[002][iOS-Swift]使用UISwitch控制本地消息

（完整代码见文末）

屏幕快照 2019-06-18 下午12.56.39.png

在viewWillAppear 中调用checkNotification()，检查通知，并使 switch 的状态对应

    override func viewWillAppear(_ animated: Bool) {
        self.checkNotification()
    }
    
    @objc func checkNotification() {
        UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) { (accept, error) in
            if !accept {
                DispatchQueue.main.async {
                    self.notificationSwitch.isOn = false
                }
            } else {
                DispatchQueue.main.async {
                    self.notificationSwitch.isOn = true
                }
            }
        }
    }

屏幕快照 2019-06-18 下午12.56.51.png

如果当前 switch 是开着的，点击之后，立马变为关的状态，所以下面的判断是如果 switch 是关的状态时有个Alert提示框。

   @IBAction func switchNotification(_ sender: UISwitch) {
      
       if notificationSwitch.isOn == false {
           // 一个Alert提示框，用户点击确认之后再跳转到消息通知界面
           let alertController = UIAlertController(title: "温馨提示", message: "确认关闭消息通知？关闭消息通知将影响App的使用", preferredStyle: .alert)
           let cancelAction = UIAlertAction(title: "取消", style: .cancel) { (cancel) in
               self.notificationSwitch.isOn = !self.notificationSwitch.isOn
           }
           
           let confirmAction = UIAlertAction(title: "确认", style: .default) { (okaction) in
               // 跳转到消息通知界面
               let url = URL(string: UIApplication.openSettingsURLString)
               if let url = url, UIApplication.shared.canOpenURL(url) {
                   if #available(iOS 10, *) {
                       UIApplication.shared.open(url, options: [:], completionHandler: { (success) in
                       })
                   } else {
                       UIApplication.shared.openURL(url)
                   }
               }
               
           }
           alertController.addAction(cancelAction)
           alertController.addAction(confirmAction)
           self.present(alertController, animated: true, completion: nil)
       } else {
            // 直接转到开启通知界面
           let url = URL(string: UIApplication.openSettingsURLString)
           if let url = url, UIApplication.shared.canOpenURL(url) {
               if #available(iOS 10, *) {
                   UIApplication.shared.open(url, options: [:], completionHandler: { (success) in
                       
                   })
               } else {
                   UIApplication.shared.openURL(url)
               }
           }
       }
       
   }

屏幕快照 2019-06-18 下午12.57.05.png

跳转到系统设置的当前 testproject app设置之后，点击通知。

屏幕快照 2019-06-18 下午12.57.18.png

开启或者关闭通知之后，点击左上角返回到 testproject app。
由于从系统设置返回不会调用 vc 生命周期的方法， 在 viewDidLoad 以及 viewWillAppear 检查是否开启通知，更新 switch 的状态是无效的，所以添加一个 observer，当 app didBecomeActive时，再调用checkNotification()，刷新界面

   override func viewDidLoad() {
       super.viewDidLoad()
      
       NotificationCenter.default.addObserver(self, selector: #selector(checkNotification), name: UIApplication.didBecomeActiveNotification, object: nil)
   }

   @objc func checkNotification() {
       UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) { (accept, error) in
           if !accept {
               DispatchQueue.main.async {
                   self.notificationSwitch.isOn = false
               }
           } else {
               DispatchQueue.main.async {
                   self.notificationSwitch.isOn = true
               }
           }
       }
   }

---

完整代码

import UIKit
import UserNotifications

class NotificationViewController: UIViewController {

    @IBOutlet weak var notificationSwitch: UISwitch!
    
   
    override func viewDidLoad() {
        super.viewDidLoad()
       
        NotificationCenter.default.addObserver(self, selector: #selector(checkNotification), name: UIApplication.didBecomeActiveNotification, object: nil)
    }
    
    override func viewWillAppear(_ animated: Bool) {
        self.checkNotification()
    }
 
    @objc func checkNotification() {
        UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) { (accept, error) in
            if !accept {
                DispatchQueue.main.async {
                    self.notificationSwitch.isOn = false
                }
            } else {
                DispatchQueue.main.async {
                    self.notificationSwitch.isOn = true
                }
            }
        }
    }
    

    @IBAction func switchNotification(_ sender: UISwitch) {
       
        if notificationSwitch.isOn == false {
            // 一个Alert提示框，用户点击确认之后再跳转到消息通知界面
            let alertController = UIAlertController(title: "温馨提示", message: "确认关闭消息通知？关闭消息通知将影响App的使用", preferredStyle: .alert)
            let cancelAction = UIAlertAction(title: "取消", style: .cancel) { (cancel) in
                self.notificationSwitch.isOn = !self.notificationSwitch.isOn
            }
            
            let confirmAction = UIAlertAction(title: "确认", style: .default) { (okaction) in
                // 跳转到消息通知界面
                let url = URL(string: UIApplication.openSettingsURLString)
                if let url = url, UIApplication.shared.canOpenURL(url) {
                    if #available(iOS 10, *) {
                        UIApplication.shared.open(url, options: [:], completionHandler: { (success) in
                        })
                    } else {
                        UIApplication.shared.openURL(url)
                    }
                }
                
            }
            alertController.addAction(cancelAction)
            alertController.addAction(confirmAction)
            self.present(alertController, animated: true, completion: nil)
        } else {
             // 直接转到开启通知界面
            let url = URL(string: UIApplication.openSettingsURLString)
            if let url = url, UIApplication.shared.canOpenURL(url) {
                if #available(iOS 10, *) {
                    UIApplication.shared.open(url, options: [:], completionHandler: { (success) in
                        
                    })
                } else {
                    UIApplication.shared.openURL(url)
                }
            }
        }
        
    }

}

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