如何在 Swift 中选择子视图时将子视图置于前面?

Question

所以我有两个视图，都以编程方式添加到超级视图中：

//First added view to my superView (baseView)
let imageViewOne = UIImageView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
baseView.addSubview(imageViewOne)
//Second added view to my superView (baseView)
let imageViewTwo = UIImageView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
baseView.addSubview(imageViewTwo)

我想在选择它时将其中一个放在前面，因为当您添加新视图时，它会与前一个视图重叠。与">选定"或"触摸">一起使用的内容。

Answer 1

使用这个：

baseView.bringSubview(toFront: imageViewOne)

Answer 2

您可以通过UITapGestureRecognizer通过从界面构建器设置恢复ID来执行此操作

func tapOneAct(sender: UITapGestureRecognizer) {
if(sender.view!.restorationIdentifier == "view1") 
// view1 is `Restoration ID` of imageViewOne
{
view.bringSubview(toFront: imageViewOne)
}
if(sender.view!.restorationIdentifier == "view2")
// view2 is `Restoration ID` of 2nd view
{
view.bringSubview(toFront: imageViewTwo)
}
}

Answer 3

如果我理解正确，那么您想检查所选视图的状态并将其放在视图层次结构的前面。 在这种情况下，您必须执行以下操作：

1(跟踪选择状态，让它在代码片段中var isSelected: Bool

2( 选择视图时按住操作的回调(例如可以使用UIButton来观察点击事件(

在下面的代码片段中，您可以在触摸视图时检查选择状态。

BaseView实现了用于检查SelectionView状态的逻辑。

import UIKit
final class SelectionView<T: UIView>: UIView {
var onTap: ((_ isSelected: Bool) -> ())?
// MARK: - Private
private let view: T
private let button = UIButton(type: .custom)
private var isSelected: Bool = false
// MARK: - Init
init(view: T) {
self.view = view
super.init(frame: .zero)
setUp()
}
// MARK: - Private
private func setUp() {
addSubview(view)
addSubview(button)
button.addTarget(self, action: #selector(onButtonTap), for: .touchUpInside)
}
@objc private func onButtonTap() {
isSelected = !isSelected
onTap?(isSelected)
}
// MARK: - Layout
override func layoutSubviews() {
super.layoutSubviews()
view.frame = bounds
button.frame = bounds
}
override func sizeThatFits(_ size: CGSize) -> CGSize {
return view.sizeThatFits(size)
}
// MARK: - Unused
override init(frame: CGRect) {
fatalError("init(frame:) has not been implemented")
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
final class BaseView: UIView {
init() {
super.init(frame: .zero)
let views = [SelectionView(view: UIView()), SelectionView(view: UIView())]
for view in views {
view.onTap = { [weak self, weak view] isSelected in
guard let selectedView = view
else { return }
if isSelected {
self?.bringSubview(toFront: selectedView)
}
}
}
}
// MARK: - Unused
override init(frame: CGRect) {
fatalError("init(frame:) has not been implemented")
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}