Ios SwiftUI:UIAlertController';在UIAlertAction中,s文本字段没有响应
我需要使用Ios SwiftUI:UIAlertController';在UIAlertAction中,s文本字段没有响应,ios,uikit,swiftui,uialertcontroller,uialertaction,Ios,Uikit,Swiftui,Uialertcontroller,Uialertaction,我需要使用UIAlertContoller,因为SwiftUI的Alert不支持TextField 由于各种原因(可访问性、DynamicType、暗模式支持等),我不能使用自定义创建的AlertView 基本思想是,SwiftUI的警报必须保持TextField&输入的文本必须反射回来以供使用。 我根据UIViewControllerRepresentable创建了一个SwiftUI视图,以下是工作代码 struct AlertControl: UIViewControllerRepresen
UIAlertContoller
,因为SwiftUI的Alert
不支持TextField
由于各种原因(可访问性、DynamicType、暗模式支持等),我不能使用自定义创建的AlertView
基本思想是,SwiftUI的警报必须保持TextField
&输入的文本必须反射回来以供使用。
我根据UIViewControllerRepresentable
创建了一个SwiftUI视图
,以下是工作代码
struct AlertControl: UIViewControllerRepresentable {
typealias UIViewControllerType = UIAlertController
@Binding var textString: String
@Binding var show: Bool
var title: String
var message: String
func makeUIViewController(context: UIViewControllerRepresentableContext<AlertControl>) -> UIAlertController {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addTextField { textField in
textField.placeholder = "Enter some text"
}
let cancelAction = UIAlertAction(title: "cancel", style: .destructive) { (action) in
self.show = false
}
let submitAction = UIAlertAction(title: "Submit", style: .default) { (action) in
self.show = false
}
alert.addAction(cancelAction)
alert.addAction(submitAction)
return alert
}
func updateUIViewController(_ uiViewController: UIAlertController, context: UIViewControllerRepresentableContext<AlertControl>) {
}
func makeCoordinator() -> AlertControl.Coordinator {
Coordinator(self)
}
class Coordinator: NSObject, UITextFieldDelegate {
var control: AlertControl
init(_ control: AlertControl) {
self.control = control
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if let text = textField.text {
self.control.textString = text
}
return true
}
}
}
// SwiftUI View in some content view
AlertControl(textString: self.$text,
show: self.$showAlert,
title: "Title goes here",
message: "Message goes here")
编辑:
cancelAction
或submitAction
不会在点击这些字段时触发。这里是解决方案的完整演示模块。使用Xcode 11.4/iOS 13.4进行测试
另请参见内联的重要注释
struct AlertControl: UIViewControllerRepresentable {
@Binding var textString: String
@Binding var show: Bool
var title: String
var message: String
func makeUIViewController(context: UIViewControllerRepresentableContext<AlertControl>) -> UIViewController {
return UIViewController() // holder controller - required to present alert
}
func updateUIViewController(_ viewController: UIViewController, context: UIViewControllerRepresentableContext<AlertControl>) {
guard context.coordinator.alert == nil else { return }
if self.show {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
context.coordinator.alert = alert
alert.addTextField { textField in
textField.placeholder = "Enter some text"
textField.text = self.textString // << initial value if any
textField.delegate = context.coordinator // << use coordinator as delegate
}
alert.addAction(UIAlertAction(title: "cancel", style: .destructive) { _ in
// your action here
})
alert.addAction(UIAlertAction(title: "Submit", style: .default) { _ in
// your action here
})
DispatchQueue.main.async { // must be async !!
viewController.present(alert, animated: true, completion: {
self.show = false // hide holder after alert dismiss
context.coordinator.alert = nil
})
}
}
}
func makeCoordinator() -> AlertControl.Coordinator {
Coordinator(self)
}
class Coordinator: NSObject, UITextFieldDelegate {
var alert: UIAlertController?
var control: AlertControl
init(_ control: AlertControl) {
self.control = control
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if let text = textField.text as NSString? {
self.control.textString = text.replacingCharacters(in: range, with: string)
} else {
self.control.textString = ""
}
return true
}
}
}
// Demo view for Alert Controll
struct DemoAlertControl: View {
@State private var text = ""
@State private var showAlert = false
var body: some View {
VStack {
Button("Alert") { self.showAlert = true }
.background(AlertControl(textString: self.$text, show: self.$showAlert,
title: "Title goes here", message: "Message goes here"))
Text(self.text)
}
}
}
struct AlertControl:UIViewControllerRepresentable{
@绑定变量textString:String
@绑定变量显示:Bool
变量标题:字符串
var消息:字符串
func makeUIViewController(上下文:UIViewControllerRepresentableContext)->UIViewController{
返回UIViewController()//保持器控制器-需要显示警报
}
func updateUIViewController(viewController:UIViewController,上下文:UIViewControllerRepresentableContext){
guard context.coordinator.alert==nil else{return}
如果自我表现{
let alert=UIAlertController(标题:标题,消息:消息,首选样式:。警报)
context.coordinator.alert=警报
alert.addTextField{textField in
textField.placeholder=“输入一些文本”
textField.text=self.textString//Bool{
如果让text=textField.text作为NSString{
self.control.textString=text.replacingCharacters(在:范围内,带:字符串)
}否则{
self.control.textString=“”
}
返回真值
}
}
}
//警报控制器的演示视图
结构DemoAlertControl:视图{
@国家私有变量text=“”
@状态私有变量showAlert=false
var body:一些观点{
VStack{
按钮(“警报”){self.showAlert=true}
.background(AlertControl)(文本字符串:self.$text,show:self.$showAlert,
标题:“标题在这里”,信息:“信息在这里”))
文本(self.Text)
}
}
}
感谢您的响应,但这并不能解决实际问题。取消操作
或提交操作
在点击这些按钮时不会触发。感谢@Asperi,这正按预期工作,但有时屏幕冻结&我在控制台中看到以下警告。2020-04-17 22:11:27.121106+0530 SwiftUI警报控制器[98884:3206838]警告:尝试呈现已呈现的内容(null)
总的来说,它解决了问题。再次感谢。@Nasir,在已经显示的警报中添加了守卫,以避免意外刷新。谢谢@Asperi,但我看不出coordinator中的守卫语句和警报实例的目的是什么,即使有上述更改,也会出现警告。似乎警报控制器已显示,但它从未关闭d、 在某个地方,我们要求解除呈现的警报。让我知道你的想法,我正在努力,一旦得出任何结论,我会更新。顺便说一句,谢谢你的努力。:@Nasir,你说的“永不解除”是什么意思?当我测试和演示时,警报按预期工作,并在任何按钮点击时解除。您是否使用不同的Xcode版本或条件?需要保护
,因为我们不控制SwiftUI在representable中调用update的时间,所以为了避免在警报已显示时发生冲突,我添加了保护并修改代码以存储警报。正如我使用在控制台中,我不再收到任何警告。
struct AlertControl: UIViewControllerRepresentable {
@Binding var textString: String
@Binding var show: Bool
var title: String
var message: String
func makeUIViewController(context: UIViewControllerRepresentableContext<AlertControl>) -> UIViewController {
return UIViewController() // holder controller - required to present alert
}
func updateUIViewController(_ viewController: UIViewController, context: UIViewControllerRepresentableContext<AlertControl>) {
guard context.coordinator.alert == nil else { return }
if self.show {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
context.coordinator.alert = alert
alert.addTextField { textField in
textField.placeholder = "Enter some text"
textField.text = self.textString // << initial value if any
textField.delegate = context.coordinator // << use coordinator as delegate
}
alert.addAction(UIAlertAction(title: "cancel", style: .destructive) { _ in
// your action here
})
alert.addAction(UIAlertAction(title: "Submit", style: .default) { _ in
// your action here
})
DispatchQueue.main.async { // must be async !!
viewController.present(alert, animated: true, completion: {
self.show = false // hide holder after alert dismiss
context.coordinator.alert = nil
})
}
}
}
func makeCoordinator() -> AlertControl.Coordinator {
Coordinator(self)
}
class Coordinator: NSObject, UITextFieldDelegate {
var alert: UIAlertController?
var control: AlertControl
init(_ control: AlertControl) {
self.control = control
}
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if let text = textField.text as NSString? {
self.control.textString = text.replacingCharacters(in: range, with: string)
} else {
self.control.textString = ""
}
return true
}
}
}
// Demo view for Alert Controll
struct DemoAlertControl: View {
@State private var text = ""
@State private var showAlert = false
var body: some View {
VStack {
Button("Alert") { self.showAlert = true }
.background(AlertControl(textString: self.$text, show: self.$showAlert,
title: "Title goes here", message: "Message goes here"))
Text(self.text)
}
}
}