Judging the software is not the first time to start

In the opening of a software we have a simple Guide page or Welcome interface, guide page can help users clearly understand the use of software, improve the user's sense of software.

In the APPDELEGATE.M file

-(BOOL) Application: (UIApplication *) application didfinishlaunchingwithoptions: (nsdictionary *) launchOptions
{
Self.window = [[UIWindow alloc] initwithframe:[[uiscreen mainscreen] bounds]];

NSString *key = @ "Cfbundleversion";

Remove the version number of the last-used software stored in the sandbox
Nsuserdefaults *defaults = [Nsuserdefaults standarduserdefaults];
NSString *lastversion = [defaults stringforkey:key];

Get the version number of the current software
NSString *currentversion = [NSBundle Mainbundle].infodictionary[key];

if ([CurrentVersion isequaltostring:lastversion]) {
Show status bar, old version does not show new features
Application.statusbarhidden = NO;

Self.window.rootViewController = [[Iwtabbarviewcontroller alloc] init];
} else {//new version shows new
Self.window.rootViewController = [[Iwnewfeatureviewcontroller alloc] init];
Store new version
[Defaults setobject:currentversion Forkey:key];
[Defaults synchronize];
}
[Self.window makekeyandvisible];
return YES;

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Determine if the software is the first time to start