#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)

然后添加if条件，如下所示:-

if(SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"10.0")) {
   //Your code
}       

UIDevice + IOSVersion.h

@interface UIDevice (IOSVersion)

+ (BOOL)isCurrentIOSVersionEqualToVersion:(NSString *)iOSVersion;
+ (BOOL)isCurrentIOSVersionGreaterThanVersion:(NSString *)iOSVersion;
+ (BOOL)isCurrentIOSVersionGreaterThanOrEqualToVersion:(NSString *)iOSVersion;
+ (BOOL)isCurrentIOSVersionLessThanVersion:(NSString *)iOSVersion;
+ (BOOL)isCurrentIOSVersionLessThanOrEqualToVersion:(NSString *)iOSVersion

@end

UIDevice + IOSVersion.m

#import "UIDevice+IOSVersion.h"

@implementation UIDevice (IOSVersion)

+ (BOOL)isCurrentIOSVersionEqualToVersion:(NSString *)iOSVersion
{
    return [[[UIDevice currentDevice] systemVersion] compare:iOSVersion options:NSNumericSearch] == NSOrderedSame;
}

+ (BOOL)isCurrentIOSVersionGreaterThanVersion:(NSString *)iOSVersion
{
    return [[[UIDevice currentDevice] systemVersion] compare:iOSVersion options:NSNumericSearch] == NSOrderedDescending;
}

+ (BOOL)isCurrentIOSVersionGreaterThanOrEqualToVersion:(NSString *)iOSVersion
{
    return [[[UIDevice currentDevice] systemVersion] compare:iOSVersion options:NSNumericSearch] != NSOrderedAscending;
}

+ (BOOL)isCurrentIOSVersionLessThanVersion:(NSString *)iOSVersion
{
    return [[[UIDevice currentDevice] systemVersion] compare:iOSVersion options:NSNumericSearch] == NSOrderedAscending;
}

+ (BOOL)isCurrentIOSVersionLessThanOrEqualToVersion:(NSString *)iOSVersion
{
    return [[[UIDevice currentDevice] systemVersion] compare:iOSVersion options:NSNumericSearch] != NSOrderedDescending;
}

@end

简单的回答是……

从Swift 2.0开始，你可以在if或guard中使用#available来保护那些只能在特定系统上运行的代码。

if #available(iOS 9， *) {} 在Objective-C中，您需要检查系统版本并进行比较。

iOS 8及以上版本[[NSProcessInfo processInfo] operatingSystemVersion]。

从Xcode 9开始:

if （@available（iOS 9， *）） {}

完整的答案是……

在Objective-C和Swift中，最好避免依赖操作系统版本作为设备或操作系统功能的指示。通常有更可靠的方法来检查特定的特性或类是否可用。

检查api的存在:

例如，你可以使用NSClassFromString检查UIPopoverController在当前设备上是否可用:

if (NSClassFromString(@"UIPopoverController")) {
    // Do something
}

对于弱链接的类，直接向类发送消息是安全的。值得注意的是，这适用于没有显式链接为“Required”的框架。对于缺少的类，表达式的计算结果为nil，不满足条件:

if ([LAContext class]) {
    // Do something
}

一些类，如CLLocationManager和UIDevice，提供了检查设备功能的方法:

if ([CLLocationManager headingAvailable]) {
    // Do something
}

检查符号的存在:

偶尔，您必须检查是否存在常数。这是在iOS 8中引入的UIApplicationOpenSettingsURLString，用于通过-openURL:加载设置应用程序。该值在iOS 8之前不存在。将nil传递给这个API会崩溃，所以你必须先注意验证这个常量的存在:

if (&UIApplicationOpenSettingsURLString != NULL) {
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];
}

与操作系统版本比较:

让我们假设您需要检查操作系统版本，这种情况相对较少。对于针对iOS 8及以上版本的项目，NSProcessInfo包含了一个执行版本比较的方法，出错的几率更小:

- (BOOL)isOperatingSystemAtLeastVersion:(NSOperatingSystemVersion)version

针对旧系统的项目可以在UIDevice上使用systemVersion。苹果在他们的GLSprite示例代码中使用了它。

// A system version of 3.1 or greater is required to use CADisplayLink. The NSTimer
// class is used as fallback when it isn't available.
NSString *reqSysVer = @"3.1";
NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
if ([currSysVer compare:reqSysVer options:NSNumericSearch] != NSOrderedAscending) {
    displayLinkSupported = TRUE;
}

如果出于某种原因，您决定systemVersion是您想要的，请确保将其视为字符串，否则您将冒着截断补丁版本号的风险(例如。3.1.2 -> 3.1)。

这是一个Swift版本的yasirmturk宏。希望它能帮助一些人

// MARK: System versionning

func SYSTEM_VERSION_EQUAL_TO(v: String) -> Bool {
    return UIDevice.currentDevice().systemVersion.compare(v, options: NSStringCompareOptions.NumericSearch) == NSComparisonResult.OrderedSame
}

func SYSTEM_VERSION_GREATER_THAN(v: String) -> Bool {
    return UIDevice.currentDevice().systemVersion.compare(v, options: NSStringCompareOptions.NumericSearch) == NSComparisonResult.OrderedDescending
}

func SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v: String) -> Bool {
    return UIDevice.currentDevice().systemVersion.compare(v, options: NSStringCompareOptions.NumericSearch) != NSComparisonResult.OrderedAscending
}

func SYSTEM_VERSION_LESS_THAN(v: String) -> Bool {
    return UIDevice.currentDevice().systemVersion.compare(v, options: NSStringCompareOptions.NumericSearch) == NSComparisonResult.OrderedAscending
}

func SYSTEM_VERSION_LESS_THAN_OR_EQUAL_TO(v: String) -> Bool {
    return UIDevice.currentDevice().systemVersion.compare(v, options: NSStringCompareOptions.NumericSearch) != NSComparisonResult.OrderedDescending
}

let kIsIOS7: Bool = SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO("7")
let kIsIOS7_1: Bool = SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO("7.1")
let kIsIOS8: Bool = SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO("8")
let kIsIOS9: Bool = SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO("9")

Try:

NSComparisonResult order = [[UIDevice currentDevice].systemVersion compare: @"3.1.3" options: NSNumericSearch];
if (order == NSOrderedSame || order == NSOrderedDescending) {
    // OS version >= 3.1.3
} else {
    // OS version < 3.1.3
}

有7.0或6.0.3这样的版本，所以我们可以简单地将版本转换为数字进行比较。如果版本类似于7.0，只需追加另一个”。0”，然后取它的数值。

 int version;
 NSString* iosVersion=[[UIDevice currentDevice] systemVersion];
 NSArray* components=[iosVersion componentsSeparatedByString:@"."];
 if ([components count]==2) {
    iosVersion=[NSString stringWithFormat:@"%@.0",iosVersion];

 }
 iosVersion=[iosVersion stringByReplacingOccurrencesOfString:@"." withString:@""];
 version=[iosVersion integerValue];

为0

  if (version==600) {
    // Do something
  }

为7.0

 if (version==700) {
   // Do something
 }