Changing NSDate on custom object?

My app has a custom object that contains an NSDate. I want to change this NSDate in my app, but this is not possible?

Code:

So this is a method from my object, that is supposed to alter the date, depending on another variable (sentcount):

(void)increaseSentAttempts
{
sentCount++;

NSDate *cal = [NSDate date];

if (sentCount < 3) {
    //add 1 minute
    cal = [cal dateByAddingTimeInte开发者_Python百科rval:60];
}
else if(sentCount < 10)
{
    //add 5 minutes
    cal = [cal dateByAddingTimeInterval:300];
}
else if(sentCount < 23)
{
    //add 1 hour
    cal = [cal dateByAddingTimeInterval:3600];
}
else {
    //add 15 hours
    cal = [cal dateByAddingTimeInterval:54000];
}


//sæt nextsent attribut
nextSendAttempt = cal;

}

nextSendAttempt is my NSDate in the custom object. But seeing as the app crashes, the nextsendattempt = cal; isnt possible.

Have you set a property on the NSDate-Member of your custom object?

@interface MyClass : NSObject
{
    NSDate *myDate;
}
@property (retain) NSDate *myDate;
@end;

To change that value:

MyClass *obj = ...;
NSDate *newDate = ...;
NSLog(@"oldDate: %@",obj.myDate);
obj.myDate = newDate;
NSLog(@"newDate: %@",obj.myDate);

Stupid stupid me. I needed to write:

self.nextSendAttempt = cal;

That'll work perfectly.

Sorry for wasting your time :)