Saving incremental int variable - iphone

Question

I need to save a variable that increments every time a user hits a button within the app. I've been trying to do that with NSUserDefaults with no success. Here's the code I'm using:
[[NSUserDefaults standardUserDefaults] setInteger:i++ forKey:#"AppCount"];
When I output this in the log, however, I keep getting 0.
Any help would be greatly appreciated.

Answer 1

Try adding:
[[NSUserDefaults standardUserDefaults] synchronize];
After each time you change the value of your integer.
Quoting Apple's documentation on synchronize:
Writes any modifications to the persistent domains to disk and updates
all unmodified persistent domains to what is on disk.
http://developer.apple.com/library/ios/DOCUMENTATION/Cocoa/Reference/Foundation/Classes/NSUserDefaults_Class/Reference/Reference.html#//apple_ref/occ/instm/NSUserDefaults/synchronize
So with this modification, your final code should look like this:
[[NSUserDefaults standardUserDefaults] setInteger:i++ forKey:#"AppCount"];
[[NSUserDefaults standardUserDefaults] synchronize];
EDIT: Actually on second thought, give this a try:
I think the problem is using i++ assumes that the application will always be able to keep track of the count, and every time you re-enter the application i gets reset.
The following works, I just tested it.
if (![[NSUserDefaults standardUserDefaults] integerForKey:#"AppCount"]) {
[[NSUserDefaults standardUserDefaults] setInteger:i forKey:#"AppCount"];
}else{
[[NSUserDefaults standardUserDefaults] setInteger:[[NSUserDefaults standardUserDefaults] integerForKey:#"AppCount"] + 1 forKey:#"AppCount"];
}
[[NSUserDefaults standardUserDefaults] synchronize];

Answer 2

You can use Static NSUIInteger appCount=0;
in the function user taps increase it value appCount++;
that keeps the value in function calls within the app. after app closing you write it to file.

Answer 3

- (void)viewDidLoad {
[super viewDidLoad];
countFirst= [[NSUserDefaults standardUserDefaults]integerForKey:#"Counter"];
countFirst++;
}
Write this wherever you want to increment.
[[NSUserDefaults standardUserDefaults] setInteger:countFirst++ forKey:#"Counter"];