Disabling Horizontal Scrolling from UIScrollView S

问题:

Scroll View

I have a UIScrollView, with constraints left: 0, top: 0, right: 0, bottom: 0

Inside Scroll View

At the top of this UIScrollView is a UIImageView with constraints left: 0, top: 0, right: 0, height: 200

Underneath this I have a UITextView with constraints left: 0, top: 0, right: 0, bottom: 0

This means the UITextView will resize with respect to its content, and I set the scrollingEnabled to false for the UITextView.

So, when I run, it almost works perfectly.

The one problem is the UIImageView takes up about 10% more than the actual screen width. Hence, horizontal scrolling is enabled.

I have tried adding the lines

imageView.frame = CGRect(0, 0, screenSize.width, 200)
scrlView.contentSize.width = screenSize.width

but this makes no difference. I can still scroll horizontally and the Image View still takes up around 10% more than the actual screen width.

Note, I have not set imageView screen width in storyboard, only programatically.

Any ideas?

回答1:

Like this,

func scrollViewDidScroll(scrollView: UIScrollView) {
    if scrollView.contentOffset.x>0 {
        scrollView.contentOffset.x = 0
    }
}

And, you can set this property:

scrollImg.directionalLockEnabled = true

回答2:

The above only checks for X in one direction (positive movement). To prevent both left/right scrolling:

func scrollViewDidScroll(scrollView: UIScrollView) {
    if scrollView.contentOffset.x != 0 {
        scrollView.contentOffset.x = 0
    }
}

No need for the directional lock.

回答3:

Swift 4

Horizontal Scroll Lock

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if scrollView.contentOffset.x != 0 {
        scrollView.contentOffset.x = 0
    }
}

You can change the x to y for vertical scrolling.

Make sure to add UIScrollViewDelegate like this:

class MyViewController: UIViewController, UIScrollViewDelegate {

    @IBOutlet var scrollView: UIScrollView!

    ...
}

And set the delegate for the ScrollView

scrollView.delegate = self

回答4:

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    scrollView.contentOffset.x = 0
}

This stops the scrollview from scrolling towards the leading edge too.

回答5:

If you are using storyboard and autolayout, then you should consider how ScrollView work in Storyboard with autolayout.

Consider the following.

1. Add a single view on your scrollView with constrains left, right, top, bottom, height, width,

2. Make the outlet of the width and height

3. Add your subViews to the view you added in the scrollView

update the width to the screenSize eg: 320 for iPhone5 or 4.

self.viewWidth = SCREEN_WIDTH;
[self.view updateConstraints];