Question

I am having troubles with my class which reads and writes data to a plist. Here is some code:

This first chunk is from my custom class with all my plist read and write methods.

-(NSString *) dataFilePath{
    NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentDirectory = [path objectAtIndex:0];
    return [documentDirectory stringByAppendingPathComponent:@"userInformation.plist"];
}

-(bool)readUserIsMale{
    NSString *filePath = [self dataFilePath]; 
    if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]) {        
        NSDictionary *boolDict = [[NSDictionary alloc] initWithContentsOfFile:[self dataFilePath]];
        return [[boolDict objectForKey:@"boolUserIsMale"] boolValue];
    }
    return nil;
}

-(void)writeUserIsMale:(bool)boolValue{
    NSDictionary *boolDict = [[NSDictionary alloc] init];
    [boolDict setValue:[NSNumber numberWithBool:boolValue] forKey:@"boolUserIsMale"];
    [boolDict writeToFile:[self dataFilePath] atomically:YES];
}

I then in another class where desired import, create and use the class methods:

#import "plistReadWrite.h"
plistReadWrite *readWrite;

If I try and see its value in the console I get (null) return.

NSLog(@"%@",[readWrite readUserIsMale]);

This is of course after I have written some data like so:

[readWrite writeUserIsMale:isUserMale];

isUserMale being a bool value.

Any help would be massively appreciated, if you need anymore info let me know. Thanks.

Answer 1

I think this is mostly correct. In your writeUserIsMale: method you want a mutable dictionary, so you can actually set that key (this should have crashed for you as is, so I’m guessing a copy/paste problem?)

//NSDictionary *boolDict = [[NSDictionary alloc] init];
//should be:

NSMutableDictionary *boolDict = [[NSMutableDictionary alloc] init];

And then when you log the value, remember that bool (or BOOL) are primitives, not objects so:

NSLog (@"%d",[readWrite readUserIsMale]); // Will print 0 or 1
// or if you prefer:
NSLog (@"%@", ([readWrite readUserIsMale]? @"YES":@"NO")); // print YES or NO

Lastly, since this is objective-c, I would probably use BOOL instead of bool.

I’m assuming this is just a simple example, and that you know about NSUserDefaults for this sort of thing.

Hope that helps.