使用 Swift 创建 NSAlert答案

【问题标题】：Create an NSAlert with Swift使用 Swift 创建 NSAlert
【发布时间】：2015-06-08 14:53:12
【问题描述】：

我有在 Objective-C 中创建和 NSAlert 的代码，但我现在想在 Swift 中创建它。

警报是为了确认用户想要删除文档。

我希望“删除”按钮运行删除功能，而“取消”按钮只是为了解除警报。

我怎样才能用 Swift 写这个？

NSAlert *alert = [[[NSAlert alloc] init] autorelease];
[alert addButtonWithTitle:@"Delete"];
[alert addButtonWithTitle:@"Cancel"];
[alert setMessageText:@"Delete the document?"];
[alert setInformativeText:@"Are you sure you would like to delete the document?"];
[alert setAlertStyle:NSWarningAlertStyle];
[alert beginSheetModalForWindow:[self window] modalDelegate:self didEndSelector:@selector(alertDidEnd:returnCode:contextInfo:) contextInfo:nil];

【问题讨论】：

您可能想考虑beginSheetModal(for:completionHandler:) 不已被弃用，实际上它可能是处理模态对话框（在一个块中）的更理想的方式。它也更接近于 didEndSelector 的旧方式，并且不会停止整个应用程序。

标签： swift cocoa nsalert

【解决方案1】：

beginSheetModalForWindow:modalDelegate 在 OS X 10.10 Yosemite 中已弃用。

斯威夫特 2

func dialogOKCancel(question: String, text: String) -> Bool {
    let alert: NSAlert = NSAlert()
    alert.messageText = question
    alert.informativeText = text
    alert.alertStyle = NSAlertStyle.WarningAlertStyle
    alert.addButtonWithTitle("OK")
    alert.addButtonWithTitle("Cancel")
    let res = alert.runModal()
    if res == NSAlertFirstButtonReturn {
        return true
    }
    return false
}

let answer = dialogOKCancel("Ok?", text: "Choose your answer.")

这将根据用户的选择返回true 或false。

NSAlertFirstButtonReturn 代表添加到对话框的第一个按钮，这里是“确定”按钮。

斯威夫特 3

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

let answer = dialogOKCancel(question: "Ok?", text: "Choose your answer.")

斯威夫特 4

我们现在使用枚举作为警报的样式和按钮选择。

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
}

let answer = dialogOKCancel(question: "Ok?", text: "Choose your answer.")

【讨论】：

确保import AppKit（至少在swift 3中）
@Claude 如果您发出警报，则意味着您正在制作一个 Cocoa 应用程序，这意味着您正在导入已经导入 AppKit 的 Cocoa。
可能我不应该从非 VC 类触发警报；但我只是想要一些穷人的错误显示。这个 util 类除了 Foundation 没有导入任何东西，所以我需要导入（至少它让 XCode 高兴）。
@Claude 哦，我明白了。在这种情况下，您手动导入 AppKit 是正确的 - 很抱歉造成混淆。
alert.alertStyle = .warning 也适用于 Swift 3，无需添加 NSAlertStyle

【解决方案2】：

我认为这可能对你有用...

let a = NSAlert()
a.messageText = "Delete the document?"
a.informativeText = "Are you sure you would like to delete the document?"
a.addButtonWithTitle("Delete")
a.addButtonWithTitle("Cancel")
a.alertStyle = NSAlert.Style.WarningAlertStyle

a.beginSheetModalForWindow(self.view.window!, completionHandler: { (modalResponse) -> Void in
    if modalResponse == NSAlertFirstButtonReturn {
        print("Document deleted")
    }
})

【讨论】：

NSAlert.Style.WarningAlertStyle 你需要在NSAlert 和Style 之间有一个句点

【解决方案3】：

更新了 Jose Hidalgo 对 Swift 4 的回答：

let a: NSAlert = NSAlert()
a.messageText = "Delete the document?"
a.informativeText = "Are you sure you would like to delete the document?"
a.addButton(withTitle: "Delete")
a.addButton(withTitle: "Cancel")
a.alertStyle = NSAlert.Style.warning

a.beginSheetModal(for: self.window!, completionHandler: { (modalResponse: NSApplication.ModalResponse) -> Void in
    if(modalResponse == NSApplication.ModalResponse.alertFirstButtonReturn){
        print("Document deleted")
    }
})

【讨论】：

【解决方案4】：

选择@Jose Hidalgo 对 Swift 5 的回答

        let a = NSAlert()
        a.messageText = "Delete the document?"
        a.informativeText = "Are you sure you would like to delete the document?"
        //   .alertFirstButtonReturn
        a.addButton(withTitle: "Delete")

        //   .alertSecondButtonReturn
        a.addButton(withTitle: "Cancel")
        a.alertStyle = .warning
        var w: NSWindow?
        if let window = view.window{
            w = window
        }
        else if let window = NSApplication.shared.windows.first{
            w = window
        }
        if let window = w{
            a.beginSheetModal(for: window){ (modalResponse) in
                if modalResponse == .alertFirstButtonReturn {
                    print("Document deleted")
                }
            }
        }

【讨论】：

在这里使用 nil 合并运算符会更漂亮，如下所示： if let window = view.window ?? NSApplication.shared.windows.first { alert.beginSheetModal(for: window) }
视图未定义？
是的，代码在NSViewController

【解决方案5】：

我尝试了上述解决方案，但无法获得适当大小的警报。我也定义了警报的大小。

        let alert = NSAlert()
        alert.messageText = "YOUR MESSAGE"
        alert.addButton(withTitle: "BUTTON1")
        alert.addButton(withTitle: "BUTTON2")
        var frame = alert.window.frame
        frame.size.height = 300
        frame.size.width = 200
        alert.window.setFrame(frame, display: true)
        
        let stackViewer = NSStackView(frame: NSRect(x: 0, y: 0, width: 200, height: 00))
        alert.accessoryView = stackViewer
        
        
        alert.beginSheetModal(for: self.view.window!, completionHandler: { (modalResponse) -> Void in
                if modalResponse == NSApplication.ModalResponse.alertFirstButtonReturn {
                    print("first btn")
                    
                }else{
                    print("second btn")
              
            }
        })

【讨论】：