subclass

I'm having a problem with multi-table inheritance in django. Let’s make an example with bank accounts. class account(models.Model): name = models…… class accounttypeA(account): balance = models.float….. def addToBalance(self, value): self.balance += value class accounttypeB(account): balance = models.int…. # NOTE this def addToBalance(self, value): value = do_some_thing_with_value(value) # NOTE this self.balance += value Now, i want to add a value to an accounttype, but all i have is an account object, for instance acc=account.object.get(pk=29) . So, who is the child of acc ? Django

I'm building an iOS app in Swift and drawing on the Lister sample project Apple provides. Lister uses two model objects: List and ListItem. I found that both of them do not call super.init() in their initializers even though they subclass NSObject. However, in the Objective-C version of Lister, both model objects (AAPLList and AAPLListItem) do call [super init] . The Swift Programming Language clearly states that “designated initializers must call a designated initializer from their immediate superclass.” (Rule 1 of Initializer Chaining in Initialization) What's going on here? Why is this an

Say I have a Class called ParentClass and a Class called ChildClass The ParentClass is abstract and the ChildClass extends the ParentClass per Java terminology. Furthermore, the ParentClass has a constructor which takes an int as a parameter. Now in another class I want to instantiate the ChildClass . I have tried the two below ways: ChildClass obj1 = new ChildClass(5) ParentClass obj2 = new ChildClass(5) Java allows me to use any of the two above ways. My question is, is there actually any difference? Can I use the two, interchangeably if I want to ? Both work, and both create the same object

I have this code segment: if (cell == nil) { CGRect cellFrame = CGRectMake(0,0,300,250); cell = [[UITableViewCell alloc] initWithFrame:cellFrame reuseIdentifier:CellTableIndetifier]; CGRect nameLabelRect = CGRectMake(0, 5, 70, 20); UILabel* nameLabel = [[UILabel alloc] initWithFrame:nameLabelRect]; nameLabel.textAlignment = NSTextAlignmentCenter; nameLabel.text = @"Name"; nameLabel.font = [UIFont boldSystemFontOfSize:12]; [cell.contentView addSubview: nameLabel]; CGRect colorLabelRect = CGRectMake(0, 25, 70, 20); UILabel* colorLabel = [[UILabel alloc] initWithFrame:colorLabelRect]; colorLabel

I'm currently working on a custom UIControl Subclass. To track the touches I use the following Method: - (BOOL)beginTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event { NSLog(@"Start"); CGPoint location = [touch locationInView:self]; if ([self touchIsInside:location] == YES) { //Touch Down [self sendActionsForControlEvents:UIControlEventTouchDown]; return YES; } else { return NO; } } This works as expected and @"Start" is loged exactely once. The next step is that I add a Target and a Selector with UIControlEventTouchDown. [markItem addTarget:self action:@selector(action:)