为什么这会产生 NIL 值?
NSString *danceDateValue = self.yourvariable.text;
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"MM-dd-yy"];
NSDate *date = [dateFormat dateFromString: danceDateValue];
NSLog(@"date input value: %@", danceDateValue);
NSLog(@"date input value: %@", date);