Java-在另一个实例中添加抽象类的实例

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 :)

Answer 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.

Answer 2

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?)

Answer 3

疯狂地猜测，因为这取决于您的代码...试试这个（除非Piotr说了什么）

profilo_2.add(profilo_2.createButton());

Answer 4

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