Random Image via UIScrollView

lukeirvin · 10-12-2011, 03:58 PM

I have two UIScrollViews in my app, each with it's own unique set of images (scroll left/right to view them).

I want to be able to tap my UIBarButtonItem and it will create the effect of each scroll view autoscrolling and then each selecting a random image.

Does anyone know of a tutorial on this or can give me an explanation of how to go about this?

Thanks!

**baja_yu** · 10-12-2011, 10:22 PM

Just generate a random number from 0 to however-many-images-you-have-minus-one, and then animate the scrollview to the point equal (scrollview width * random number). Scrollviews have methods for that so check the documentation.

lukeirvin · 10-13-2011, 01:20 PM

I'm using this and it's working fine:

Code:

- (IBAction)mixButtonTapped:(id)sender
{
    if (arc4random() % kNumImagesTops && arc4random() % kNumImagesBottoms) 
    {
        [topsScrollView setContentOffset:CGPointMake(320, 0) animated:YES];
        [bottomsScrollView setContentOffset:CGPointMake(320, 0) animated:YES];
    }
}

My next problem is creating an Infinite Scroll.

Is this based on how you adjust the width alone or specifying how the images will be placed?

**baja_yu** · 10-13-2011, 02:05 PM

Why would you need an infinite scroll? Just asking because if you're taking a random image then there must be a finite number of images.

As a side note, there's an infinite scroll sample code called StreetScroller in the docs, but it requires the latest Xcode and SDK, not sure why, haven't tried it yet.

lukeirvin · 10-13-2011, 04:31 PM

Once this project is completed there will be a lot of images.

I'm not sure if an infinite scroll is really needed but I'd like to implement it.

Right now though it's not selected a random image, it's going to the last image.

Based on my code posted can anyone see why?

I have been working with Apple's sample code some today. I just can't get it working for images yet.