我知道这个问题已经有人回答了，但我个人认为这个问题更清晰一些:

斯威夫特3.0:

 if let version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String {
    self.labelVersion.text = version
}

斯威夫特< 2.3

if let version = NSBundle.mainBundle().infoDictionary?["CFBundleShortVersionString"] as? String {
    self.labelVersion.text = version
}

这样，if let版本就负责条件处理(在我的例子中设置标签文本)，如果infoDictionary或CFBundleShortVersionString为nil，则可选的展开将导致代码被跳过。

针对Swift 4.0

let version = Bundle.main.infoDictionary!["CFBundleShortVersionString"]!
let build = Bundle.main.infoDictionary!["CFBundleVersion"]!

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 }

捆绑+扩展.swift

import Foundation

extension Bundle {
    var versionNumber: String? {
        return infoDictionary?["CFBundleShortVersionString"] as? String
    }

    var buildNumber: String? {
        return infoDictionary?["CFBundleVersion"] as? String
    }

    var bundleName: String? {
        return infoDictionary?["CFBundleName"] as? String
    }
}

用法:

someLabel.text = Bundle.main.versionNumber

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))"
    }
}

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()