How to add a UIImageVIew in UIScrollView Programatically in iOS?

Question

In my application I want to display a images in UIScrollview. Here I'm not getting the scrollview height and width as image height and width.How to get scrollview(Hight,Width) to my image view(height and width)? Here is upto now I had tried.

for (int i=0; i<imageArray.count; i++)
{
    NSString *str = [imageArray objectAtIndex:i];
    NSString *bannerImageURL = [NSString stringWithFormat:@"http:url/%@", str];
    CGFloat myOrigin = i * self.view.frame.size.width;
    UIImageView *myImageView = [[UIImageView alloc] initWithFrame:CGRectMake(myOrigin, 0, self.view.frame.size.width,imgScrollView.frame.size.height)];
    myImageView.contentMode = UIViewContentModeScaleAspectFit;
    myImageView.clipsToBounds = YES;
    myImageView.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:bannerImageURL]]];

    imgScrollView.contentSize = CGSizeMake(self.view.frame.size.width * imageArray.count,                                                               self.view.frame.size.height);


    CGPoint scrollPoint = CGPointMake(0, 0);

    [imgScrollView setContentOffset:scrollPoint animated:YES];
    imgScrollView.delegate = self;
    [imgScrollView addSubview:myImageView];

Here is my Delegate Methods.

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
[imgScrollView setContentOffset: CGPointMake(imgScrollView.contentOffset.x,0)];
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{

CGFloat pageWidth = scrollView.frame.size.width;
int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
NSLog(@"Scrolling - You are now on page %i",page);
}
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView
                 withVelocity:(CGPoint)velocity
  targetContentOffset:(inout CGPoint *) targetContentOffset
NS_AVAILABLE_IOS(5_0)
{
CGFloat pageWidth = scrollView.frame.size.width;
int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
NSLog(@"Dragging - You are now on page %i",page);
}

What I did mistake in my Code? Please Help me.

your question seems to be misleading. where did you call the for loop ? — Teja Nandamuri, Mar 02 '16 at 13:55
try calling it in viewWillAppear/viewDidAppear. Frame sizes are not yet calculated properly in view did load. — Teja Nandamuri, Mar 02 '16 at 13:57
[try to use available libs](https://www.cocoacontrols.com/controls/tapagecontrol)... [and more](https://www.cocoacontrols.com/search?q=pagecontrol) — Fahim Parkar, Mar 02 '16 at 13:59
did u log the scroll view frame and the img view fame ?@MangiReddy — Teja Nandamuri, Mar 02 '16 at 14:03
@TejaNandamuri. it's working fine in viewDidAppear method after clean my project.thanks for u r help. — User558, Mar 03 '16 at 05:19

score 1 · Answer 1 · answered Mar 02 '16 at 14:24

Theres several problems I can see. First the line

myImageView.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:bannerImageURL]]];

It might work but there are way too many nested calls on that line. You can't be sure which, if any, fail, if it happens. Separate it into 3 separate calls, so that you can step through and be sure its all working.

This line :

imgScrollView.contentSize = CGSizeMake(self.view.frame.size.width * imageArray.count,

Theres a Y value missing (probably paste issue) but also - you dont need to do this inside your for loop, you can just do it when you have finished adding all images. Same for setting the delegate - you dont need to do it every time. And setting the scroll point. All that should happen after the for loop.

Most importantly though, your implementation of the method scrollViewDidScroll has a call to setContentOffset. That will definitely not work. The call you make has the effect of scrolling the scrollview, which will therefore call the scrollViewDidScroll method again - you see the problem.

Most likely reason why your images arent appearing though is the first issue I mention - most likely your URL's are wrong somewhere, so you need to debug that by stepping through separate calls.

can you please select it as chosen answer then, and maybe upvote? would be appreciated @MangiReddy thanks :) — Luke Smith, Mar 03 '16 at 07:33

How to add a UIImageVIew in UIScrollView Programatically in iOS?

1 Answers1