获取系统的当前版本并拆分它。 所以你可以得到大调和小调版本。

let sys_version = UIDevice.current.systemVersion
let all_version = sys_version.components(separatedBy: ".")
print("Major version : \(all_version[0])")
print("Minor version : \(all_version[1])")

获取系统的当前版本并拆分它。 所以你可以得到大调和小调版本。

let sys_version = UIDevice.current.systemVersion
let all_version = sys_version.components(separatedBy: ".")
print("Major version : \(all_version[0])")
print("Minor version : \(all_version[1])")

快4.倍

func iOS_VERSION_EQUAL_TO(version: String) -> Bool {
    return UIDevice.current.systemVersion.compare(version, options: NSString.CompareOptions.numeric) == ComparisonResult.orderedSame
}

func iOS_VERSION_GREATER_THAN(version: String) -> Bool {
    return UIDevice.current.systemVersion.compare(version, options: NSString.CompareOptions.numeric) == ComparisonResult.orderedDescending
}

func iOS_VERSION_GREATER_THAN_OR_EQUAL_TO(version: String) -> Bool {
    return UIDevice.current.systemVersion.compare(version, options: NSString.CompareOptions.numeric) != ComparisonResult.orderedAscending
}

func iOS_VERSION_LESS_THAN(version: String) -> Bool {
    return UIDevice.current.systemVersion.compare(version, options: NSString.CompareOptions.numeric) == ComparisonResult.orderedAscending
}

func iOS_VERSION_LESS_THAN_OR_EQUAL_TO(version: String) -> Bool {
    return UIDevice.current.systemVersion.compare(version, options: NSString.CompareOptions.numeric) != ComparisonResult.orderedDescending
}

用法:

if iOS_VERSION_GREATER_THAN_OR_EQUAL_TO(version: "11.0") {
    //Do something!
}

附:KVISH回答翻译成Swift 4。x和重命名函数，因为我专门为iOS应用程序使用这个片段。

斯威夫特5

我们不需要创建扩展，因为ProcessInfo给了我们版本信息。你可以在下面看到iOS的示例代码。

let os = ProcessInfo().operatingSystemVersion

switch (os.majorVersion, os.minorVersion, os.patchVersion) {
case (let x, _, _) where x < 8:
    print("iOS < 8.0.0")

case (8, 0, _):
    print("iOS >= 8.0.0, < 8.1.0")

case (8, _, _):
    print("iOS >= 8.1.0, < 9.0")

case (9, _, _):
    print("iOS >= 9.0.0")

default:
    print("iOS >= 10.0.0")
}

参考:http://nshipster.com/swift-system-version-checking/

在Swift 2及更高版本中，检查系统版本(以及许多其他版本)最简单和最简单的方法是:

if #available(iOS 9.0, *) { // check for iOS 9.0 and later

}

此外，使用#available你可以检查这些版本:

iOS
iOSApplicationExtension
macOS
macOSApplicationExtension
watchOS
watchOSApplicationExtension
tvOS
tvOSApplicationExtension
swift

let osVersion = NSProcessInfo.processInfo().operatingSystemVersion
let versionString = osVersion.majorVersion.description + "." + osVersion.minorVersion.description + "." + osVersion.patchVersion.description
print(versionString)