我想检查设备的iOS版本是否大于3.1.3 我尝试了以下方法:
[[UIDevice currentDevice].systemVersion floatValue]
但是不管用，我只想要一个:
if (version > 3.1.3) { }
我怎样才能做到这一点呢?
当前回答
这两种常见的答案存在一些问题:
Comparing strings using NSNumericSearch sometimes has unintuitive results (the SYSTEM_VERSION_* macros all suffer from this): [@"10.0" compare:@"10" options:NSNumericSearch] // returns NSOrderedDescending instead of NSOrderedSame FIX: Normalize your strings first and then perform the comparisons. could be annoying trying to get both strings in identical formats. Using the foundation framework version symbols is not possible when checking future releases NSFoundationVersionNumber_iOS_6_1 // does not exist in iOS 5 SDK FIX: Perform two separate tests to ensure the symbol exists AND THEN compare symbols. However another here: The foundation framwork versions symbols are not unique to iOS versions. Multiple iOS releases can have the same framework version. 9.2 & 9.3 are both 1242.12 8.3 & 8.4 are both 1144.17 FIX: I believe this issue is unresolvable
为了解决这些问题，下面的方法将版本号字符串处理为以10000为基数的数字(每个主要/次要/补丁组件都是一个单独的数字)，并执行以十进制为基数的转换，以便使用整数运算符进行比较。
添加了另外两个方法，用于方便地比较iOS版本字符串，以及比较字符串与任意数量的组件。
+ (SInt64)integerFromVersionString:(NSString *)versionString withComponentCount:(NSUInteger)componentCount
{
//
// performs base conversion from a version string to a decimal value. the version string is interpreted as
// a base-10000 number, where each component is an individual digit. this makes it simple to use integer
// operations for comparing versions. for example (with componentCount = 4):
//
// version "5.9.22.1" = 5*1000^3 + 9*1000^2 + 22*1000^1 + 1*1000^0 = 5000900220001
// and
// version "6.0.0.0" = 6*1000^3 + 0*1000^2 + 0*1000^1 + 0*1000^1 = 6000000000000
// and
// version "6" = 6*1000^3 + 0*1000^2 + 0*1000^1 + 0*1000^1 = 6000000000000
//
// then the integer comparisons hold true as you would expect:
//
// "5.9.22.1" < "6.0.0.0" // true
// "6.0.0.0" == "6" // true
//
static NSCharacterSet *nonDecimalDigitCharacter;
static dispatch_once_t onceToken;
dispatch_once(&onceToken,
^{ // don't allocate this charset every time the function is called
nonDecimalDigitCharacter = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
});
SInt64 base = 10000; // each component in the version string must be less than base
SInt64 result = 0;
SInt64 power = 0;
// construct the decimal value left-to-right from the version string
for (NSString *component in [versionString componentsSeparatedByString:@"."])
{
if (NSNotFound != [component rangeOfCharacterFromSet:nonDecimalDigitCharacter].location)
{
// one of the version components is not an integer, so bail out
result = -1;
break;
}
result += [component longLongValue] * (long long)pow((double)base, (double)(componentCount - ++power));
}
return result;
}
+ (SInt64)integerFromVersionString:(NSString *)versionString
{
return [[self class] integerFromVersionString:versionString
withComponentCount:[[versionString componentsSeparatedByString:@"."] count]];
}
+ (SInt64)integerFromiOSVersionString:(NSString *)versionString
{
// iOS uses 3-component version string
return [[self class] integerFromVersionString:versionString
withComponentCount:3];
}
它支持许多版本标识符(通过4位数字，0-9999;可以支持任意数量的组件(Apple目前似乎使用3个组件，例如major.minor.patch)，但这可以使用componentCount参数显式指定。确保你的componentCount和base不会导致溢出，即确保2^63 >= base^componentCount!
使用的例子:
NSString *currentVersion = [[UIDevice currentDevice] systemVersion];
if ([Util integerFromiOSVersionString:currentVersion] >= [Util integerFromiOSVersionString:@"42"])
{
NSLog(@"we are in some horrible distant future where iOS still exists");
}
其他回答
根据苹果官方文档的建议:你可以使用nsobjcrtime .h头文件中的NSFoundationVersionNumber。
if (floor(NSFoundationVersionNumber) > NSFoundationVersionNumber_iOS_6_1) {
// here you go with iOS 7
}
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")
这两种常见的答案存在一些问题:
Comparing strings using NSNumericSearch sometimes has unintuitive results (the SYSTEM_VERSION_* macros all suffer from this): [@"10.0" compare:@"10" options:NSNumericSearch] // returns NSOrderedDescending instead of NSOrderedSame FIX: Normalize your strings first and then perform the comparisons. could be annoying trying to get both strings in identical formats. Using the foundation framework version symbols is not possible when checking future releases NSFoundationVersionNumber_iOS_6_1 // does not exist in iOS 5 SDK FIX: Perform two separate tests to ensure the symbol exists AND THEN compare symbols. However another here: The foundation framwork versions symbols are not unique to iOS versions. Multiple iOS releases can have the same framework version. 9.2 & 9.3 are both 1242.12 8.3 & 8.4 are both 1144.17 FIX: I believe this issue is unresolvable
为了解决这些问题，下面的方法将版本号字符串处理为以10000为基数的数字(每个主要/次要/补丁组件都是一个单独的数字)，并执行以十进制为基数的转换，以便使用整数运算符进行比较。
添加了另外两个方法，用于方便地比较iOS版本字符串，以及比较字符串与任意数量的组件。
+ (SInt64)integerFromVersionString:(NSString *)versionString withComponentCount:(NSUInteger)componentCount
{
//
// performs base conversion from a version string to a decimal value. the version string is interpreted as
// a base-10000 number, where each component is an individual digit. this makes it simple to use integer
// operations for comparing versions. for example (with componentCount = 4):
//
// version "5.9.22.1" = 5*1000^3 + 9*1000^2 + 22*1000^1 + 1*1000^0 = 5000900220001
// and
// version "6.0.0.0" = 6*1000^3 + 0*1000^2 + 0*1000^1 + 0*1000^1 = 6000000000000
// and
// version "6" = 6*1000^3 + 0*1000^2 + 0*1000^1 + 0*1000^1 = 6000000000000
//
// then the integer comparisons hold true as you would expect:
//
// "5.9.22.1" < "6.0.0.0" // true
// "6.0.0.0" == "6" // true
//
static NSCharacterSet *nonDecimalDigitCharacter;
static dispatch_once_t onceToken;
dispatch_once(&onceToken,
^{ // don't allocate this charset every time the function is called
nonDecimalDigitCharacter = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
});
SInt64 base = 10000; // each component in the version string must be less than base
SInt64 result = 0;
SInt64 power = 0;
// construct the decimal value left-to-right from the version string
for (NSString *component in [versionString componentsSeparatedByString:@"."])
{
if (NSNotFound != [component rangeOfCharacterFromSet:nonDecimalDigitCharacter].location)
{
// one of the version components is not an integer, so bail out
result = -1;
break;
}
result += [component longLongValue] * (long long)pow((double)base, (double)(componentCount - ++power));
}
return result;
}
+ (SInt64)integerFromVersionString:(NSString *)versionString
{
return [[self class] integerFromVersionString:versionString
withComponentCount:[[versionString componentsSeparatedByString:@"."] count]];
}
+ (SInt64)integerFromiOSVersionString:(NSString *)versionString
{
// iOS uses 3-component version string
return [[self class] integerFromVersionString:versionString
withComponentCount:3];
}
它支持许多版本标识符(通过4位数字，0-9999;可以支持任意数量的组件(Apple目前似乎使用3个组件，例如major.minor.patch)，但这可以使用componentCount参数显式指定。确保你的componentCount和base不会导致溢出，即确保2^63 >= base^componentCount!
使用的例子:
NSString *currentVersion = [[UIDevice currentDevice] systemVersion];
if ([Util integerFromiOSVersionString:currentVersion] >= [Util integerFromiOSVersionString:@"42"])
{
NSLog(@"we are in some horrible distant future where iOS still exists");
}
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
}
在主界面轻按“设置”>常规>关于。 设备的软件版本应该出现在这个屏幕上。 检查版本号是否大于3.1.3。
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