（Swift）如何在单元格滑动操作中设置清晰的背景？ [英] (Swift) How to set clear background in cell swipe action?

问题描述

我在UITableViewCell中有一个trailingSwipeAction，其背景颜色必须清晰。

这是我设置动作的代码：

  func tableView（_ tableView：UITableView，trailingSwipeActionsConfigurationForRowAt indexPath：IndexPath） - > UISwipeActionsConfiguration？ {
 let myAction = UIContextualAction.init（style：.normal，title：nil）{
 //我的行动代码
} 
 myAction.backgroundColor = .clear 
 myAction.image = UIImage.init（名称：my-icon）
返回UISwipeActionsConfiguration.init（操作：[myAction]）
} 
  

但是当我没有预期的颜色时，我会得到灰色背景：

解决方案：

你可以查看应用程序在单元格上滑动的视图层次结构，然后在Xcode中转到 Debug 菜单，然后查看调试，并选择捕获视图层次结构。

首先，让我们添加这个有用的扩展获取数组中的所有子视图及其子视图：

 扩展UIView {
 var allSubViews：[UIView] {
 var array = [self.subviews] .flatMap {$ 0} 
 array.forEach {array.append（contentsOf：$ 0.allSubViews ）} 
返回数组
} 
} 
  

然后进入 viewWillLayoutSubviews（）：

 覆盖func viewWillLayoutSubviews（）{ 
 super.viewWillLayoutSubviews（）
 let btn = tableView 
 .allSubViews //获取所有子视图
 .first（where：{String（describe：type（of：$ 0）） ==UISwipeActionStandardButton}）//得到第一个是UISwipeActionStandardButton 
 
 //这个UISwipeActionStandardButton有两个子视图，在你的情况下，我得到的是一个不是UILabel的子视图，因为如果让view = btn？.subviews.first（其中：{！（$ 0是UILabel）}）
 {$ b}你设置了图像，你应该得到一个不是imageView 
的图像。 $ b view.backgroundColor = .clear //更改灰色uiview的背景颜色
} 
} 
  

我正在使用 viewWillLayoutSubviews（）因为它被调用以通知视图控制器它的视图即将布局其子视图。有关详细信息，请查看此处。

此解决方案针对一个滑动操作按钮进行了优化。如果您有多个按钮，代码将如下所示：

 覆盖func viewWillLayoutSubviews（）{
 super .viewWillLayoutSubviews（）
 let buttons = tableView 
 .allSubViews //获取所有子视图
 .filter {String（描述：type（of：$ 0））==UISwipeActionStandardButton} 
 
 buttons.forEach {btn in 
 if let view = btn.subviews.first（where：{！（$ 0 is UIImageView）}）//如果你确定除了uiview之外是UISwipeActionStandardButton的子视图中的UIImageView 
 {
 view.backgroundColor = .clear //更改灰色uiview的背景颜色
} 
} 
} 
  

I have a trailingSwipeAction in a UITableViewCell, whose background color must be clear.

This is the code where I set the action :

func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
    let myAction = UIContextualAction.init(style: .normal, title: nil) {
        // My action code
    }
    myAction.backgroundColor = .clear
    myAction.image = UIImage.init(named: "my-icon")
    return UISwipeActionsConfiguration.init(actions: [myAction])
}

But I am getting gray background for the action, when no color was expected:

SOLUTION: https://stackoverflow.com/a/52018193/9451152

解决方案

You'll have to access the UIView inside the UIActionStandardButton inside the UISwipeActionPullView. and then change its background color.

You can see the view hierarchy of your app swiping on a cell, then going the Debug menu in Xcode, then View Debugging, and choose Capture View Hierarchy.

First of all, let add this useful extension that gets all subviews and their subviews in an array:

extension UIView {
    var allSubViews : [UIView] {
        var array = [self.subviews].flatMap {$0}
        array.forEach { array.append(contentsOf: $0.allSubViews) }
        return array
    }
}

And then in viewWillLayoutSubviews():

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()
    let btn = tableView
              .allSubViews //get all the subviews
              .first(where: {String(describing:type(of: $0)) ==  "UISwipeActionStandardButton"}) // get the first one that is a UISwipeActionStandardButton

    //This UISwipeActionStandardButton has two subviews, I'm getting the one that is not a UILabel, in your case, since you've set the image,  you should get the one that is not an imageView
    if let view = btn?.subviews.first(where: { !($0 is UILabel)})
    {
        view.backgroundColor = .clear //Change the background color of the gray uiview
    }
}

I am using viewWillLayoutSubviews() since it's called to notify the view controller that its view is about to layout its subviews. Have a look here for more details.

This solution is optimized for one swipe action button. If you have more than one button, the code would look like this:

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()
    let buttons = tableView
        .allSubViews //get all the subviews
        .filter {String(describing:type(of: $0)) ==  "UISwipeActionStandardButton"}

    buttons.forEach { btn in
        if let view = btn.subviews.first(where: { !($0 is UIImageView)}) //If you're sure that other than the uiview there is a UIImageView in the subviews of the UISwipeActionStandardButton
        {
            view.backgroundColor = .clear //Change the background color of the gray uiview
        }
    }
}

这篇关于（Swift）如何在单元格滑动操作中设置清晰的背景？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！