How to check iOS version?

Question

I want to check if the iOS version of the device is greater than 3.1.3 I tried things like:

[[UIDevice currentDevice].systemVersion floatValue]

but it does not work, I just want a:

if (version > 3.1.3) { }

How can I achieve this?

Answer 1

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

Then add a if condition as follows:-

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

Answer 2

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
}

Answer 3

In general it's better to ask if an object can perform a given selector, rather than checking a version number to decide if it must be present.

When this is not an option, you do need to be a bit careful here because [@"5.0" compare:@"5" options:NSNumericSearch] returns NSOrderedDescending which might well not be intended at all; I might expect NSOrderedSame here. This is at least a theoretical concern, one that is worth defending against in my opinion.

Also worth considering is the possibility of a bad version input which can not reasonably be compared to. Apple supplies the three predefined constants NSOrderedAscending, NSOrderedSame and NSOrderedDescending but I can think of a use for some thing called NSOrderedUnordered in the event I can't compare two things and I want to return a value indicating this.

What's more, it's not impossible that Apple will some day expand their three predefined constants to allow a variety of return values, making a comparison != NSOrderedAscending unwise.

With this said, consider the following code.

typedef enum {kSKOrderedNotOrdered = -2, kSKOrderedAscending = -1, kSKOrderedSame = 0, kSKOrderedDescending = 1} SKComparisonResult;

@interface SKComparator : NSObject
+ (SKComparisonResult)comparePointSeparatedVersionNumber:(NSString *)vOne withPointSeparatedVersionNumber:(NSString *)vTwo;
@end

@implementation SKComparator
+ (SKComparisonResult)comparePointSeparatedVersionNumber:(NSString *)vOne withPointSeparatedVersionNumber:(NSString *)vTwo {
  if (!vOne || !vTwo || [vOne length] < 1 || [vTwo length] < 1 || [vOne rangeOfString:@".."].location != NSNotFound ||
    [vTwo rangeOfString:@".."].location != NSNotFound) {
    return SKOrderedNotOrdered;
  }
  NSCharacterSet *numericalCharSet = [NSCharacterSet characterSetWithCharactersInString:@".0123456789"];
  NSString *vOneTrimmed = [vOne stringByTrimmingCharactersInSet:numericalCharSet];
  NSString *vTwoTrimmed = [vTwo stringByTrimmingCharactersInSet:numericalCharSet];
  if ([vOneTrimmed length] > 0 || [vTwoTrimmed length] > 0) {
    return SKOrderedNotOrdered;
  }
  NSArray *vOneArray = [vOne componentsSeparatedByString:@"."];
  NSArray *vTwoArray = [vTwo componentsSeparatedByString:@"."];
  for (NSUInteger i = 0; i < MIN([vOneArray count], [vTwoArray count]); i++) {
    NSInteger vOneInt = [[vOneArray objectAtIndex:i] intValue];
    NSInteger vTwoInt = [[vTwoArray objectAtIndex:i] intValue];
    if (vOneInt > vTwoInt) {
      return kSKOrderedDescending;
    } else if (vOneInt < vTwoInt) {
      return kSKOrderedAscending;
    }
  }
  if ([vOneArray count] > [vTwoArray count]) {
    for (NSUInteger i = [vTwoArray count]; i < [vOneArray count]; i++) {
      if ([[vOneArray objectAtIndex:i] intValue] > 0) {
        return kSKOrderedDescending;
      }
    }
  } else if ([vOneArray count] < [vTwoArray count]) {
    for (NSUInteger i = [vOneArray count]; i < [vTwoArray count]; i++) {
      if ([[vTwoArray objectAtIndex:i] intValue] > 0) {
        return kSKOrderedAscending;
      }
    }
  }
  return kSKOrderedSame;
}
@end

Answer 4

Preferred Approach

In Swift 2.0 Apple added availability checking using a far more convenient syntax (Read more here). Now you can check the OS version with a cleaner syntax:

if #available(iOS 9, *) {
    // Then we are on iOS 9
} else {
    // iOS 8 or earlier
}

This is the preferred over checking respondsToSelector etc (What's New In Swift). Now the compiler will always warn you if you aren't guarding your code properly.

---

Pre Swift 2.0

New in iOS 8 is NSProcessInfo allowing for better semantic versioning checks.

Deploying on iOS 8 and greater

For minimum deployment targets of iOS 8.0 or above, use NSProcessInfo operatingSystemVersion or isOperatingSystemAtLeastVersion.

This would yield the following:

let minimumVersion = NSOperatingSystemVersion(majorVersion: 8, minorVersion: 1, patchVersion: 2)
if NSProcessInfo().isOperatingSystemAtLeastVersion(minimumVersion) {
    //current version is >= (8.1.2)
} else {
    //current version is < (8.1.2)
}

Deploying on iOS 7

For minimum deployment targets of iOS 7.1 or below, use compare with NSStringCompareOptions.NumericSearch on UIDevice systemVersion.

This would yield:

let minimumVersionString = "3.1.3"
let versionComparison = UIDevice.currentDevice().systemVersion.compare(minimumVersionString, options: .NumericSearch)
switch versionComparison {
    case .OrderedSame, .OrderedDescending:
        //current version is >= (3.1.3)
        break
    case .OrderedAscending:
        //current version is < (3.1.3)
        fallthrough
    default:
        break;
}

More reading at NSHipster.

Answer 5

A more generic version in Obj-C++ 11 (you could probably replace some of this stuff with the NSString/C functions, but this is less verbose. This gives you two mechanisms. splitSystemVersion gives you an array of all the parts which is useful if you just want to switch on the major version (e.g. switch([self splitSystemVersion][0]) {case 4: break; case 5: break; }).

#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;
}

Answer 6

Swift example that actually works:

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

Don't use NSProcessInfo cause it doesn't work under 8.0, so its pretty much useless until 2016