Swift 4，有用的扩展包

import Foundation

public extension Bundle {

    public var shortVersion: String {
        if let result = infoDictionary?["CFBundleShortVersionString"] as? String {
            return result
        } else {
            assert(false)
            return ""
        }
    }

    public var buildVersion: String {
        if let result = infoDictionary?["CFBundleVersion"] as? String {
            return result
        } else {
            assert(false)
            return ""
        }
    }

    public var fullVersion: String {
        return "\(shortVersion)(\(buildVersion))"
    }
}

看过文档后，我认为以下内容更清晰:

let version = 
NSBundle.mainBundle().objectForInfoDictionaryKey("CFBundleShortVersionString") 
as? String

来源: 使用此方法优于其他访问方法，因为它在键可用时返回键的本地化值。

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"
    }
}

对于Swift 3.0 NSBundle不工作，下面的代码工作完美。

let versionNumberString =
      Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString")
          as! String

对于版本号，它是:

let buildNumberString =
      Bundle.main.object(forInfoDictionaryKey: "CFBundleVersion")
          as! String

令人困惑的'CFBundleVersion'是在Xcode General->Identity中输入的构建号。

现在您可以使用常量来实现这一点，而不必像以前那样使用字符串类型的代码，这使得事情变得更加方便。

var appVersion: String {
    return Bundle.main.infoDictionary![kCFBundleVersionKey as String] as! String
}

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()