Determine the first time iOS app starts someone else's hey

The popular solution is to use [Nsuserdefaults standarduserdefaults a key in most places, if it doesn't exist, which means that this is the Application launcher, otherwise it's not the first time

In APPDELEGATE.M, locate the "Application:didfinishlaunchingwithoptions:" Method and add the following code:

if (![[NSUserDefaults standardUserDefaults] boolForKey:@ "everLaunched" ]) {     [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@ "everLaunched" ];     [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@ "firstLaunch" ]; } else {     [[NSUserDefaults standardUserDefaults] setBool:NO forKey:@ "firstLaunch" ]; } 总的解决办法是 2 个key: @”everLaunched”判断用户以前是否登录,   @”firstLaunch” 用来开发者在程序的其他部分判断. 在第一次启动的时候 key @”everLaunched” 不会被赋址的, 并且设置为YES. @”firstLaunch” 被设置为 YES. 在程序的其他部分用以下代码判断: if ([[NSUserDefaults standardUserDefaults] boolForKey:@ "firstLaunch" ]) {     // 这里判断是否第一次 UIAlertView *alert=[[UIAlertView alloc] initWithTitle:@ "第一次"    message:@ "进入App"                                                                delegate:self cancelButtonTitle:@ "我知道了" otherButtonTitles:nil]; [alert show]; [alert release]; } The first piece of code runs key @ "Firstlaunch" will be set to NO

Determine the first time iOS app starts someone else's hey