LWUIT: Custom List Renderer with checkboxes to select multiple items

[Mahendr Shinde]

I am learning LWUIT from last 2/3 days. I am having problem with Custom renderer for my List (LWUIT).
For individual components, (List Items)

public class SelectableListItem extends ListItem {
    private boolean selected;

    public boolean isSelected() {
        return selected;
    }

    public void setSelected(boolean selected) {
        this.selected = selected;
    }

    public SelectableListItem(String name, long size) {
        super(name,size);
        selected =false;
    }

}

and this is my custom renderer:

public class SelectableFileRenderer extends Container implements ListCellRenderer {

    private CheckBox check;
    private Label sizeLabel;
    private Image img;
    private Label focus;

    public SelectableFileRenderer() {
        super(new BoxLayout(BoxLayout.Y_AXIS));
        try {
            img = Image.createImage("/res/doc.png");
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        check = new CheckBox("", img);
        focus = new Label("*");
        addComponent(check);
        sizeLabel = new Label("");
        addComponent(sizeLabel);
    }

    public Component getListCellRendererComponent
            (List list, Object value, int index, boolean isSelected) {
        SelectableListItem item = (SelectableListItem) value;
        check.setText(item.getName());
[color=red]        item.setSelected(isSelected);
        check.setSelected(item.isSelected());[/color]
        focus.getStyle().setBgTransparency(200);
        sizeLabel.setText("size: " + item.getSize());
        return this;
    }

    public Component getListFocusComponent(List list) {
        return focus;
    }
}

I have tried many different ways to solve this but no success!
NOTE: code in RED color is newest addition: it makes only ONE item selected and makes other unchecked, but i don't want to uncheck other (means till the time i make them unchecked)

[Darryl Burke]

I'm not familiar with LWUIT, but I do know that it has similarities with Swing.

In your code, you are checking the isSelected parameter, which depends on the list's selection model. I would guess that what you really need is to ignore that parameter and use the isSelected() of the SelectableListItem.

And in general, don't ever change any model state in a renderer call (nor in custom painting code, if you write any). So start by getting rid of the line

item.setSelected(isSelected);

You probably need to toggle the selected state of the SelectableListItem in a selection listener, if LWUIT has such a beast.

[Mahendr Shinde]

Thanks for your reply,
i have made few changes to my code, i have shifted logic to make checkboxes select/deselect in Action Listener and i have removed that line which you have mentioned.