);
...
try {
    iStream.reset();
} catch (IOException e) {
    return null;
}
...
BitmapFactory.decodeStream(iStream, null, options);

Resetting inputStream won't cause any bugs on older versions so it's safe to use.

If it helped in your case - all credits to this guy: https://stackoverflow.com/a/41753686/5502121