Core Data Integer changing value?

问题

i have a problem with core data storing integer (i chose int16 because they have a maximum of 6 signs).

my model holds

Entity: 'Expense'
the attribute in question is:


@property (nonatomic, retain) NSNumber * month;

it was automatically implemented as NSNumber by Xcode (Editor > createManagedmodelsubclass)

month holds an short identifier for every month. example

201203     //would be march of 2012

i store new entities with this snippet:

[newExpense setValue:monthNumber forKey:@"month"];

which works just fine. monthNumber has always the right value before i store it.

i retrieve objects with a fetching method and store them in an array called allExpenses. the array count is true and i have the right amount of entities in it.

now i do this:

NSMutableArray *thisMonthExpenses = [[NSMutableArray alloc]init ];

for (Expense *entity in allExpenses) {
    int tempMonth = [[entity month]intValue];
    if (tempMonth == month) {
        [thisMonthExpenses addObject:entity];

    }
}

to filter out the right entities that belong to the current month.

month // is an integer that holds the encoded month (again: correctly!)

but somehow the code:

int tempMonth = [[entity month]intValue];

does not return 201203, but strangly 4595 (always the same value).

the same happens with this code:

for (Expense *entity in monthExpenses) {
    if ([entity day].intValue == todayNumber.intValue) { //HERE ENTITY DAY.INTVALUE RETURNS A COMPLETELY WRONG INTEGER!
        [thisDayExpenses addObject:entity];
    }
}

i seem to be missing something - but i cannot figure out what, i tried around for 2 hours now and always get the wrong int value after reading my entities..

any ideas?

回答1:

201203 is 0x311F3, while 4595 is 0x11F3 — so what's happening is, you're losing the most significant byte. It sounds like in CoreData you have the number set as a 16-bit integer, which isn't capable of storing the number you want (16 bits can only represent up to the low five digits in decimal). It should be a 32-bit integer.

回答2:

have you tried

Expense.month = monthNumber;

[Expense setMonth:monthNumber];

来源：https://stackoverflow.com/questions/9610592/core-data-integer-changing-value

标签

objective-c

ios

core-data