Java / Swing-将组件添加到JList

Question

I have a JList that I need to add Components to. What I have done is I have made a DefaultListModel that takes the type of a Component I have made. My code adds it to the DefaultListModel, and it does display information, but it is just the components name in String format. How should I make it actually display the component instead of the component's name? Is it even possible?

Here is my code

    DefaultListModel<CustomComponent> jListModel = new DefaultListModel<>();
jListModel.addElement(new CustomComponent()); //Adds the name of the component(not what I want)

Answer 1

Implement your ListCellRenderer class In the method

Component getListCellRendererComponent(
    JList<? extends E> list,
    E value,
    int index,
    boolean isSelected,
    boolean cellHasFocus);

All you need is to return value . The value is list element in your case it's the CustomComponent instance. It's simplest approach.

But it's not correct approach. List model should keep data (not component). Instead define one instance of CustomComponent for the renderer and in the getListCellRendererComponent() call something like customComponentInstance.init(value) to let the CustomComponent reflect data from model.

Answer 2

It is possible. You need to write your own ListCellRenderer, which returns your Component, instead of the default JLabel.

Example:

public class ComponentListCellRenderer {

    public ComponentListCellRenderer() {
    }

    public Component getListCellRendererComponent(JList<?> list, Object value, int            index, boolean isSelected, boolean cellHasFocus) {
    Component c = super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
        if (value instanceof Component){
            c = (Component) value;
            c.setPreferredSize(c.getSize());
        }

        return c;
    }

}

In this case the default Component c is intercepted and exchange with your own Component, which would be value . We need to set the preferred size of your Component to it´s size, or else the JList won´t display the Component not correctly.

How to use:

• Create a new JList<CustomComponent>()
• set it´s ListCellRenderer to a new ComponentListCellRenderer