Question

I need to create a UIButton programatically and then put it on a created UIScrollView and then put the UIScrollView on a UIView. If add these elements to self.view they are displayed, but when I want to nest then they are not displayed.
Here is what I have so far:

viewWithPictures=[[UIScrollView alloc] initWithFrame:self.bottomView.frame];
viewWithPictures.contentSize=CGSizeMake(160*[smallImagesFromGallery count], self.bottomView.frame.size.height);

viewWithPictures.backgroundColor=[UIColor greenColor];
NSLog(@"Number of small images: %i",[smallImagesFromGallery count]); 

for(int i=0; i<[smallImagesFromGallery count]; i++)
{
    UIButton *btn=[UIButton buttonWithType:UIButtonTypeCustom];

    btn.frame=CGRectMake(self.bottomView.frame.origin.x+i*160, self.bottomView.frame.origin.y, 150, 100);

    [btn setBackgroundImage:[smallImagesFromGallery objectAtIndex:i] forState:UIControlStateNormal];
    if (btn==nil) {
        NSLog(@"Button is nil");
    }
    btn.tag=i;
    [btn addTarget:self action:@selector(viewLargeVersion:) forControlEvents:UIControlEventTouchUpInside];
    [viewWithPictures addSubview:btn];



}
[bottomView addSubview:viewWithPictures];

Answer 1

When you’re setting the frame of a view that will become a subview, you need to reference the bounds of the view that it will be added to. So I think you need to change a couple of lines:

viewWithPictures=[[UIScrollView alloc] initWithFrame:self.bottomView.frame];

should be:

viewWithPictures=[[UIScrollView alloc] initWithFrame:self.bottomView.bounds];

and

btn.frame=CGRectMake(self.bottomView.frame.origin.x+i*160, self.bottomView.frame.origin.y, 150, 100);

should be:

btn.frame=CGRectMake(i*160, 0, 150, 100);