getting images from external sd card folder and displaying them in a list

Question

Im trying to get images from a particular folder inside the external SD card and trying to show them inside a list when im running the app. No error provided, nothing happens. Just a blank page any suggestion.

i'm getting the list of images with the extension but how can i view the images!

 @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);


        File file = new File("/sdcard/external_sd/folder_name/");

        File imageList[] = file.listFiles();
        ArrayList<Bitmap> images = new ArrayList<Bitmap>();
        for(int i=0;i<imageList.length;i++)
        {
            Log.e("Image: "+i+": path", imageList[i].getAbsolutePath());

            Bitmap b = BitmapFactory.decodeFile(imageList[i].getAbsolutePath());

            images.add(b);

        }
         setListAdapter(new ArrayAdapter(this,
                android.R.layout.simple_list_item_1,imageList));
    }

Answer 1

You will face with OutOfMemory exception, if you use your code to load image. Try using the method below to load image correctly. After that you can populate your ListView.

private static final int IMG_BUFFER_LEN = 16384;
// R.drawable.ic_default - default drawable resource, if we cannot load drawable from provided file
// R.dimen.list_icon_size - size in dp of ImageView inside of ListView (for example, 40dp)

private Drawable extractMediaIcon(String filePath) {
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(filePath, options);
    if (options.outWidth < 0 || options.outHeight < 0 || (options.outWidth * options.outHeight == 0)) {
        return context.getResources().getDrawable(R.drawable.ic_default);
    }

    final int targetHeight = dp2px((int) context.getResources().getDimension(R.dimen.list_icon_size));
    final int targetWidth = targetHeight;

    final boolean isScaleByHeight =
        Math.abs(options.outHeight - targetHeight) >= Math.abs(options.outWidth - targetWidth);

    if (options.outHeight * options.outWidth * 2 >= IMG_BUFFER_LEN) {
        // Load, scaling to smallest power of 2 that'll get it <= desired dimensions
        final double sampleSize = isScaleByHeight
                ? options.outHeight / targetHeight
                : options.outWidth / targetWidth;
        options.inSampleSize =
                (int) Math.pow(2d, Math.floor(
                        Math.log(sampleSize) / Math.log(2d)));
    }

    // Do the actual decoding
    options.inJustDecodeBounds = false;
    options.inTempStorage = new byte[IMG_BUFFER_LEN];

    Bitmap bitmap = BitmapFactory.decodeFile(filePath, options);
    if (bitmap == null) {
        return context.getResources().getDrawable(R.drawable.ic_default);
    }

    final double imageFactor = (double) bitmap.getWidth() / bitmap.getHeight();
    final double targetFactor = (double) targetWidth / targetHeight;

    bitmap = Bitmap.createScaledBitmap(
            bitmap,
            targetFactor > imageFactor ? bitmap.getWidth() * targetHeight / bitmap.getHeight() : targetWidth,
            targetFactor > imageFactor ? targetHeight : bitmap.getHeight() * targetWidth / bitmap.getWidth(),
            false);

    return new BitmapDrawable(context.getResources(), bitmap);
}