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
 }

#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
}       

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
}

基本上和这个想法一样https://stackoverflow.com/a/19903595/1937908但更健壮:

#ifndef func_i_system_version_field
#define func_i_system_version_field

inline static int i_system_version_field(unsigned int fieldIndex) {
  NSString* const versionString = UIDevice.currentDevice.systemVersion;
  NSArray<NSString*>* const versionFields = [versionString componentsSeparatedByString:@"."];
  if (fieldIndex < versionFields.count) {
    NSString* const field = versionFields[fieldIndex];
    return field.intValue;
  }
  NSLog(@"[WARNING] i_system_version(%iu): field index not present in version string '%@'.", fieldIndex, versionString);
  return -1; // error indicator
}

#endif

只需将上面的代码放在一个头文件中。

用法:

int major = i_system_version_field(0);
int minor = i_system_version_field(1);
int patch = i_system_version_field(2);

一个在obj - c++ 11中更通用的版本(你可能会用NSString/C函数替换其中的一些东西，但这不是那么冗长。这给了你两种机制。splitSystemVersion为你提供了一个包含所有部分的数组，如果你只是想打开主版本(例如switch([self splitSystemVersion][0]) {case 4: break;案例5:断裂;})。

#include <boost/lexical_cast.hpp>

- (std::vector<int>) splitSystemVersion {
    std::string version = [[[UIDevice currentDevice] systemVersion] UTF8String];
    std::vector<int> versions;
    auto i = version.begin();

    while (i != version.end()) {
        auto nextIllegalChar = std::find_if(i, version.end(), [] (char c) -> bool { return !isdigit(c); } );
        std::string versionPart(i, nextIllegalChar);
        i = std::find_if(nextIllegalChar, version.end(), isdigit);

        versions.push_back(boost::lexical_cast<int>(versionPart));
    }

    return versions;
}

/** Losslessly parse system version into a number
 * @return <0>: the version as a number,
 * @return <1>: how many numeric parts went into the composed number. e.g.
 * X.Y.Z = 3.  You need this to know how to compare again <0>
 */
- (std::tuple<int, int>) parseSystemVersion {
    std::string version = [[[UIDevice currentDevice] systemVersion] UTF8String];
    int versionAsNumber = 0;
    int nParts = 0;

    auto i = version.begin();
    while (i != version.end()) {
        auto nextIllegalChar = std::find_if(i, version.end(), [] (char c) -> bool { return !isdigit(c); } );
        std::string versionPart(i, nextIllegalChar);
        i = std::find_if(nextIllegalChar, version.end(), isdigit);

        int part = (boost::lexical_cast<int>(versionPart));
        versionAsNumber = versionAsNumber * 100 + part;
        nParts ++;
    }

    return {versionAsNumber, nParts};
}


/** Assume that the system version will not go beyond X.Y.Z.W format.
 * @return The version string.
 */
- (int) parseSystemVersionAlt {
    std::string version = [[[UIDevice currentDevice] systemVersion] UTF8String];
    int versionAsNumber = 0;
    int nParts = 0;

    auto i = version.begin();
    while (i != version.end() && nParts < 4) {
        auto nextIllegalChar = std::find_if(i, version.end(), [] (char c) -> bool { return !isdigit(c); } );
        std::string versionPart(i, nextIllegalChar);
        i = std::find_if(nextIllegalChar, version.end(), isdigit);

        int part = (boost::lexical_cast<int>(versionPart));
        versionAsNumber = versionAsNumber * 100 + part;
        nParts ++;
    }

    // don't forget to pad as systemVersion may have less parts (i.e. X.Y).
    for (; nParts < 4; nParts++) {
        versionAsNumber *= 100;
    }

    return versionAsNumber;
}