Android Studio Java-DecodeSampledBitmapFromResource不起作用

Question

I am new to android studio, I am trying to make an app that contains large number of images and of course I am getting the "OutOfMemory" error . I have searched for the solution and I found here a suggested method to solve it at this topic https://developer.android.com/topic/performance/graphics/load-bitmap.html

I have done the same method but after calling the decodeSampledBitmapFromResource, the image doesn't appear

here is the part of my code to call it

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    image = (ImageView) findViewById(R.id.step2pointaprob4exc2img);

    image.setImageBitmap(ImageNiver.decodeSampledBitmapFromResource(getResources(),R.id.step2pointaprob4exc2img,reqwidth1,reqheight1));

    Display display = getWindowManager().getDefaultDisplay();
    Point size = new Point();
    display.getSize(size);
    int reqwidth1 = size.x;
    int reqheight1 = size.y;


    String s = String.valueOf(reqwidth1);
    String ss = String.valueOf(reqheight1);
    Log.i("value of s :",s);
    Log.i("value of ss :",ss);

and here is the method i used at the class imageNiver

public class ImageNiver {
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;
        }

        // This offers some additional logic in case the image has a strange
        // aspect ratio. For example, a panorama may have a much larger
        // width than height. In these cases the total pixels might still
        // end up being too large to fit comfortably in memory, so we should
        // be more aggressive with sample down the image (=larger inSampleSize).

        long totalPixels = width * height / inSampleSize;

        // Anything more than 2x the requested pixels we'll sample down further
        final long totalReqPixelsCap = reqWidth * reqHeight * 2;

        while (totalPixels > totalReqPixelsCap) {
            inSampleSize *= 2;
            totalPixels /= 2;
        }

    }

    return inSampleSize;
}

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);
}

}

I have been searching for the solution for days but i couldn't find the answer to this problem.

Answer 1

In this line:

image.setImageBitmap(ImageNiver.decodeSampledBitmapFromResource(getResources(),R.id.step2pointaprob4exc2img,reqwidth1,reqheight1));

look twice at this R.id.step2pointaprob4exc2img

you should pass the id of the image in your resources (actual picture), not the id of the imageView like you are doing here.