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问题:
I'm trying to create uialertcontroller in Config.swift file as follow.
static func showAlertMessage(titleStr:String, messageStr:String) -> Void {
let window : UIWindow?
let alert = UIAlertController(title: titleStr, message: messageStr, preferredStyle: UIAlertControllerStyle.Alert);
self.window!.presentViewController(alert, animated: true, completion: nil)
}
problem is I've found problem in self.window!.
Type 'Config' has no member 'window'
Please let me know how to solve that issue.
回答1:
self.window would mean that there's a window object in this class, and it's not the case.
You would need to use your let window : UIWindow? with window?.presentViewController(alert, animated: true, completion: nil), but this won't help, since this window does not actually represent any existing window, and it's not a view controller anyway.
So I suggest you pass the actual view controller you'll be using to the method:
static func showAlertMessage(vc: UIViewController, titleStr:String, messageStr:String) -> Void {
let alert = UIAlertController(title: titleStr, message: messageStr, preferredStyle: UIAlertControllerStyle.Alert);
vc.presentViewController(alert, animated: true, completion: nil)
}
and you call it from a class where a UIViewController object is available.
回答2:
swift
Here's what I used, this is the same as @penatheboss answered, just add the ability of adding actions and handlers.
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)
}
}
Just make sure actionTitles and actions array the same count. Pass nil if you don't need any action handler closure.
self.popupAlert(title: "Title", message: " Oops, xxxx ", actionTitles: ["Option1","Option2","Option3"], actions:[{action1 in
},{action2 in
}, nil])
Objective C:
Add the category for UIViewController
UIViewController+PopAlert.h
#import <UIKit/UIKit.h>
@interface UIViewController (UIViewControllerCategory)
- (void) popAlertWithTitle: (NSString*) title message: (NSString*) message actionTitles:(NSArray *) actionTitles actions:(NSArray*)actions;
@end
UIViewController+PopAlert.m
#import "UIViewController+PopAlert.h"
@implementation UIViewController (UIViewControllerCategory)
- (void) popAlertWithTitle: (NSString*) title message: (NSString*) message actionTitles:(NSArray *) actionTitles actions:(NSArray*)actions {
UIAlertController *alert = [UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleAlert];
[actionTitles enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
UIAlertAction *action = [UIAlertAction actionWithTitle:obj style:UIAlertActionStyleDefault handler:actions[idx]];
[alert addAction:action];
}];
[self presentViewController:alert animated:YES completion:nil];
}
@end
Usage:
#import UIViewController+PopAlert.h
...
[super viewDidDisappear:animated];
NSArray *actions = @[^(){NSLog(@"I am action1");}, ^(){NSLog(@"I am action2");}];
[self popAlertWithTitle:@"I am title" message:@"good" actionTitles:@[@"good1", @"good2"] actions:actions];
回答3:
I suggest creating an extension:
extension UIViewController {
func showAlertMessage(titleStr:String, messageStr:String) {
let alert = UIAlertController(title: titleStr, message: messageStr, preferredStyle: UIAlertControllerStyle.Alert)
self.presentViewController(alert, animated: true, completion: nil)
}
}
回答4:
You can try this, please add below code in AppDelegate.swift file.
static func showAlertView(vc : UIViewController, titleString : String , messageString: String) ->()
{
let alertView = UIAlertController(title: titleString, message: messageString, preferredStyle: .alert)
let alertAction = UIAlertAction(title: "ok", style: .cancel) { (alert) in
vc.dismiss(animated: true, completion: nil)
}
alertView.addAction(alertAction)
vc.present(alertView, animated: true, completion: nil)
}
and call showAlertView method from any viewcontroller
AppDelegate.showAlertView(vc: self, titleString: "testTitle", messageString: "test msg")
回答5:
I created a alerMessage class .I can call any where in my application
//Common Alert Message Class
class AlertMessage {
internal static var alertMessageController:UIAlertController!
internal static func disPlayAlertMessage(titleMessage:String, alertMsg:String){
AlertMessage.alertMessageController = UIAlertController(title: titleMessage, message:
alertMsg, preferredStyle: UIAlertControllerStyle.Alert)
AlertMessage.alertMessageController.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default,handler: nil))
if let controller = UIApplication.sharedApplication().keyWindow?.rootViewController?.presentedViewController {
controller.presentViewController(AlertMessage.alertMessageController, animated: true, completion: nil)
}
else{
UIApplication.sharedApplication().delegate?.window!!.rootViewController?.presentViewController(AlertMessage.alertMessageController, animated: true, completion: nil)
}
return
}
}
回答6:
Please refer the below GIT Example
https://github.com/amilaim/CommonAlertView
// ViewController.swift
// CommonAlertView
//
// Created by Amila Munasinghe on 4/25/17.
// Copyright © 2017 Developer Insight. All rights reserved.
//
import UIKit
class ViewController: UIViewController,AlertViewControllerDelegate {
@IBOutlet weak var AlertViewResultTextOutlet: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
@IBAction func ShowAlertAction(_ sender: Any) {
let alert = AlertViewController.sharedInstance
alert.delegate = self
alert.SubmitAlertView(viewController: self,title: "Developer Insight", message: "Please enter any text value")
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func SubmitAlertViewResult(textValue : String) {
AlertViewResultTextOutlet.text = textValue
}
}
Common UIAlertViewController Implementation
import UIKit
protocol AlertViewControllerDelegate {
func SubmitAlertViewResult(textValue : String)
}
class AlertViewController {
static let sharedInstance = AlertViewController()
private init(){}
var delegate : AlertViewControllerDelegate?
func SubmitAlertView(viewController : UIViewController,title : String, message : String){
let alert = UIAlertController(title: title,
message: message,
preferredStyle: .alert)
// Submit button
let submitAction = UIAlertAction(title: "Submit", style: .default, handler: { (action) -> Void in
// Get 1st TextField's text
let textField = alert.textFields![0]
if(textField.text != "")
{
self.delegate?.SubmitAlertViewResult(textValue: textField.text!)
}
})
// Cancel button
let cancel = UIAlertAction(title: "Cancel", style: .destructive, handler: { (action) -> Void in })
// Add 1 textField and cutomize it
alert.addTextField { (textField: UITextField) in
textField.keyboardAppearance = .dark
textField.keyboardType = .default
textField.autocorrectionType = .default
textField.placeholder = "enter any text value"
textField.clearButtonMode = .whileEditing
}
// Add action buttons and present the Alert
alert.addAction(submitAction)
alert.addAction(cancel)
viewController.present(alert, animated: true, completion: nil)
}
}
回答7:
What I'm using based on the solution by @William Hu:
func popup(caller:UIViewController, style:UIAlertControllerStyle? = UIAlertControllerStyle.alert,
title:String, message:String, buttonTexts:[String], buttonStyles:([UIAlertActionStyle?])? = nil,
handlers:[((UIAlertAction) -> Void)?], animated:Bool? = nil, completion: (() -> Void)? = nil) {
let alert = UIAlertController(title: title, message: message, preferredStyle: style!)
for i in 0..<buttonTexts.count {
alert.addAction(UIAlertAction(title: buttonTexts[i],
style: (buttonStyles == nil || i >= buttonStyles!.count || buttonStyles![i] == nil ?
UIAlertActionStyle.default : buttonStyles![i]!),
handler: (i >= handlers.count || handlers[i] == nil ? nil : handlers[i]!)))
}
caller.present(alert, animated: animated != nil ? animated! : true, completion: completion)
}
- Single function gives
Alert by default and can optionally be used for ActionSheet.
- Arrays
buttonTexts, buttonStyles and handlers can be of unequal sizes as per requirement.
Actions can be styled.Animated can be specified. - Optional
block can be specified to be executed when presentation finishes.
Usage:
popup(caller: self, style: UIAlertControllerStyle.alert,
title: "Title", message: "Message",
buttonTexts: ["Destructive", "Cancel", "OK"],
buttonStyles: [UIAlertActionStyle.destructive, UIAlertActionStyle.cancel],
handlers: [nil], animated: false)
回答8:
You can use my Utility class created for Show Alert in Swift4. Its super easy to use just by writing single line of code:
Show Simple Alert
@IBAction func showDefaultAlert(_ sender: Any) {
Alert.showAlert(title:"Alert", message:"Default Alert")
}
Demo code link: https://github.com/smindia1988/EasyAlertInSwift4
回答9:
I am suggest you write this code, but if you really need, try this:
static func showAlertMessage(titleStr:String, messageStr:String) -> Void {
let alert = UIAlertController(title: titleStr, message: messageStr, preferredStyle: UIAlertControllerStyle.Alert);
if let viewController = UIApplication.sharedApplication().windows.first?.rootViewController as UIViewController? {
viewController.presentViewController(alert, animated: true, completion: nil)
}
}
At least it won't break down.
@Eric D better answer.
回答10:
If you want to present from AppDelegate windows you can use like this
UIApplication.sharedApplication().delegate?.window.rootViewController?.presentViewController(vc, animated: true, completion: nil)
回答11:
This is also the way you can present on top of the View Controller available.
UIApplication.topViewController()?.present(alertViewController!, animated: true, completion: nil)
