我也知道这个问题已经有了答案，但我总结了之前的答案:

(*)扩展更新

extension Bundle {
    var releaseVersionNumber: String? {
        return infoDictionary?["CFBundleShortVersionString"] as? String
    }
    var buildVersionNumber: String? {
        return infoDictionary?["CFBundleVersion"] as? String
    }
    var releaseVersionNumberPretty: String {
        return "v\(releaseVersionNumber ?? "1.0.0")"
    }
}

用法:

someLabel.text = Bundle.main.releaseVersionNumberPretty

@Deprecated:旧答案

斯威夫特3.1:

class func getVersion() -> String {
    guard let version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String else {
        return "no version info"
    }
    return version
}

对于旧版本:

class func getVersion() -> String {
    if let version = NSBundle.mainBundle().infoDictionary?["CFBundleShortVersionString"] as? String {
        return version
    }
    return "no version info"
}

如果你想设置标签文本或者想在其他地方使用;

self.labelVersion.text = getVersion()

2022年，Swift 5

extension Bundle {
    public var appName: String           { getInfo("CFBundleName")  }
    public var displayName: String       { getInfo("CFBundleDisplayName")}
    public var language: String          { getInfo("CFBundleDevelopmentRegion")}
    public var identifier: String        { getInfo("CFBundleIdentifier")}
    public var copyright: String         { getInfo("NSHumanReadableCopyright").replacingOccurrences(of: "\\\\n", with: "\n") }
    
    public var appBuild: String          { getInfo("CFBundleVersion") }
    public var appVersionLong: String    { getInfo("CFBundleShortVersionString") }
    //public var appVersionShort: String { getInfo("CFBundleShortVersion") }
    
    fileprivate func getInfo(_ str: String) -> String { infoDictionary?[str] as? String ?? "⚠️" }
}

用法(SwiftUI样本):

    Text("Ver: \(Bundle.main.appVersionLong) (\(Bundle.main.appBuild)) ")
    
    Text(Bundle.main.copyright)
        .font(.system(size: 10, weight: .thin))
        .multilineTextAlignment(.center)

奖励:版权支持\n符号!

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

斯威夫特3:

版本号

if let versionNumberString = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String { // do something }

建立数

if let buildNumberString = Bundle.main.infoDictionary?["CFBundleVersion"] as? String { // do something }

对于Swift 1.2，它是:

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

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