我一直在努力创建一个UIAlertView在Swift,但由于某种原因,我不能得到正确的声明,因为我得到这个错误:
无法找到一个超载的'init'接受提供的
参数
我是这样写的:
let button2Alert: UIAlertView = UIAlertView(title: "Title", message: "message",
delegate: self, cancelButtonTitle: "OK", otherButtonTitles: nil)
然后我使用:
button2Alert.show()
到目前为止,它正在崩溃,我只是不能得到正确的语法。
你可以使用这个简单的扩展与n个按钮和相关的动作swift4以上
extension UIViewController {
func popupAlert(title: String?, message: String?, actionTitles:[String?], actions:[((UIAlertAction) -> Void)?]) {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
for (index, title) in actionTitles.enumerated() {
let action = UIAlertAction(title: title, style: .default, handler: actions[index])
alert.addAction(action)
}
self.present(alert, animated: true, completion: nil)
}
}
你可以这样使用它,
self.popupAlert(title: "Message", message: "your message", actionTitles: ["first","second","third"], actions:[
{action1 in
//action for first btn click
},
{action2 in
//action for second btn click
},
{action3 in
//action for third btn click
}, nil])
下面是警报视图和动作表的可重用代码,只需写一行在应用程序的任何地方显示警报
class AlertView{
static func show(title:String? = nil,message:String?,preferredStyle: UIAlertControllerStyle = .alert,buttons:[String] = ["Ok"],completionHandler:@escaping (String)->Void){
let alert = UIAlertController(title: title, message: message, preferredStyle: preferredStyle)
for button in buttons{
var style = UIAlertActionStyle.default
let buttonText = button.lowercased().replacingOccurrences(of: " ", with: "")
if buttonText == "cancel"{
style = .cancel
}
let action = UIAlertAction(title: button, style: style) { (_) in
completionHandler(button)
}
alert.addAction(action)
}
DispatchQueue.main.async {
if let app = UIApplication.shared.delegate as? AppDelegate, let rootViewController = app.window?.rootViewController {
rootViewController.present(alert, animated: true, completion: nil)
}
}
}
}
用法:
class ViewController: UIViewController {
override func viewWillAppear(_ animated: Bool) {
AlertView.show(title: "Alert", message: "Are you sure ?", preferredStyle: .alert, buttons: ["Yes","No"]) { (button) in
print(button)
}
}
}
我已经做了一个单例类,以便从应用程序的任何地方使用:https://github.com/Swinny1989/Swift-Popups
然后你可以创建一个带有多个按钮的弹出窗口,如下所示:
Popups.SharedInstance.ShowAlert(self, title: "Title goes here", message: "Messages goes here", buttons: ["button one" , "button two"]) { (buttonPressed) -> Void in
if buttonPressed == "button one" {
//Code here
} else if buttonPressed == "button two" {
// Code here
}
}
或者弹出一个按钮,像这样:
Popups.SharedInstance.ShowPopup("Title goes here", message: "Message goes here.")
点击查看
@IBAction func testClick(sender: UIButton) {
var uiAlert = UIAlertController(title: "Title", message: "Message", preferredStyle: UIAlertControllerStyle.Alert)
self.presentViewController(uiAlert, animated: true, completion: nil)
uiAlert.addAction(UIAlertAction(title: "Ok", style: .Default, handler: { action in
println("Click of default button")
}))
uiAlert.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: { action in
println("Click of cancel button")
}))
}
完成两个按钮确定&取消
对于SWIFT4,我认为扩展UIViewController并创建一个可重用的确认控件是最优雅的方式。
你可以像下面这样扩展UIViewController:
extension UIViewController {
func AskConfirmation (title:String, message:String, completion:@escaping (_ result:Bool) -> Void) {
let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.alert)
self.present(alert, animated: true, completion: nil)
alert.addAction(UIAlertAction(title: "Ok", style: .default, handler: { action in
completion(true)
}))
alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: { action in
completion(false)
}))
}
}
那么你可以随时使用它:
AskConfirmation(title: "YOUR MESSAGE TITLE", message: "YOUR MESSAGE") { (result) in
if result { //User has clicked on Ok
} else { //User has clicked on Cancel
}
}
斯威夫特3
下面是一个简单的例子,如何用Swift 3一个按钮创建一个简单的警报。
let alert = UIAlertController(title: "Title",
message: "Message",
preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Ok", style: .default))
present(alert, animated: true)
在上面的例子中,动作的句柄回调被省略了,因为带有一个按钮的警报视图的默认行为是在单击按钮时消失。
下面是如何创建另一个动作,可以用"alert. addaction (action)"添加到警报中。不同的样式是.default, .destructive和.cancel。
let action = UIAlertAction(title: "Ok", style: .default) { action in
// Handle when button is clicked
}