无法滚动到底部 UICollectionview

Question

我无法滚动到底部，我尝试了其他解决方案但没有成功。

我正在使用 IGLiskit

这是错误：

attempt to scroll to invalid index path

代码如下：

    func initMessages() {
    DataService.call.retrieveMessages(roomID: room.id ?? "") { (success, error, messages) in
        if !success {
            print("error", error!.localizedDescription)
        } else {
            guard let messages = messages else {return}
            self.messages = messages                
            DispatchQueue.main.async {
                self.adapter.performUpdates(animated: true, completion: nil)
                let indexPath = IndexPath(item: self.messages.count - 1, section: 0)
                self.collectionView.scrollToItem(at: indexPath, at: .bottom, animated: true)
            }
        }
    }
}

Answer 1

您在 collectionview 中有 2 个部分吗？是的，请忽略我的回答，我希望问题是您正在尝试访问第 1 部分，您只有第 0 部分可用，请尝试更改此代码：

func initMessages() {
    DataService.call.retrieveMessages(roomID: room.id ?? "") { (success, error, messages) in
        if !success {
            print("error", error!.localizedDescription)
        } else {
            guard let messages = messages else {return}
            self.messages = messages                
            DispatchQueue.main.async {
                self.adapter.performUpdates(animated: true, completion: nil)
                // Here in section
                let indexPath = IndexPath(item: self.messages.count - 1, section: 0)
                self.collectionView.scrollToItem(at: indexPath, at: .bottom, animated: true)
            }
        }
    }
}

编辑：好的，如果该部分不起作用，请尝试此扩展：

extension UICollectionView {
    func scrollToLast() {
        guard numberOfSections > 0 else {
            return
        }

        let lastSection = numberOfSections - 1

        guard numberOfItems(inSection: lastSection) > 0 else {
            return
        }

        let lastItemIndexPath = IndexPath(item: numberOfItems(inSection: lastSection) - 1,
                                          section: lastSection)
        scrollToItem(at: lastItemIndexPath, at: .bottom, animated: true)
    }
}

用法：

collectionView.scrollToLast()

无法滚动到底部 UICollectionview

Can' t scroll to bottom UICollectionview

ios

swift

uicollectionview

iglistkit