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。
当前回答
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)
}
}
}
其他回答
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)
}
}
}
@IBAction func Alert(sender: UIButton) {
var alertView:UIAlertView = UIAlertView()
alertView.title = "Alert!"
alertView.message = "Message"
alertView.delegate = self
alertView.addButtonWithTitle("OK")
alertView.show()
}
试试这个
它不工作的原因是因为你传递给函数的某个值不正确。swift不像Objective-C，你可以把nil放在类类型的参数中，没有任何限制(可能是)。参数otherButtonTitles被定义为非可选的，其类型的末尾没有(?)。所以你必须传递一个具体的值给它。
使用此代码显示alertview
let alertController = UIAlertController(title: "Hello Coders", message: "your alert message", preferredStyle: .Alert)
let defaultAction = UIAlertAction(title: "Close Alert", style: .Default, handler: nil)
alertController.addAction(defaultAction)
presentViewController(alertController, animated: true, completion: nil)
Swift显示警报使用UIAlertController
我找到了这个，
var alertView = UIAlertView();
alertView.addButtonWithTitle("Ok");
alertView.title = "title";
alertView.message = "message";
alertView.show();
虽然不是很好，但它有效:)
更新:
但我在头文件上发现为:
extension UIAlertView {
convenience init(title: String, message: String, delegate: UIAlertViewDelegate?, cancelButtonTitle: String?, otherButtonTitles firstButtonTitle: String, _ moreButtonTitles: String...)
}
也许有人能解释一下。
