Question

我想使用以下代码，但仅适用于在iOS＆lt; 9.特别是我想在iOS8的设备上运行它。

#if __IPHONE_OS_VERSION_MAX_ALLOWED < 90000

-(UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window
{

    NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
    if(..)
      test()

    return UIInterfaceOrientationMaskPortrait | UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight;

}

#endif

但是，当我构建代码并在设备上运行时，该方法不会执行。我做错了什么？该应用程序具有最低iOS支持7.0，并且也可以在iOS9中运行（最新的xcode 7）

Answer 1

您需要删除#if __IPHONE_OS_VERSION_MAX_ALLOWED < 90000和#endif然后我认为这样做：

float version = [[[UIDevice currentDevice] systemVersion] floatValue];
if (version < 9.0f)
    test()

Answer 2

使用此＆＃34;系统版本控制预处理器宏＆＃34;用于检查系统版本

#define SYSTEM_VERSION_EQUAL_TO(v)                  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedSame)
#define SYSTEM_VERSION_GREATER_THAN(v)              ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedDescending)
#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN(v)                 ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN_OR_EQUAL_TO(v)     ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedDescending)

iOS的条件添加代码取决于设备iOS

2 个答案: