Question

How do I set the starting point of a UIScrollView? I would like to add a UIImageView left of the UIScrollView but changing the contentSize only adds scrolling room to the right of the scrollview. How do I add an ImageView left of the scrollView’s (0,0) point and make it part of the scrollview’s content size?

Answer 1

Hopefully I’ve got what you’re trying to do here. I think this just takes a few turns with the contentOffset to get right.

Starting off;

• Add the scrollView at frame (0,0,320,480) – its a full screen scroller
• set contentSize to (320*3, 480) – it now has a content with the width of 3 ‘pages’
• Add your imageView as a subview to the scrollView at frame (320,0,320,480)
• set contentOffset of the scrollView to (320, 0) – this will move the content of the scrollView left, in the negative x direction by 320
• Now your imageView will be on screen, but it will have a 320px width both on the left and right on the scroller content.

(Note that in the code below, i’ve simply added a UIView and not an imageView)

UIScrollView *scroller = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
scroller.delegate = self;
scroller.pagingEnabled = YES;
scroller.backgroundColor = [UIColor blueColor];
scroller.contentSize = CGSizeMake(960, 480);

UIView *imgView = [[UIView alloc] initWithFrame:CGRectMake(320, 0, 320, 480)];
[imgView setBackgroundColor:[UIColor redColor]];
[scroller addSubview:imgView];

[scroller setContentOffset:CGPointMake(320, 0)];
[self.view addSubview:scroller];

Does that help?