問題描述

如何讓兩個滾動視圖跟隨彼此滾動?

How would I make two scroll views follow each others scrolling?

例如，我在屏幕左側有一個滾動視圖 (A)，其內容可以上下滾動，但不能左右滾動.滾動視圖 B 匹配 A 的上下滾動，但也可以左右滾動.滾動視圖 A 始終在屏幕上.

For instance, I have a scroll view (A) on the left of a screen, whose contents can scroll up and down, but not left and right. Scroll view B matches the up and down of A, but can also scroll left and right. Scroll view A is always on the screen.

-----------------------------------------------------------
|             |                                           |
|             |                                           |
|             |                                           |
|     A       |                    B                      |
|             |                                           |
|    scrolls  |                                           |
|   up & down |              scrolls all directions       |
|             |                                           |
-----------------------------------------------------------

我將如何做到這一點，以便(任一視圖的)上下滾動也會使另一個視圖沿相同的上下方向滾動?還是有其他方法可以做到這一點?

How would I make it so the the up and down scrolling (of either view) also makes the other view scroll in the same up-down direction? Or is there another method to do this?

推薦答案

將滾動視圖 A 的委托設置為您的視圖控制器...然后...

Set the delegate of scroll view A to be your view controller... then have...

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
  CGPoint offset = scrollViewB.contentOffset;
  offset.y = scrollViewA.contentOffset.y;
  [scrollViewB setContentOffset:offset];
}

如果您希望雙方互相關注，則為他們設置委托并使用...

If you want both to follow each other, then set delegate for both of them and use...

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
  if([scrollView isEqual:scrollViewA]) {
    CGPoint offset = scrollViewB.contentOffset;
    offset.y = scrollViewA.contentOffset.y;
    [scrollViewB setContentOffset:offset];
  } else {
    CGPoint offset = scrollViewA.contentOffset;
    offset.y = scrollViewB.contentOffset.y;
    [scrollViewA setContentOffset:offset];
  }
}

上面可以重構為有一個方法，它接受兩個滾動視圖并匹配另一個.

The above can be refactored to have a method which takes in two scrollviews and matches one to the other.

- (void)matchScrollView:(UIScrollView *)first toScrollView:(UIScrollView *)second {
  CGPoint offset = first.contentOffset;
  offset.y = second.contentOffset.y;
  [first setContentOffset:offset];
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
  if([scrollView isEqual:scrollViewA]) {
    [self matchScrollView:scrollViewB toScrollView:scrollViewA];  
  } else {
    [self matchScrollView:scrollViewA toScrollView:scrollViewB];  
  }
}

Swift 3 版本:

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        if scrollView == scrollViewA {
            self.synchronizeScrollView(scrollViewB, toScrollView: scrollViewA)
        }
        else if scrollView == scrollViewB {
            self.synchronizeScrollView(scrollViewA, toScrollView: scrollViewB)
        }
    }

    func synchronizeScrollView(_ scrollViewToScroll: UIScrollView, toScrollView scrolledView: UIScrollView) {
        var offset = scrollViewToScroll.contentOffset
        offset.y = scrolledView.contentOffset.y

        scrollViewToScroll.setContentOffset(offset, animated: false)
    }

這篇關于使兩個 UIScrollViews 跟隨彼此滾動的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！