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。
SWIFT 4:简单地为UIViewController创建一个扩展,如下所示:
extension UIViewController {
func showSuccessAlert(withTitle title: String, andMessage message:String) {
let alert = UIAlertController(title: title, message: message,
preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "OK".localized, style:
UIAlertAction.Style.default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
}
现在在你的ViewController中,直接调用上面的函数,就好像它们是由UIViewController提供的一样。
yourViewController.showSuccessAlert(withTitle:
"YourTitle", andMessage: "YourCustomTitle")
通过Swift 2的协议扩展,你可以创建一个为视图控制器提供默认实现的协议:
ShowsAlert.swift
import UIKit
protocol ShowsAlert {}
extension ShowsAlert where Self: UIViewController {
func showAlert(title: String = "Error", message: String) {
let alertController = UIAlertController(title: title, message: message, preferredStyle: .Alert)
alertController.addAction(UIAlertAction(title: "Ok", style: .Default, handler: nil))
presentViewController(alertController, animated: true, completion: nil)
}
}
ViewController.swift
class ViewController: UIViewController, ShowsAlert {
override func viewDidLoad() {
super.viewDidLoad()
showAlert(message: "Hey there, I am an error message!")
}
}
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