在初始化settings.bundle之前设置默认值的解决方法

Question

(I'm new to IOS and Objective-C so please excuse any miss-use of terminology...) In my app I have chosen to use the settings.bundle to store my app settings but when the app is first installed and before the user navigates to Settings on their IOS device it does not load the defaults. I have read many posts explaining that the app should create its own defaults until the settings.bundle has been 'initialised'.

To do this I have written some code that reads in the settings.bundle and creates an array accordingly. But if settings.bundle has not been initialised it creates a default array to be used in the interim. I suspect that my problem is with the following line of code where I am using a logical AND operator (probably incorrectly...):

if (!([swimtypeendurance isEqualToString:@"ON"]) && !([swimtypeendurance isEqualToString:@"OFF"]))

The problem is that I cannot get a true result for the if statement above, my app always executes the 'else'. My understanding of settings.bundle is that if they have not been initialised then the switch is neither ON or OFF as if it has no value. I am therefore testing to see if the string for swimtypeendurance is neither ON or OFF, in other words if it is not ON AND it is not OFF - hence my attempted use of the ! and &&...

Perhaps a better way to exaplain what I am doing is: I am testing the value of one of my settings from settings.bundle to see if it is either on or off. If it is one of the two states then I assume that the settings bundle has been initialised and all settings can be used, if not ie it is stateless then I create an array to be used until the user does initialise settings.bundle.

Here is the complete snippet of code to provide context to the question:

NSMutableArray* arrayofswimtypes = [NSMutableArray arrayWithCapacity:15];
    NSString *swimtt750 = [defaults boolForKey:kswimtypett750mKey]? @"ON" : @"OFF";
    if ([swimtt750 isEqualToString:@"ON"]) {
        swimTypeTt750m = [[NSString alloc] initWithFormat:@"Time Trial - 750m"];
        [arrayofswimtypes addObject:[[NSString alloc] initWithFormat:@"%@", swimTypeTt750m]];
    }
    NSString *swimtt1500 = [defaults boolForKey:kswimtypett1500mKey]? @"ON" : @"OFF";
    if ([swimtt1500 isEqualToString:@"ON"]) {
        swimTypeTt1500m = [[NSString alloc] initWithFormat:@"Time Trial - 1500m"];
        [arrayofswimtypes addObject:[[NSString alloc] initWithFormat:@"%@", swimTypeTt1500m]];
    }

    [arrayofswimtypes addObject:[[NSString alloc] initWithFormat:@"General Session"]];

    NSString *swimtypedrills = [defaults boolForKey:kswimtypedrillsKey]? @"ON" : @"OFF";
    if ([swimtypedrills isEqualToString:@"ON"]) {
        swimTypeDrills = [[NSString alloc] initWithFormat:@"Drills Session"];
        [arrayofswimtypes addObject:[[NSString alloc] initWithFormat:@"%@", swimTypeDrills]];
    }
    NSString *swimtypeendurance = [defaults boolForKey:kswimtypeenduranceKey]? @"ON" : @"OFF";
    if ([swimtypeendurance isEqualToString:@"ON"]) {
        swimTypeEndurance = [[NSString alloc] initWithFormat:@"Endurance Session"];
        [arrayofswimtypes addObject:[[NSString alloc] initWithFormat:@"%@", swimTypeEndurance]];
    }

    //Place an if-else statement in here to load a default array if the user has not been to settings and initialised the settings.bundle
    if (!([swimtypeendurance isEqualToString:@"ON"]) && !([swimtypeendurance isEqualToString:@"OFF"])) {
        swimSessTypesArray = [[NSMutableArray alloc] initWithObjects:[[NSString alloc] initWithFormat:@"Time Trial - 750m"],
                              [[NSString alloc] initWithFormat:@"Time Trial - 1500m"], 
                              [[NSString alloc] initWithFormat:@"General Session"],
                              [[NSString alloc] initWithFormat:@"Drills Session"],
                              [[NSString alloc] initWithFormat:@"Endurance Session"], nil];
        NSLog(@"Count of swimSessTypesArray NOT FROM Defaults: %i", [swimSessTypesArray count]);
    } else {
        swimSessTypesArray = arrayofswimtypes;
        NSLog(@"Count of swimSessTypesArray from Defaults: %i", [swimSessTypesArray count]);
    }

Any hints and comments on this would be massively appreciated including any improvements that I can make to my coding based on your superior knowledge and experience.

Many thanks in advance for your assistance...

Answer 1

OK, the comment from Matthias has led me to my working solution. Essentially there are two common methods for testing if the settings.bundle for your app have been initialised by the user and set defaults to be used if not: 1) use registerDefaults and 2) create your own tests by using some IF-ELSE statements. Since the question is related to the latter of the two options I will answer it and not the registerDefaults method.

The first thing that one should know is that boolForKey will return a NO under 2 different conditions: firstly when the key does not exist (effectively when the settings bundle has not been initialised by the user) and when it is set to the no of OFF position. This makes it very impossible to test using boolForKey but if you use objectForKey to test whether or not the key exists then it works perfectly. The code looks like this (in keeping with the example code from the question):

if (![boolForKey:kswimtypeednurancekey]) {
Create your default settings to be used by the app;
} else {
Use the settings from the settings.bundle;
}