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
// UIAlertView的自定义类
//MARK:- MODULES
import Foundation
import UIKit
//MARK:- CLASS
class Alert : NSObject{
static let shared = Alert()
var okAction : AlertSuccess?
typealias AlertSuccess = (()->())?
var alert: UIAlertController?
/** show */
public func show(title : String?, message : String?, viewController : UIViewController?, okAction : AlertSuccess = nil) {
let version : NSString = UIDevice.current.systemVersion as NSString
if version.doubleValue >= 8 {
alert = UIAlertController(title: title, message: message, preferredStyle:.alert)
alert?.addAction(UIAlertAction(title: "OK", style: .default, handler: { (action: UIAlertAction) in
if let okAction = okAction {
okAction()
}
}))
viewController?.present(alert ?? UIAlertController(), animated:true, completion:nil);
}
}
/** showWithCancelAndOk */
public func showWithCancelAndOk(title : String, okTitle : String, cancelTitle : String, message : String, viewController : UIViewController?, okAction : AlertSuccess = nil, cancelAction : AlertSuccess = nil) {
let version:NSString = UIDevice.current.systemVersion as NSString;
if version.doubleValue >= 8 {
alert = UIAlertController(title: title, message: message, preferredStyle:.alert)
alert?.addAction(UIAlertAction(title: cancelTitle, style: .default, handler: { (action: UIAlertAction) in
if let cancelAction = cancelAction {
cancelAction()
}
}))
alert?.addAction(UIAlertAction(title: okTitle, style: .default, handler: { (action: UIAlertAction) in
if let okAction = okAction {
okAction()
}
}))
viewController?.present(alert!, animated:true, completion:nil);
}
}
/** showWithTimer */
public func showWithTimer(message : String?, viewController : UIViewController?) {
let version : NSString = UIDevice.current.systemVersion as NSString
if version.doubleValue >= 8 {
alert = UIAlertController(title: "", message: message, preferredStyle:.alert)
viewController?.present(alert ?? UIAlertController(), animated:true, completion:nil)
let when = DispatchTime.now() + 1
DispatchQueue.main.asyncAfter(deadline: when){
self.alert?.dismiss(animated: true, completion: nil)
}
}
}
}
使用:
Alert.shared.show(title: "No Internet Connection", message: "The internet connection appers to be offline.", viewController: self) //without ok action
Alert.shared.show(title: "No Internet Connection", message: "The internet connection appers to be offline.", viewController: self, okAction: {
//ok action
}) // with ok action
Alert.shared.show(title: "No Internet Connection", message: "The internet connection appers to be offline.", viewController: self, okAction: {
//ok action
}, cancelAction: {
//cancel action
}) //with cancel and ok action
Alert.shared.showWithTimer(message : "This is an alert with timer", viewController : self) //with timer
其他回答
let alertController = UIAlertController(title: "Select Photo", message: "Select atleast one photo", preferredStyle: .alert)
let action1 = UIAlertAction(title: "From Photo", style: .default) { (action) in
print("Default is pressed.....")
}
let action2 = UIAlertAction(title: "Cancel", style: .cancel) { (action) in
print("Cancel is pressed......")
}
let action3 = UIAlertAction(title: "Click new", style: .default) { (action) in
print("Destructive is pressed....")
}
alertController.addAction(action1)
alertController.addAction(action2)
alertController.addAction(action3)
self.present(alertController, animated: true, completion: nil)
}
class Preview: UIViewController , UIAlertViewDelegate
{
@IBAction func MoreBtnClicked(sender: AnyObject)
{
var moreAlert=UIAlertView(title: "Photo", message: "", delegate: self, cancelButtonTitle: "No Thanks!", otherButtonTitles: "Save Image", "Email", "Facebook", "Whatsapp" )
moreAlert.show()
moreAlert.tag=111;
}
func alertView(alertView: UIAlertView, didDismissWithButtonIndex buttonIndex: Int)
{
if alertView.tag==111
{
if buttonIndex==0
{
println("No Thanks!")
}
else if buttonIndex==1
{
println("Save Image")
}
else if buttonIndex == 2
{
println("Email")
}
else if buttonIndex == 3
{
println("Facebook")
}
else if buttonIndex == 4
{
println("Whatsapp")
}
}
}
}
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。
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
}
}
一个按钮
class ViewController: UIViewController {
@IBAction func showAlertButtonTapped(_ sender: UIButton) {
// create the alert
let alert = UIAlertController(title: "My Title", message: "This is my message.", preferredStyle: UIAlertController.Style.alert)
// add an action (button)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil))
// show the alert
self.present(alert, animated: true, completion: nil)
}
}
两个按钮
class ViewController: UIViewController {
@IBAction func showAlertButtonTapped(_ sender: UIButton) {
// create the alert
let alert = UIAlertController(title: "UIAlertController", message: "Would you like to continue learning how to use iOS alerts?", preferredStyle: UIAlertController.Style.alert)
// add the actions (buttons)
alert.addAction(UIAlertAction(title: "Continue", style: UIAlertAction.Style.default, handler: nil))
alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertAction.Style.cancel, handler: nil))
// show the alert
self.present(alert, animated: true, completion: nil)
}
}
三个按钮
class ViewController: UIViewController {
@IBAction func showAlertButtonTapped(_ sender: UIButton) {
// create the alert
let alert = UIAlertController(title: "Notice", message: "Lauching this missile will destroy the entire universe. Is this what you intended to do?", preferredStyle: UIAlertController.Style.alert)
// add the actions (buttons)
alert.addAction(UIAlertAction(title: "Remind Me Tomorrow", style: UIAlertAction.Style.default, handler: nil))
alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertAction.Style.cancel, handler: nil))
alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertAction.Style.destructive, handler: nil))
// show the alert
self.present(alert, animated: true, completion: nil)
}
}
处理按钮
在上面的例子中，处理程序为nil。当用户点击按钮时，你可以用一个闭包来替换nil。例如:
alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertAction.Style.destructive, handler: { action in
// do something like...
self.launchMissile()
}))
笔记
多个按钮不一定需要使用不同的UIAlertAction。风格类型。它们都可以是。default。 对于超过三个按钮，可以考虑使用动作表。设置非常相似。这里有一个例子。
