Question

The following code has a (at least one) deep flaw: Once CGFrame is set it’s location is fixed.

-(UIImageView*) ownImageView {

    if (ownImageView == nil) {
        ownImageView = [[UIImageView alloc] initWithFrame:
                  CGRectMake(self.xPosition, self.yPosition, 
                  [constants cardWidth], [constants cardHeight])];

        [ownImageView setImage:self.faceImage];
    }

    return ownImageView;
}

I would like to reuse the UIImageView (once created, I don’t want to realloc it). Instead, i’d like to change x,y coordinates of the frame it contains.

The following code works fine, however, it seems carelessly wasteful

-(UIImageView*) ownImageView {

    [ownImageView removeFromSuperview];
    ownImageView = [[UIImageView alloc] initWithFrame:
               CGRectMake(self.xPosition, self.yPosition, 
               [constants cardWidth], [constants cardHeight])];

    [ownImageView setImage:self.faceImage];

    return ownImageView;
}

Question: How would you handle this, while keeping as much of lazy instantiation as possible?

The view represents a 2d rectangle moving along the screen. I’d like to represent the “move” by simply changing X/Y position of the existing view instead of replacing it with a new copy.

Answer 1

ownImageView.frame = CGRectMake(x,y,w,h);