A fast, easy to use, free, and community supported 2D game engine
bsharp42
Member
Hello,
I have several field such as high scores/highest level, etc that I need to save.
I will be saving the scores on an iphone device basis (Basically like Flight Control), NOT on "who played it" basis which requires you to input your name each time you end a game.
So basically I need to save around 5 numbers (integers). I looked through the demos and it doesn't seem to have a good example of this ???
Anybody got a good instruction or tutorial on how to do this ?
Use presistence and you can save a whole array with it, it works like so:
NSUserDefaults is a singelton.
//Saving.
//Saves and object and assigns a key for retrival.
[[NSUserDefaults standardUserDefaults] setObject:myObject forKey:@"myObject"];
//Tells the userDefaults to update the data base.
[[NSUserDefaults standardUserDefaults] synchronize];Note that the setObject may vary, if saving an integer it would be setInteger: forKey
//Retrieving Data.
id myObject = [[NSUserDefaults standardUserDefaults] objectForKey:@"myObject"];Defaults is not a very fast system and not too powerful, mainly used to save small stuff, not recommended to use on saving game state and such.
Saving game score would be quite easy with this, and the item gets saved in local application data, so it's quick and easy to implement.
score (int):
`int myScore;
...... //myScore updates...
- (void)saveScore {
[[NSUserDefaults standardUserDefaults] setInteger:myScore forKey:@"score"];
//Note that the synchronize method can be called when exiting the app or such.
//I prefer sync whenever I update the database, but it's advised to save at//Application will terminate, //or use the Director in that case...
[[NSUserDefaults standardUserDefaults] synchronize];
}
bsharp42
Member
Thank you much for the response, but I don't seem to be getting the right value.
After the game ends, I call this code
[[NSUserDefaults standardUserDefaults] setInteger:3 forKey:@"score"];
[[NSUserDefaults standardUserDefaults] synchronize];
3 is there for testing purpose.
When I go to the stats page to retrieve it with
int x = (int)[[NSUserDefaults standardUserDefaults] objectForKey:@"score"];
x doesn't get the right value.
It says that x = 15303888
Does it matter that I'm calling those two functions in two different separate classes ...?
you mistake is in the retrieve method, you tried to retrieve an object instead of an integer. Correct code:
int x = [[NSUserDefaults standardUserDefaults] IntegerForKey:@"score"];
should work...
Note: The valueForKey differs by the type of value you want to retrieve, if an object: objectForKey: if it's a BOOL: BoolForKey:.
Hmm I don't know, I'm not really into users changing stuff.
The defaults basically get saved as a .plist (I think?) on your application's documents library. So basically a good enough user with a jailbroken iPhone could probably alter it.
Hacks are always available, no matter how much you fight against it, you are sure to lose.
What I do is except saving my data, saving my custom MD5 hash values for that data also. So when I load settings, I compare data and its hash value, and if anything is changed I reset all the data to default values...
Yes, something like that:
1. save original score as int for key @"Score"
2. save MD5 string for score as string for key @"MD5_Score"
and in runtime compare those values. Though I don't just make MD5 from integer, but first convert it to string, append some "private" string to it and then make MD5. Also, at runtime I compare with same method.
well, at least to make hacking a little more fun^h^h^h difficult!
Eh, if they really want to crack it, nothing would stop 'em. But for some enthusiast who just want to alter plist file, those methods would be more then enough. And I am not polite with displaying some message, if they change anything I just reset all their scores to zero ;)
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