Question

I can add several scrollviews with its background colours changed and it works fine. So basically for every view you have different background colours. However when I try to add separate views for each of these, it adds it right on top of the other and I don’t know why.

UIViewController *view1 = [self.storyboard instantiateViewControllerWithIdentifier:@"View1"];
UIViewController *view2 = [self.storyboard instantiateViewControllerWithIdentifier:@"View2"];
UIViewController *view3 = [self.storyboard instantiateViewControllerWithIdentifier:@"View3"];


for (NSInteger i=0; i<ScrollViewControllerNumberOfPages; i++) {
    CGFloat yOrigin = i * self.view.frame.size.height;
    CGRect subViewFrame = CGRectMake(yOrigin, 0, pageHeight, pageWidth);
    NSLog(@"Printing Width and Height %f  %f",pageWidth,pageHeight);
    UIView *subView = [[UIView alloc] initWithFrame:subViewFrame];

    // Pick a random colour for the view
    CGFloat randomRed = ((CGFloat)(arc4random() % 1000))/1000;
    CGFloat randomGreen = ((CGFloat)(arc4random() % 1000))/1000;
    CGFloat randomBlue = ((CGFloat)(arc4random() % 1000))/1000;
    subView.backgroundColor = [UIColor colorWithRed:randomRed green:randomGreen blue:randomBlue alpha:1];
    NSLog(@"printin i %i", i);
    if (i == 0)
    subView = view1.view;
    else if (i == 1)
        subView = view2.view;
[self.scrollView addSubview:subView];
}

Answer 1

This is kind of a shot in the dark because your code would need some serious rethinking.

What you’re doing is you allocate a subview, you modify it’s frame and background and then completely disregard this and set it to a view of previously instantiated viewcontoller.

This should work (in a way):

UIViewController *view1 = [self.storyboard instantiateViewControllerWithIdentifier:@"View1"];
UIViewController *view2 = [self.storyboard instantiateViewControllerWithIdentifier:@"View2"];
UIViewController *view3 = [self.storyboard instantiateViewControllerWithIdentifier:@"View3"];

for (NSInteger i=0; i<ScrollViewControllerNumberOfPages; i++) {
    CGFloat yOrigin = i * self.view.frame.size.height;
    CGRect subViewFrame = CGRectMake(yOrigin, 0, pageHeight, pageWidth);
    NSLog(@"Printing Width and Height %f  %f",pageWidth,pageHeight);

    UIView *subView;

    if (i == 0)
      subView = view1.view;
    else if (i == 1)
      subView = view2.view;

    subView.frame = subViewFrame;

    // Pick a random colour for the view
    CGFloat randomRed = ((CGFloat)(arc4random() % 1000))/1000;
    CGFloat randomGreen = ((CGFloat)(arc4random() % 1000))/1000;
    CGFloat randomBlue = ((CGFloat)(arc4random() % 1000))/1000;
    subView.backgroundColor = [UIColor colorWithRed:randomRed green:randomGreen blue:randomBlue alpha:1];
    NSLog(@"printin i %d", i);
    [self.scrollView addSubview:subView];
}

It might look a bit better if you do it like:

for (NSInteger i=0; i<ScrollViewControllerNumberOfPages; i++) {
    CGFloat yOrigin = i * self.view.frame.size.height;
    CGRect subViewFrame = CGRectMake(yOrigin, 0, pageHeight, pageWidth);
    NSLog(@"Printing Width and Height %f  %f",pageWidth,pageHeight);

    UIViewController *subViewCont = [self.storyboard instantiateViewControllerWithIdentifier:[NSString stringWithFormat:@"View%d",i+1]];

    UIView *subView = subViewCont.view;

    subView.frame = subViewFrame;

    // Pick a random colour for the view
    CGFloat randomRed = ((CGFloat)(arc4random() % 1000))/1000;
    CGFloat randomGreen = ((CGFloat)(arc4random() % 1000))/1000;
    CGFloat randomBlue = ((CGFloat)(arc4random() % 1000))/1000;
    subView.backgroundColor = [UIColor colorWithRed:randomRed green:randomGreen blue:randomBlue alpha:1];
    NSLog(@"printin i %d", i);
    [self.scrollView addSubview:subView];
}