Display big image from SD card in Android

Question

In Android, how do you display an image (of any size) from the SD card, without getting an out of memory error?

Is it necessary to put the image in the Media Store first?

A pseudo-code example would be greatly appreciated. Extra points if the displayed image is as big as the memory level of the device allows.

Answer 1

Edit: this question has actually been already answered at Strange out of memory issue while loading an image to a Bitmap object (the two highest voted answers). It does also use the inSampleSize option, but with a small method to automatically get the appropriate value.

My original answer:

The inSampleSize of the BitmapFactory.Options class can solve your issue (http://developer.android.com/reference/android/graphics/BitmapFactory.Options.html#inSampleSize). It works by making a bitmap with the resulting width and height 1/inSampleSize than the original, thus reducing memory consumption (by inSampleSize^2?). You should read the doc before using it.

Example:

BitmapFactory.Options options = new BitmapFactory.Options();
// will results in a much smaller image than the original
options.inSampleSize = 8;

// don't ever use a path to /sdcard like this, but I'm sure you have a sane way to do that
// in this case nebulae.jpg is a 19MB 8000x3874px image
final Bitmap b = BitmapFactory.decodeFile("/sdcard/nebulae.jpg", options);

final ImageView iv = (ImageView)findViewById(R.id.image_id);
iv.setImageBitmap(b);
Log.d("ExampleImage", "decoded bitmap dimensions:" + b.getWidth() + "x" + b.getHeight()); // 1000x485

However here it will only work for images up to, I guess, inSampleSize^2 times the size of the allowed memory and will reduce the quality of small images. The trick would be to find the appropriate inSampleSize.