Question

I was wondering what was the real meaning of using initWithFrame with this scrollView, because we also set the dimensions of the scrollView after that, and we add the scrollView as a subView of the view.

So why do we need to specify this initWithFrame? I actually don’t really understand it when the frame is self.view.frame (I would understand it better if we set a different rectangle, such as 0,0 50,50)

UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:self.view.frame];

scrollView.contentSize = CGSizeMake(847, 1129);
UIImageView *imageView = [[UIImageView alloc] initWithImage: image];
[scrollView addSubview:imageView];
[self.view addSubview:scrollView];

Thanks

Answer 1

self.view in this case is the view containing the scrollview, so the scrollview fills the entire view when set to self.view.frame. Frame and content size are different things – frame of scrollview defines visible part of scrollview, and content size defines the size of scrollable (zoomable) content inside your scrollview.