Android: BitmapFactory.decodeStream() out of memory with a 400KB file with 2MB free heap

Question

My app is hitting an OOM error at the following line in the source: ``` image = BitmapFactory.decodeStream(assetManager.open(imgFilename)); ``` Just before the allocation that causes the app to be killed with an OOM error: ``` (...) 08-05 21:22:12.443: I/dalvikvm-heap(2319): Clamp target GC heap from 25.056MB to 24.000MB 08-05 21:22:12.443: D/dalvikvm(2319): GC_FOR_MALLOC freed <1K, 50% free 2709K/5379K, external 18296K/19336K, paused 58ms 08-05 21:22:14.513: D/dalvikvm(2319): GC_EXTERNAL_ALLOC freed <1K, 50% free 2709K/5379K, external 18296K/19336K, paused 101ms 08-05 21:22:14.903: I/dalvikvm-heap(2319): Clamp target GC heap from 25.073MB to 24.000MB 08-05 21:22:14.903: D/dalvikvm(2319): GC_FOR_MALLOC freed 0K, 50% free 2709K/5379K, external 18312K/19336K, paused 53ms 08-05 21:22:22.843: D/ddm-heap(2319): Heap GC request 08-05 21:22:22.963: I/dalvikvm-heap(2319): Clamp target GC heap from 25.073MB to 24.000MB 08-05 21:22:22.963: D/dalvikvm(2319): threadid=1: still suspended after und…

Accepted Answer

Android library is not so smart for loading images, so you have to create workarounds for this.

In my tests, `Drawable.createFromStream` uses more memory than `BitmapFactory.decodeStream`.

You may change the Color scheme to reduce memory (RGB_565), but the image will lose quality too:

```
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Config.RGB_565;
Bitmap bitmap = BitmapFactory.decodeStream(stream, null, options);
```

Reference: http://developer.android.com/reference/android/graphics/Bitmap.Config.html

You can also load a scaled image, which will decrease a lot the memory usage, but you have to know your images to not lose too much quality of it.

```
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 2;
Bitmap bitmap = BitmapFactory.decodeStream(stream, null, options);
```

Reference: http://developer.android.com/reference/android/graphics/BitmapFactory.Options.html

To define the inSampleSize dynamically, you may want to know the image size to take your decision:

```
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
bitmap = BitmapFactory.decodeStream(stream, null, options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;

options.inJustDecodeBounds = false;
// recreate the stream
// make some calculation to define inSampleSize
options.inSampleSize = ?;
Bitmap bitmap = BitmapFactory.decodeStream(stream, null, options);
```

You can customize the inSampleSize according to the screen size of the device. To get the screen size, you can do:

```
DisplayMetrics metrics = new DisplayMetrics();
((Activity) activity).getWindowManager().getDefaultDisplay().getMetrics(metrics);
int screenWidth = metrics.widthPixels;
int screenHeight = metrics.heightPixels;
```

Android: BitmapFactory.decodeStream() out of memory with a 400KB file with 2MB free heap

Solution

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