如何让 UIButton 按下以在 Swift 中的 UICollectionViewCell 中工作? [英] How do I get a UIButton press to work in a UICollectionViewCell in Swift?

问题描述

所以这是一个 Swift 的 tvOS 项目.我有一个自定义 UICollectionViewCell ，带有一个按钮作为其子视图之一.我向按钮添加了一个目标以允许它解释点击.下面是相关代码的简化版

So this is a tvOS project in Swift. I have a custom UICollectionViewCell with a button as one of its subviews. I add a target to the button to allow it to interpret clicks. Here's a simplified version of the relevant code

class CustomCell: UICollectionViewCell {
    var button:UIButton!

    override init(frame: CGRect) {
        super.init(frame: frame)

        button = UIButton(...) // Button is initialized with a frame
        button.userInteractionEnabled = true
        button.enabled = true
        button.addTarget(self, action: "pressed:", forControlEvents: .PrimaryActionTriggered)
        contentView.addSubview(button)
    }

    func pressed(sender: UIButton!) {
        print("button pressed!")
    }
}

出于某种原因，它从未打印出我的消息.我尝试将pressedEnded"添加到单元格类中，以查看它是否有任何内容并被调用

For some reason it's not ever printing out my message. I tried adding 'pressedEnded' to the cell class to see if it's getting any and it gets called

func pressesEnded(presses: Set<UIPress>, withEvent event: UIPressesEvent?) {
        // If I put a breakpoint here it's reached
}

有什么建议吗?当我在模拟器中运行它时按钮可以获得焦点，所以我不知道为什么它无法获得任何事件

Any suggestions? When I run it in the simulator the button can get focus, so I don't know why it can't get any events

推荐答案

所以，我想出了如何解决这个问题，尽管它在某种程度上是一种解决方法.基本上对于 UICollectionView 我需要确保单元格的不能获得焦点.

So, I figured out how to solve this, although it's somewhat of a workaround. Basically for the UICollectionView I need to ensure the cell's can't get focus.

接下来，我之前在 CustomCell 中有 didUpdateFocusInContext.这就是 cell 时按钮的实际动画效果，但是当我检查按钮时，按钮从未获得焦点.我猜这是拦截它.因此，我从 CustomCell 中删除了该函数，而是在文件底部添加了该函数作为 UIButton 的扩展.

Next I had didUpdateFocusInContext in CustomCell previously. This was what was actually animating the button when the cell, but when I checked the button never got focus. I'm guessing this was intercepting it. So I removed that function from CustomCell and instead, at the bottom of my file I added that function as an extension of UIButton.

这也可以通过创建 UIButton 的子类并使用它来完成，但代码较少(这可能是理想的方式).所以完整的代码看起来像:

This also could've been done by creating a subclass of UIButton and using that instead, but this was less code (that is probably the ideal way). So the full code looks like:

class MyCollection: UICollectionView, UICollectionViewDelegate {
    // Need initializer functions as well as functions for creating CustomCell's. They're omitted because they're not relevant to the answer

    func collectionView(collectionView: UICollectionView, canFocusItemAtIndexPath indexPath: NSIndexPath) -> Bool {
        return false
    }  
}

class CustomCell: UICollectionViewCell {
    var button:UIButton!

    override init(frame: CGRect) {
        super.init(frame: frame)

        button = UIButton(...) // Button is initialized with a frame
        button.userInteractionEnabled = true
        button.enabled = true
        button.addTarget(self, action: "pressed:", forControlEvents: .PrimaryActionTriggered)
        self.addSubview(button)
    }

    func pressed(sender: UIButton!) {
        print("button pressed!")
    }
}

extension UIButton {
    override public func didUpdateFocusInContext(context: UIFocusUpdateContext, withAnimationCoordinator coordinator: UIFocusAnimationCoordinator) {
        super.didUpdateFocusInContext(context, withAnimationCoordinator: coordinator)

        if self.superview is CustomCell {   // This ensures that all UIButtons aren't affected
            if context.nextFocusedView == self {
                // Perform actions for when UIButton is focused
            }else {
                // Perform actions for when UIButton loses focus
            }
        }
    }
}

这篇关于如何让 UIButton 按下以在 Swift 中的 UICollectionViewCell 中工作?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！