访问UICollectionView的父UIViewController [英] Access a UICollectionView's parent UIViewController

问题描述

我的问题相当简单。我有一个包含UICollectionView的UIViewController。在初始化我的单元格时，我为每个单元格添加了一个手势识别器，这样当您点击并按住它时，可以使用选择器调用一个函数。

My question is fairly straightforward. I have a UIViewController containing a UICollectionView. In initialising my cells, I add a gesture recogniser to each of them so that when you tap and hold it calls a function with a selector.

然后，此函数创建一个我想要呈现的UIAlertController。 （基本上，你持有一个单元格，它会询问你是否要删除它，如果你说是，它会从CollectionView中删除它）

This function then creates a UIAlertController which I want to present. (Basically, you hold a cell, it asks you if you want to delete it and if you say yes it eliminates it from the CollectionView)

问题是我可以从我的UICollectionView呈现UIAlertController，因为它不是ViewController。

The problem is that I can't present a UIAlertController from my UICollectionView because it isn't a ViewController.

我想以编程方式获取包含UICollectionView的UIViewController，以便从一个函数中显示此警报在UICollectionView实现中。

I want to programmatically get the UIViewController that contains the UICollectionView to present this alert from a function that is inside the UICollectionView implementation.

推荐答案

我通过在自定义 UICollectionViewCell中制作协议来实现此目的并将这些事件委托回 UIViewController ，类似这样的事情

I do this by making a protocol in my custom UICollectionViewCell and delegate these events back to the UIViewController, something like this

在你的 MyCollectionViewCell

In your MyCollectionViewCell

protocol MyCollectionViewCellDelegate: class {
    func didLongPressCell()
}

class MyCollectionViewCell:UICollectionViewCell {

    weak var delegate:MyCollectionViewCellDelegate?

    func longPressAction() {
        if let del = self.delegate {
            del.didLongPressCell
        }
    }

}

然后返回 MyViewController

Then back in your MyViewController

class MyViewController:UIViewController, MyCollectionViewCellDelegate {

    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath) as! MyCollectionViewCell
        cell.delegate = self
        return cell
    }

    func didLongPressCell() {
        // do what you want with the event from the cell here
    }

}

要记住的重要事项是设置每个单元格的委托

The important bits to remember are to set the delegate for each cell

cell.delegate = self

并在视图控制器中采用您想要接收事件的新协议

And adopt your new protocol in the view controller that you want to receive the events in

class MyViewController：UIViewController，MyCollectionViewCellDelegate

我还没有测试过这段代码，我不确定在每个单元格中存储对viewController的引用的最佳实践，但我做了一些非常相似的事情，让我知道你是怎么过的。

编辑：如果您已将 UICollectionView 子类化，则将其传递给视图控制器，以便您可以像s一样使用它o。

if you have subclassed your UICollectionView then pass it a reference to the view controller so that you can use it like so.

您的 MyViewController 现在看起来像这样

Your MyViewController would now look like this

class MyViewController:UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        let collectionView = MyCollectionView()
        collectionView.viewController = self
        self.view.addSubview(collectionView)
    }

}

您的自定义集合视图 MyCollectionView

And your custom collection view MyCollectionView

class MyCollectionView:UICollectionView, MyCollectionViewCellDelegate {

    weak var viewController:UIViewController?

    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath) as! MyCollectionViewCell
        cell.delegate = self
        return cell
    }

    func didLongPressCell() {
        if let vc = self.viewController {
            // make use of the reference to the view controller here
        }
    }

}

UICollectionViewCell 与以前相同

The UICollectionViewCell would be the same as before

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