問題描述

我在一個(gè)頁面上有幾個(gè) UIScrollView.您可以單獨(dú)滾動(dòng)它們或?qū)⑺鼈冩i定在一起并將它們作為一個(gè)滾動(dòng).當(dāng)它們被鎖定時(shí)會(huì)出現(xiàn)問題.

I've got a a few UIScrollView on a page. You can scroll them independently or lock them together and scroll them as one. The problem occurs when they are locked.

我使用 UIScrollViewDelegate 和 scrollViewDidScroll: 來跟蹤運(yùn)動(dòng).我查詢 UIScrollView 的 contentOffset 已更改，然后通過將其 contentOffset 屬性設(shè)置為匹配來反映更改到其他滾動(dòng)視圖.

I use UIScrollViewDelegate and scrollViewDidScroll: to track movement. I query the contentOffset of the UIScrollView which changed and then reflect change to other scroll views by setting their contentOffset property to match.

太好了....除了我注意到很多額外的電話.以編程方式更改滾動(dòng)視圖的 contentOffset 會(huì)觸發(fā)委托方法 scrollViewDidScroll: 被調(diào)用.我嘗試使用 setContentOffset:animated: 代替，但我仍然在委托上獲得觸發(fā)器.

Great.... except I noticed a lot of extra calls. Programmatically changing the contentOffset of my scroll views triggers the delegate method scrollViewDidScroll: to be called. I've tried using setContentOffset:animated: instead, but I'm still getting the trigger on the delegate.

如何以編程方式修改我的 contentOffsets 以不觸發(fā) scrollViewDidScroll:?

How can I modify my contentOffsets programmatically to not trigger scrollViewDidScroll:?

實(shí)施說明....每個(gè) UIScrollView 都是自定義 UIView 的一部分，它使用委托模式回調(diào)處理協(xié)調(diào)各種 contentOffset 的呈現(xiàn) UIViewController 子類 值.

Implementation notes.... Each UIScrollView is part of a custom UIView which uses delegate pattern to call back to the presenting UIViewController subclass that handles coordinating the various contentOffset values.

推薦答案

可以在不觸發(fā)委托回調(diào)scrollViewDidScroll:的情況下改變UIScrollView的內(nèi)容偏移量，通過設(shè)置 UIScrollView 的邊界并將原點(diǎn)設(shè)置為所需的內(nèi)容偏移量.

It is possible to change the content offset of a UIScrollView without triggering the delegate callback scrollViewDidScroll:, by setting the bounds of the UIScrollView with the origin set to the desired content offset.

CGRect scrollBounds = scrollView.bounds;
scrollBounds.origin = desiredContentOffset;
scrollView.bounds = scrollBounds;

這篇關(guān)于以編程方式設(shè)置 contentOffset 觸發(fā) scrollViewDidScroll的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！