OutOfMemoryError android Bitmap listview

Question

In my application I use an SQLite database to store the data of a lot of images. Some images can be up to 600x600 pixels. I use a custom list to create the bitmaps. I know there is a method bitmap.recycle(); but I'm not sure how to use that with a listview.

possible duplicate of [Strange out of memory issue while loading an image to a Bitmap object](http://stackoverflow.com/questions/477572/strange-out-of-memory-issue-while-loading-an-image-to-a-bitmap-object) — tyczj, Jul 21 '14 at 17:34

score 0 · Accepted Answer · answered Jul 21 '14 at 17:34

Here is the solution to handle bitmaps in android

First, you should calculate the sampleBitmapSize of the bitmap ( to load the lower version of the same bitmap )

    public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId,
        int reqWidth, int reqHeight) {

    // First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeResource(res, resId, options);

    // Calculate inSampleSize
    options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;
    return BitmapFactory.decodeResource(res, resId, options);
}

Below is the util function to calculate InSampleSize ( an integer that defines the value (rating) of quality of a bitmap).

    public static int calculateInSampleSize(
        BitmapFactory.Options options, int reqWidth, int reqHeight) {
    // Raw height and width of image
    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;

    if (height > reqHeight || width > reqWidth) {

        final int halfHeight = height / 2;
        final int halfWidth = width / 2;

        // Calculate the largest inSampleSize value that is a power of 2 and keeps both
        // height and width larger than the requested height and width.
        while ((halfHeight / inSampleSize) > reqHeight
                && (halfWidth / inSampleSize) > reqWidth) {
            inSampleSize *= 2;
        }
    }

    Log.i("ImageUtil", "InSampleSize: "+inSampleSize);
    return inSampleSize;
}

using this technique i can handle 25kx25k pixel image easily on a non-ui thread. — Zeeshan Zulfiqar, Jul 21 '14 at 17:36
Thank you, and in the reqWidth and reqHeight parameters I should put the needed sizes such as 600x600? — Timothy Logan, Jul 21 '14 at 17:56
Yes, its the height and width of the bitmap that you want to have ( the smaller version of original bitmap). — Zeeshan Zulfiqar, Jul 21 '14 at 18:04
One more question, would I be able to resize the image back to a very large image without distorting it? — Timothy Logan, Jul 21 '14 at 18:15
You can create a byte array of the original image (see Bitmap to ByteArray Conversion). then you may pass to different functions ( make it constant to avoid any changes in data). — Zeeshan Zulfiqar, Jul 21 '14 at 18:19

OutOfMemoryError android Bitmap listview

1 Answers1