鉴于Swift一直在发展，我的回答(截至2015年8月):

let version = NSBundle.mainBundle().infoDictionary!["CFBundleVersion"] as! String

我为UIApplication创建了一个扩展。

extension UIApplication {
    static var appVersion: String {
        let versionNumber = Bundle.main.infoDictionary?[IdentifierConstants.InfoPlist.versionNumber] as? String
        let buildNumber = Bundle.main.infoDictionary?[IdentifierConstants.InfoPlist.buildNumber] as? String
        
        let formattedBuildNumber = buildNumber.map {
            return "(\($0))"
        }

        return [versionNumber,formattedBuildNumber].compactMap { $0 }.joined(separator: " ")
    }
}

enum Constants {
    enum InfoPlist {
        static let versionNumber = "CFBundleShortVersionString"
        static let buildNumber = "CFBundleVersion"
    }
}

针对Swift 3.0更新

在Swift 3.0中，ns前缀已经没有了，一些属性/方法的名称已经更改为更Swifty。这是现在的样子:

extension Bundle {
    var releaseVersionNumber: String? {
        return infoDictionary?["CFBundleShortVersionString"] as? String
    }
    var buildVersionNumber: String? {
        return infoDictionary?["CFBundleVersion"] as? String
    }
}

Bundle.main.releaseVersionNumber
Bundle.main.buildVersionNumber

更新答案

I've been working with Frameworks a lot since my original answer, so I wanted to update my solution to something that is both simpler and much more useful in a multi-bundle environment: extension NSBundle { var releaseVersionNumber: String? { return self.infoDictionary?["CFBundleShortVersionString"] as? String } var buildVersionNumber: String? { return self.infoDictionary?["CFBundleVersion"] as? String } } Now this extension will be useful in apps to identify both the main bundle and any other included bundles (such as a shared framework for extension programming or third frameworks like AFNetworking), like so: NSBundle.mainBundle().releaseVersionNumber NSBundle.mainBundle().buildVersionNumber // or... NSBundle(URL: someURL)?.releaseVersionNumber NSBundle(URL: someURL)?.buildVersionNumber

原来的答案

I wanted to improve on some of the answers already posted. I wrote a class extension that can be added to your tool chain to handle this in a more logical fashion. extension NSBundle { class var applicationVersionNumber: String { if let version = NSBundle.mainBundle().infoDictionary?["CFBundleShortVersionString"] as? String { return version } return "Version Number Not Available" } class var applicationBuildNumber: String { if let build = NSBundle.mainBundle().infoDictionary?["CFBundleVersion"] as? String { return build } return "Build Number Not Available" } } So now you can access this easily by: let versionNumber = NSBundle.applicationVersionNumber

斯威夫特4

//首先通过定义一个可选的AnyObject来获取nsObject

let nsObject: AnyObject? = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as AnyObject

//然后将对象转换为String，但要小心，你可能需要再次检查是否为nil

let version = nsObject as! String

Swift 5更新

这是一个函数，我使用来决定是否显示“应用程序更新”页面或不。它返回版本号，我正在将其转换为Int类型:

if let version: String = Bundle.main.infoDictionary?["CFBundleVersion"] as? String {
        guard let intVersion = Int(version) else { return }
        
        if UserDefaults.standard.integer(forKey: "lastVersion") < intVersion {
            print("need to show popup")
        } else {
            print("Don't need to show popup")
        }
        
        UserDefaults.standard.set(intVersion, forKey: "lastVersion")
    }

如果以前从未使用过，它将返回0，小于当前版本号。若要不向新用户显示这样的屏幕，只需在首次登录后或登录完成时添加构建号。

以下是Swift 3.2的更新版本:

extension UIApplication
{
    static var appVersion:String
    {
        if let appVersion = Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString")
        {
            return "\(appVersion)"
        }
        return ""
    }

    static var buildNumber:String
    {
        if let buildNum = Bundle.main.object(forInfoDictionaryKey: kCFBundleVersionKey as String)
        {
            return "\(buildNum)"
        }
        return ""
    }

    static var versionString:String
    {
        return "\(appVersion).\(buildNumber)"
    }
}