如何使ImageView变为屏幕分辨率的两倍

Question

I am trying to set the height and width of an imageview to be twice the size of the height and width of the screen, which obviously changes depending on what device is used. This is what I attempted (but the imageview was just invisible):

public class MainActivity extends AppCompatActivity {
private ImageView Geoline;

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

//Fetching the Device Resolution
    Display display = getWindowManager().getDefaultDisplay();
    Point size = new Point();
    display.getSize(size);
    int scrWidth = size.x;
    int scrHeight = size.y;

 //Creating variables that are twice the size of screen resolutions
    int scalex = 2 * scrWidth;
    int scaley = 2 * scrHeight;


 //Setting the screen width and height to equal that of variables "scalex" and "scaley"
    Geoline.setScaleX(scalex);
    Geoline.setScaleY(scaley);
}

Answer 1

You are trying to do this in onCreate() where View is not yet rendered, trying moving your code to onResume() or even better do like this

mBinding.parentView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {

            }
        });

Move your code inside this, it will work.