CODEWITHSUNDEEP
iosxcodeswiftuiscrollview
Costa
Costa

Reputation: 654

UIScrollView page width not equal self.view width

I have the code:

Why UIScrollView's page width not equal to self.view width?

If I think right, self.view.frame.size.width must be equal to scroll.bounds.width and scroll.contentSize must be self.view.frame.size.width*4 (at this case), is it right?

Thx a lot!!

class ViewController: UIViewController {

    @IBOutlet weak var scroll: UIScrollView!
    var frame: CGRect = CGRectMake(0, 0, 0, 0)

    override func viewDidLoad() {
        super.viewDidLoad()
        scroll.bounds = self.view.bounds
        scroll.frame = self.view.frame

        NSLog("%@", UIScreen.mainScreen().bounds.width);
        NSLog("%@", scroll.bounds.width);
                NSLog("%@", self.view.bounds.width);
        NSLog("%@", scroll.contentSize.width);


        let colors = [UIColor.redColor(), UIColor.greenColor(), UIColor.yellowColor(), UIColor.magentaColor()];

        for index in 0..<colors.count {

            frame.origin.x = self.view.frame.size.width * CGFloat(index)
            frame.size = self.view.frame.size

            var subView = UIView(frame: frame)
            subView.backgroundColor = colors[index]
            subView.layer.borderColor = UIColor.blackColor().CGColor
            subView.layer.borderWidth = 1.0;
            self.scroll .addSubview(subView)
        }

        scroll.contentSize = CGSizeMake(self.view.frame.size.width * CGFloat(colors.count), self.view.frame.size.height)          
    }
...  
}

What I see at second page: enter image description here

Upvotes: 0

Views: 815

Answers (1)

Lyndsey Scott
Lyndsey Scott

Reputation: 37290

(1) There's no need to set the bounds if you're going to set the frame one line later, so you can remove this line completely: scroll.bounds = self.view.bounds

(2) Move everything else in your viewDidLoad to viewDidLayoutSubviews since the frames you're setting are dependent on the view's width, which can change one the subviews have been laid out to fit the screen appropriately. But I'd also recommend only performing this code once by using a conditional since viewDidLayoutSubviews can be called multiple times and you should only be running this code once so as not to add extra subviews unnecessarily, ex:

@IBOutlet weak var scroll: UIScrollView!
var frame: CGRect = CGRectMake(0, 0, 0, 0)
var viewLaidout:Bool = false

override func viewDidLayoutSubviews() {

    if !viewLaidout {
        scroll.frame = self.view.frame

        let colors = [UIColor.redColor(), UIColor.greenColor(), UIColor.yellowColor(), UIColor.magentaColor()];

        for index in 0..<colors.count {

            frame.origin.x = self.view.frame.size.width * CGFloat(index)
            frame.size = self.view.frame.size

            var subView = UIView(frame: frame)
            subView.backgroundColor = colors[index]
            subView.layer.borderColor = UIColor.blackColor().CGColor
            subView.layer.borderWidth = 1.0;
            self.scroll.addSubview(subView)
        }

        scroll.contentSize = CGSizeMake(self.view.frame.size.width * CGFloat(colors.count), self.view.frame.size.height)
        viewLaidout = true
    }
}

Upvotes: 1

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