Java - Add an instance of an abstract class in another instance

Question

I have this piece of code :

public class Profile extends Container{
    public Profile(String value) {
        Container profilo_1 =new Container();
        Container profilo_2 =new Container();

        // (1) THIS ADD A BUTTON TO THE MAIN CLASS
        this.createButton().setLabel("Modifica Profilo");

        // (2) NOW I NEED TO ADD A BUTTON INTO THE INSTANCE OF profilo_2 BUT IT FAILS
        profilo_2.add(this.createButton());

        this.add(profilo_1);
        this.add(profilo_2);        
    }
}

the point (2) fails, because it said that im about to adding a child to this container, but it is owner already by a container...

In fact, if i do this :

ILabel label=new ILabel();
profilo_2.add(label);

it said to me that ILabel() is abract and cannot be instantiated!

How can I fix it? Cheers to everybody :)

Flavio · Accepted Answer · 2010-11-11 14:59:49Z

1

Guessing wildly, since this depends on your code... Try this (moreless what Piotr said)

profilo_2.add(profilo_2.createButton());

answered Nov 11, 2010 at 14:59

Flavio

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4 Comments

Piotr Over a year ago

Do you get an exception or does it simply not work? By the way, what framework are you using? I am guessing it is some UI framework? In that case, we can probably help you if you tell us which one.

markzzz Over a year ago

i resolved :) With this profilo_2.createButton().setLabel("EDIT"); it works!! Just i call directly the instance of the container. Thanks, and yes it is a UI Framework :) p.s. as info, how can i "bold" my text in this stackoverflow comment box? I don't know the bbcode hehe

markzzz Over a year ago

But now (for example) if i need to access to methods of that object (the Button created into profilo_2 when i call profilo_2.createButton()) how can I do it?

Flavio Over a year ago

Button b = profilo_2.createButton(); b.setLabel("EDIT"); b.setXYZ(); and so on. The class name Button depends on what createButton() returns.

robev · Accepted Answer · 2010-11-11 14:53:03Z

1

Try changing to

Button button2 = this.createButton();
button2.setLabel("EDIT");
profilo_2.add(button2);

By the way this has nothing to do with abstract classes, from what I see

EDIT: Though you say that #1 "adds a button to the main class", so does that mean that createButton() does this.add(button) ? If so then you should probably change that function so that isn't done every time you create a button.

answered Nov 11, 2010 at 14:53

robev

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1 Comment

markzzz Over a year ago

yes if i do this.createButton(); it the same of this.add(button);

Piotr · Accepted Answer · 2010-11-11 14:54:20Z

1

The problem is probably that when you create a button with "this.createButton", that button has its parent set to "this" (in this context), and when you try to add it to profilo_2, it throws an error. Instead you should createButton on profilo_2 directly, then the parent will be the correct one (and perhaps you won´t have to add() it either?)

answered Nov 11, 2010 at 14:54

Piotr

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1 Comment

markzzz Over a year ago

yes but how can i do it? See the topic, i edited it with more further info!

khachik · Accepted Answer · 2010-11-11 14:52:09Z

0

Probably, setLabel() returns something which cannot be passed to Container::add(..). Please provide your code for Container

answered Nov 11, 2010 at 14:52

khachik

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