从用户默认值获取值并创建NSMutableDictionary

Question

I am trying to create a dictionary which is a replica for NSUserdefaults. I want the dictionary to contain same values and keys. But, we need to convert bool and int values to NSNumber when we save it to dictionary. Right now i am doing the following. But not sure which value is bool value and int value. If I can get to know the type of the value I can do rest. Is there any way to check the value whether it is bool or int.

NSArray *availableUserDefaultsKeys = [NSArray arrayWithObjects:@"Key1", @"Key2",nil];
NSMutableDictionary *userDefaultsDictionary = [NSMutableDictionary dictionary];
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];

for (NSString *key in availableUserDefaultsKeys) {
    id value = [userDefaults objectForKey:key];
    if (value != nil) { // Is there any way to check whether the value is bool or int here
        [userDefaultsDictionary setObject:value forKey:key];
    } else {
        [userDefaultsDictionary setObject:[NSNull null] forKey:key];
    }
}

I have checked the debug.plist which has all the user defaults stored, In that we have type field where it specifies the type. Can we get the type from this field.

Answer 1

You can use this way:

// v is NSNumber
if ((strcmp([v objCType], @encode(BOOL) == 0) {
    // this is BOOL
}

And there are @encode(int) @encode(float)

You should avoid directly saving seperated data to NSUserDefaults, you can pack them in an object, and this object should conform NSCoding protocol. Then after you read the data out, you will know the exact type.