How to open the default gallery from android and receive the picked uri of the picture?

Use below code to create and fire a intent to start Gallery

Intent pickPhoto = new Intent(Intent.ACTION_PICK,
                                       android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                            startActivityForResult(pickPhoto , 0);

and below line in onActivityResult(int requestCode, int resultCode, Intent data) method to fetch URI

Uri dataUri = data.getData(); //Image URI

You would most probably need below method to convert this Image URI to small size bitmap . if showing image in your display, as without it , it could result in OOM exception

private Bitmap decodeUri(Uri selectedImage) throws FileNotFoundException {

    // Decode image size
    BitmapFactory.Options o = new BitmapFactory.Options();
    o.inJustDecodeBounds = true;
    BitmapFactory.decodeStream(getContentResolver().openInputStream(selectedImage), null, o);

    // The new size we want to scale to
    final int REQUIRED_SIZE = 140;

    // Find the correct scale value. It should be the power of 2.
    int width_tmp = o.outWidth, height_tmp = o.outHeight;
    int scale = 1;
    while (true) {
        if (width_tmp / 2 < REQUIRED_SIZE
           || height_tmp / 2 < REQUIRED_SIZE) {
            break;
        }
        width_tmp /= 2;
        height_tmp /= 2;
        scale *= 2;
    }

    // Decode with inSampleSize
    BitmapFactory.Options o2 = new BitmapFactory.Options();
    o2.inSampleSize = scale;
    return BitmapFactory.decodeStream(getContentResolver().openInputStream(selectedImage), null, o2);

}