java swing -为我的JTree节点添加颜色

Question

我已经创建了一个下面的渲染器，它渲染带有复选框的JTree，我想要添加不同的颜色和图标到不同的节点。我该怎么做呢？请帮帮我。提前谢谢你。

class CheckTreeCellRenderer extends JPanel implements TreeCellRenderer {
private CheckTreeSelectionModel selectionModel;
private TreeCellRenderer delegate;
private TristateCheckBox checkBox = new TristateCheckBox("",null,true);
public static final State NOT_SELECTED = new State();
public static final State SELECTED = new State();
public static final State DONT_CARE = new State();

public CheckTreeCellRenderer(TreeCellRenderer delegate, CheckTreeSelectionModel selectionModel) {
    this.delegate =  delegate;
    this.selectionModel = selectionModel;
    setLayout(new BorderLayout());
    setOpaque(false);
    checkBox.setState(Boolean.TRUE);
    revalidate();
    checkBox.setOpaque(false);
}

public Component getTreeCellRendererComponent
        (JTree tree, Object value, boolean selected, boolean expanded,
        boolean leaf, int row, boolean hasFocus) {

    Component renderer = delegate.getTreeCellRendererComponent
            (tree, value, selected, expanded, leaf, row, hasFocus);

    TreePath path = tree.getPathForRow(row);

    if(path!=null){
        if(selectionModel.isPathSelected(path, true)) {
            checkBox.setState(Boolean.TRUE);
        }
        else {
            checkBox.setState
                    (selectionModel.isPartiallySelected(path) ? null : Boolean.FALSE);
        }
    }
    setBackground(Color.pink);

    removeAll();
    add(checkBox, BorderLayout.WEST);
    add(renderer, BorderLayout.CENTER);
    return this;
}    

}

Answer 1

了解TreeCellRenderers的最好地方是从tutorial (在页面底部)。

而不是添加renderer到BorderLayout.CENTER，您可以只添加一个不同的图标，任何你喜欢的颜色。

Answer 2

为了使您的setBackground(Color.PINK)具有任何可见的效果，您应该在构造函数中将setOpaque(false)更改为setOpaque(true)。也就是说，我赞同@John的建议，即在Sun教程中阅读有关渲染器的内容。