iOS Question this example take screenshot ..Any note?

Sub Button1_Click
    Dim noMe As NativeObject=Me
    Log("getScrhotImage")
    ' remove it
    ImageView1.Bitmap= noMe.runMethod("getScrhotImage",Null)

End Sub
#If OBJC

-(UIImage *)getScrhotImage
{

        CGRect scrRect = [[UIScreen mainScreen] bounds];
        UIGraphicsBeginImageContext(scrRect .size);
        CGContextRef ctx = UIGraphicsGetCurrentContext();
        [[UIColor blackColor] set];
        CGContextFillRect(ctx, scrRect );

          UIWindow *veiw= [UIApplication sharedApplication].keyWindow;

  
        [veiw.layer renderInContext:ctx];
        UIImage *image= UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
          UIGraphicsEndImageContext();

        return image;
}
#end if