这个功能使用说明是每次app更新或者第一次安装都需要显示的。你可以给每个需要显示的说明界面设置一个BOOL变量控制它是否显示。在applicationDidFinishLaunching的函数中判断app是第一次安装还是更新升级。

NSString *appVersion = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleShortVersionString"];

NSString *appBuild = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"];

if (![NSUserDefaults stringForKey:@"appVersion"] ||

![NSUserDefaults stringForKey:@"appBuild"] ||

![[NSUserDefaults stringForKey:@"appVersion"] isEqualToString:appVersion] ||

![[NSUserDefaults stringForKey:@"appBuild"] isEqualToString:appBuild]) {

[NSUserDefaults setBool:YES forKey:isFirstLaunch];

[NSUserDefaults setString:appVersion forKey:@"appVersion"];

[NSUserDefaults setString:appBuild forKey:@"appBuild"];

}