get list of checked checkboxes through arraycontroller

Question

i have an arraycontroller bound to the tableview. i need to return the number of checked checkoxes in the table. the arraycontroller is filled with nsmutabledictionaries. this is the code i have so far:

-(IBAction)getlist:(id)sender{
checkedchecks = 0;
for (NSManagedObject *a in imagescontroller.arrangedObjects)
{

 ////MISSING CODE GOES HERE
}
NSAlert *alert = [[NSAlert alloc] init] ;
[alert setMessageText:[NSString stringWithFormat:@"%ld",(long)checkedchecks ]];
[alert runModal];

}

now i would need to know how i can count all the values that are boolean and are set to yes.. thanks!

Answer 1

Actually, I think you do not have to loop through your objects.

NSUInteger checked = [(NSNumber*)[imagesController.arrangedObjects
                valueForKeyPath:@"@sum.boolProperty"] integerValue];

This is sort of a hack because a BOOL will be interpreted as 0 or 1.
The semantically more correct way is.

NSUInteger checked = [imagesController.arrangedObjects
                 filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:
                   @"boolProperty == %@", @YES]].count;

This is assuming that you have an array (arrangedObjects) which contains instances of NSManagedObject (or subclass thereof). The objects have a property called boolProperty of type NSNumber (which is the standard wrapper for BOOL values in managed objects). When a row is displayed, it is marked as checked if this boolProperty is @YES. If you change the checkmark (e.g. by selecting the row), the model should be updated: the appropriate managed object should be retrieved and the boolProperty toggled.