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
 }

我的解决方案是向您的实用程序类(提示提示)添加一个实用程序方法来解析系统版本并手动补偿浮点数排序。

此外，这段代码相当简单，所以我希望它能帮助一些新手。简单地传入一个目标浮点数，然后返回BOOL类型。

在你的共享类中这样声明它:

(+) (BOOL) iOSMeetsOrExceedsVersion:(float)targetVersion;

这样叫它:

BOOL shouldBranch = [SharedClass iOSMeetsOrExceedsVersion:5.0101];

(+) (BOOL) iOSMeetsOrExceedsVersion:(float)targetVersion {

/*
 Note: the incoming targetVersion should use 2 digits for each subVersion --

 example 5.01 for v5.1, 5.11 for v5.11 (aka subversions above 9), 5.0101 for v5.1.1, etc.
*/

// Logic: as a string, system version may have more than 2 segments (example: 5.1.1)
// so, a direct conversion to a float may return an invalid number
// instead, parse each part directly

NSArray *sysVersion = [[UIDevice currentDevice].systemVersion componentsSeparatedByString:@"."];
float floatVersion = [[sysVersion objectAtIndex:0] floatValue];
if (sysVersion.count > 1) {
    NSString* subVersion = [sysVersion objectAtIndex:1];
    if (subVersion.length == 1)
        floatVersion += ([[sysVersion objectAtIndex:1] floatValue] *0.01);
    else
        floatVersion += ([[sysVersion objectAtIndex:1] floatValue] *0.10);
}
if (sysVersion.count > 2) {
    NSString* subVersion = [sysVersion objectAtIndex:2];
    if (subVersion.length == 1)
        floatVersion += ([[sysVersion objectAtIndex:2] floatValue] *0.0001);
    else
        floatVersion += ([[sysVersion objectAtIndex:2] floatValue] *0.0010);
}

if (floatVersion  >= targetVersion) 
    return TRUE;

// else
return FALSE;
 }

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
}

使用推荐的方法…如果头文件中没有定义，你总是可以在控制台上用所需的IOS设备versión打印versión。

- (BOOL) isIOS8OrAbove{
    float version802 = 1140.109985;
    float version8= 1139.100000; // there is no def like NSFoundationVersionNumber_iOS_7_1 for ios 8 yet?
    NSLog(@"la version actual es [%f]", NSFoundationVersionNumber);
    if (NSFoundationVersionNumber >= version8){
        return true;
    }
    return false;
}

使用nv-ios-version项目(Apache License, Version 2.0)中包含的Version类，很容易获取和比较iOS版本。下面的示例代码转储iOS版本，并检查版本是否大于或等于6.0。

// Get the system version of iOS at runtime.
NSString *versionString = [[UIDevice currentDevice] systemVersion];

// Convert the version string to a Version instance.
Version *version = [Version versionWithString:versionString];

// Dump the major, minor and micro version numbers.
NSLog(@"version = [%d, %d, %d]",
    version.major, version.minor, version.micro);

// Check whether the version is greater than or equal to 6.0.
if ([version isGreaterThanOrEqualToMajor:6 minor:0])
{
    // The iOS version is greater than or equal to 6.0.
}

// Another way to check whether iOS version is
// greater than or equal to 6.0.
if (6 <= version.major)
{
    // The iOS version is greater than or equal to 6.0.
}

项目页面:nv-ios-version TakahikoKawasaki / nv-ios-version

博客:获取并比较iOS版本在运行时与版本类 获取并比较iOS版本在运行时与版本类

快速的例子，实际工作:

switch UIDevice.currentDevice().systemVersion.compare("8.0.0", options: NSStringCompareOptions.NumericSearch) {
case .OrderedSame, .OrderedDescending:
    println("iOS >= 8.0")
case .OrderedAscending:
    println("iOS < 8.0")
}

不要使用NSProcessInfo，因为它在8.0下不能工作，所以它在2016年之前几乎没用