我一直在努力使用Swift创建UIAlertView，但由于某种原因，我无法正确编写语句，因为我得到了这个错误：
找不到接受提供的参数的“init”重载
以下是我的编写方式:
let button2Alert: UIAlertView = UIAlertView(title: "Title", message: "message",
delegate: self, cancelButtonTitle: "OK", otherButtonTitles: nil)
然后我使用以下代码进行调用：
button2Alert.show()
截至目前它正在崩溃，我似乎无法正确地编写语法。
AlertView Swift 5 及以上版本：
let alert = UIAlertController(title: LocalizedStringConstant.alert, message: message, preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "Retry", style: .cancel, handler: { (_) in
}))
self.present(alert, animated: true, completion: nil)
我找到了这个,
var alertView = UIAlertView();
alertView.addButtonWithTitle("Ok");
alertView.title = "title";
alertView.message = "message";
alertView.show();
虽然不太好，但它能用 :)
更新:
但我在头文件中找到了如下内容：
extension UIAlertView {
convenience init(title: String, message: String, delegate: UIAlertViewDelegate?, cancelButtonTitle: String?, otherButtonTitles firstButtonTitle: String, _ moreButtonTitles: String...)
}
针对 iOS 13 Xcode 11+ Swift 5.X
UIAlertController 现在可以提供警告和操作表
警告
// First instantiate the UIAlertController
let alert = UIAlertController(title: "Title",
message: "Message ?",
preferredStyle: .alert)
// Add action buttons to it and attach handler functions if you want to
alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
alert.addAction(UIAlertAction(title: "Just Do It!", style: .destructive, handler: nil))
alert.addAction(UIAlertAction(title: "Maybe", style: .default, handler: nil))
// Show the alert by presenting it
self.present(alert, animated: true)
style参数仅用于决定文本的颜色（以及一些默认顺序，按钮的顺序可以更改）。func handler(_ action: UIAlertAction) {
if action.title == 'Title' {
// do stuff
}
}
alert.style，但这样我们就可以有多个默认样式的操作，我不建议这样做。
操作表
解释类似，因为主要区别在于警报会打断用户，而操作表会从底部滑动到 iPhone 上，在 iPad 上则呈现为弹出视图。let action = UIAlertController(title: "What do you want to do with the message",
message: nil,
preferredStyle: .actionSheet)
action.addAction(UIAlertAction(title: "Cancel", style: .cancel))
for act in ["Save", "Post", "Discard"] {
action.addAction(UIAlertAction(title: act, style: .default, handler: nil))
}
self.present(action, animated: true)
if let pop = action.popoverPresentationController {
let v = sender as! UIView
pop.sourceView = v
pop.sourceRect = v.bounds
}
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
}
}
或者像这样只有一个按钮的弹出窗口：
Popups.SharedInstance.ShowPopup("Title goes here", message: "Message goes here.")
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")
}
}
}
}
Swift 3
以下是使用 Swift 3 创建一个简单的带有一个按钮的警告框的示例。
let alert = UIAlertController(title: "Title",
message: "Message",
preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Ok", style: .default))
present(alert, animated: true)
let action = UIAlertAction(title: "Ok", style: .default) { action in
// Handle when button is clicked
}
我有一个小技巧。假设您有5个类需要应用注销警报。可以尝试使用Swift类扩展。
文件- 新建- Swift类- 命名。
添加以下内容：
public extension UIViewController
{
func makeLogOutAlert()
{
var refreshAlert = UIAlertController(title: "Log Out", message: "Are You Sure to Log Out ? ", preferredStyle: UIAlertControllerStyle.Alert)
refreshAlert.addAction(UIAlertAction(title: "Confirm", style: .Default, handler: { (action: UIAlertAction!) in
self.navigationController?.popToRootViewControllerAnimated(true)
}))
refreshAlert.addAction(UIAlertAction(title: "Cancel", style: .Default, handler: { (action: UIAlertAction!) in
refreshAlert .dismissViewControllerAnimated(true, completion: nil)
}))
presentViewController(refreshAlert, animated: true, completion: nil)
}
}
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)
}
我已经成功编译以下UIAlertView初始化代码（我认为最后的可变部分可能有些棘手）。但是，我必须确保self的类（我将其作为委托传递）正在采用UIAlertViewDelegate协议，以使编译错误消失：
let alertView = UIAlertView(
title: "My Title",
message: "My Message",
delegate: self,
cancelButtonTitle: "Cancel",
otherButtonTitles: "OK"
)
或者只需这样做
let alert = UIAlertController(title: "Alert", message: "Saved Successfully", preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertAction.Style.default, handler: nil))
self.present(alert, animated: true, completion: nil)
self所属的类采用了协议UIAlertViewDelegate（在Swift中，推荐的方法是使用扩展）。 - Nicolas Miari