掛機退出應用程序並顯示警報

Question

我需要在用戶通過單擊x按鈕退出應用程序時顯示警告框。如何掛接應用程序的退出事件並顯示警報或視圖通過賽格瑞

performSegue(withIdentifier: "segue", sender: nil) 

請諮詢控制器..

Answer 1

在你的appdelegate你應該能夠把你的代碼放到applicationWillTerminate，使消息出現在那裏。

編輯：你可能會更好使用模態警報，而不是一個segue。

Answer 2

我知道你想用segue來做到這一點，因爲它們只是非常方便，但是在應用程序委託事件（如「applicationWillResignActive」（前往後臺）或「applicationWillBecomeActive」 「（再次成爲前景）。

正確的做法是通過警報。你可能想在applicationShouldTerminate中這樣做，因爲你可能想要A）如果你有一個很好的理由不放棄，或者B）給用戶一個選擇是否真的退出。

下面是它會怎樣看在SWIFT 4：

var licenseWindowController : LicenseWindowController? 

func dialogOKCancel(question: String, text: String) -> Bool { 
    let alert = NSAlert() 
    alert.messageText = question 
    alert.informativeText = text 
    alert.alertStyle = .warning 
    alert.addButton(withTitle: "OK") 
    alert.addButton(withTitle: "Cancel") 
    return alert.runModal() == .alertFirstButtonReturn 
} 

func applicationShouldTerminate(_ sender: NSApplication) -> NSApplication.TerminateReply { 

    let answer = dialogOKCancel(question: "Ok?", text: "Should we really quit?") 
    if answer == true 
    { 
     return .terminateNow 
    } else { 

func applicationShouldTerminate(_ sender: NSApplication) -> NSApplication.TerminateReply { 

    let answer = dialogOKCancel(question: "Ok?", text: "Should we really quit?") 
    if answer == true 
    { 

     return .terminateNow 

    } else { 

     // to bring up a window from your storyboard... 
     let mainStoryboard = NSStoryboard.init(name: NSStoryboard.Name(rawValue: "Main"), bundle: nil) 
     self.licenseWindowController = mainStoryboard.instantiateController(withIdentifier: NSStoryboard.SceneIdentifier(rawValue: "LicenseWindowController")) as? LicenseWindowController 
     if let actualLicenseWC = self.licenseWindowController 
     { 
      actualLicenseWC.showWindow(self) 
     } 

     return .terminateCancel 
    } 
} 

斯威夫特3

var licenseWindowController : LicenseWindowController? 

func dialogOKCancel(question: String, text: String) -> Bool { 
    let alert = NSAlert() 
    alert.messageText = question 
    alert.informativeText = text 
    alert.alertStyle = .warning 
    alert.addButton(withTitle: "OK") 
    alert.addButton(withTitle: "Cancel") 
    return alert.runModal() == NSAlertFirstButtonReturn 
} 

func applicationShouldTerminate(_ sender: NSApplication) -> NSApplicationTerminateReply { 

    let answer = dialogOKCancel(question: "Ok?", text: "Should we really quit?") 
    if answer == true 
    { 
     return .terminateNow 
    } else { 
     let mainStoryboard = NSStoryboard.init(name: "Main", bundle: nil) 
     self.licenseWindowController = mainStoryboard.instantiateController(withIdentifier: "LicenseWindowController") as? LicenseWindowController 
     if let actualLicenseWC = self.licenseWindowController 
     { 
      actualLicenseWC.showWindow(self) 
     } 

     return .terminateCancel 
    } 
}