How iOS can tell the app to start for the first time

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

1. if (![ [Nsuserdefaults Standarduserdefaults] boolforkey:@ "everlaunched"]) {
2. [[Nsuserdefaults Standarduserdefaults] setbool:yes forkey:@ "everlaunched"];
3. [[Nsuserdefaults Standarduserdefaults] setbool:yes forkey:@ "Firstlaunch"];
4. }
5. else{
6. [[Nsuserdefaults Standarduserdefaults] setbool:no forkey:@ "Firstlaunch"];
7. }

The total solution is 2 key: @ "everlaunched" to determine if the user has previously logged in,

@ "Firstlaunch" is used by developers to judge in other parts of the program.

At the first boot, key @ "everlaunched" is not assigned and is set to Yes. @ "Firstlaunch" is set to YES.

In other parts of the program, use the following code to determine:

2. if ([[[Nsuserdefaults Standarduserdefaults] boolforkey:@ "Firstlaunch"]) {
4. Here to determine whether the first time
6. Uialertview *alert=[[uialertview Alloc] initwithtitle:@ "First time"
8. message:@ "Go to App"
10. Delegate:self
12. cancelbuttontitle:@ "I know."
14. Otherbuttontitles:nil];
16. [Alert show];
18. [Alert release];
22. }

The first piece of code running key @ "Firstlaunch" will be set to NO.

Transferred from: http://blog.csdn.net/justinjing0612/article/details/7306836

How iOS can tell the app to start for the first time