我們都知道如何用 Objective-C 創(chuàng)建 NSAlert：

    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];

假設(shè) alert 用于確認(rèn)用戶是否想刪除某個(gè)文檔。

我們希望“刪除”按鈕運(yùn)行刪除函數(shù)，“取消”按鈕只需隱藏 alert 即可。

但如何用 Swift 實(shí)現(xiàn)呢？

從 OS X 10.10 Yosemite 版本開始 beginSheetModalForWindow:modalDelegate 就已經(jīng)被棄用了

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

let answer = dialogOKCancel(question: "確認(rèn)？", text: "請(qǐng)選擇。")

該方法根據(jù)用的選擇返回 true 或 false。

NSAlertFirstButtonReturn 表示添加進(jìn) alert 的第一個(gè)按鈕，這里就是“好的”。