与使用辅助类混淆

Question

I'm trying to use a Helper Class for having a little cleaner code. But I'm a little confused right now. let me first show you my codes:

this is my Helper Class Code (a code for scaling a bitmap):

public class Helper {
 public static void decodeFile(String filePath) {

    // Decode image size
    BitmapFactory.Options o = new BitmapFactory.Options();
    o.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(filePath, o);

    // The new size we want to scale to
    final int REQUIRED_SIZE = 2048;

    int width_tmp = o.outWidth, height_tmp = o.outHeight;
    int scale = 1;
    while (true) {
        if (width_tmp < REQUIRED_SIZE && height_tmp < REQUIRED_SIZE)
            break;
        width_tmp /= 2;
        height_tmp /= 2;
        scale *= 2;
    }

    BitmapFactory.Options o2 = new BitmapFactory.Options();
    o2.inSampleSize = scale;
    Bitmap bmp = BitmapFactory.decodeFile(filePath, o2);


}

and this is where I want to use the function:

public void onActivityResult(int requestCode, int resultCode, Intent data) {

    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == GALLERY_PICTURE) {
        if (resultCode == RESULT_OK) {


                Uri selectedImage = data.getData();
                String[] filePathColumn = {MediaStore.Images.Media.DATA};

                Cursor cursor = getContentResolver().query(selectedImage, filePathColumn, null, null, null);
                if (cursor != null) {
                cursor.moveToFirst();

                int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
                String filePath = cursor.getString(columnIndex);
                cursor.close();


               Helper.decodeFile(filePath);

               img_logo.setImageBitmap(bmp);

               settings = getSharedPreferences("pref", 0);
               Editor prefsEditor = settings.edit();
                    prefsEditor.putString("photo1", filePath);
                    prefsEditor.commit();
                }

but my problem is when It's going to display bitmap in my imageview(img_logo), it doesn't show the photo and just showes a blank page.

I know the problem is with last line of helper (where makes the bmp) but I don't know what to do.

Answer 1

You're not currently returning the bitmap which your helper class loads - you're creating it on this line:

Bitmap bmp = BitmapFactory.decodeFile(filePath, o2);

But then the function just exits, so the bitmap's forgotten. You need to return it to the function which calls it so it can then be displayed in the application:

bmp = Helper.decodeFile(filePath);

img_logo.setImageBitmap(bmp);