I am customizing a JTree so some nodes have checkboxes, using santhosh tekuri's work as a base.
So the idea is writing a custom TreeCellRenderer, which in this case extends JPanel and implements TreeCellRenderer, and then at the method getTreeCellRendererComponent I have to decide for each node if it is receiving a checkbox or not.
I have seen some other examples for a typical JTree to customize each node icon, but they relay on converting each node to a JLabel and getting its text, while here it is a JPanel.
This is how my renderer looks like:
public class CheckTreeCellRenderer extends JPanel implements TreeCellRenderer{
private CheckTreeSelectionModel selectionModel;
private TreeCellRenderer delegate;
private TristateCheckBox checkBox;
protected CheckTreeManager.CheckBoxCustomizer checkBoxCustomer;
public CheckTreeCellRenderer(TreeCellRenderer delegate, CheckTreeSelectionModel selectionModel){
this.delegate = delegate;
this.selectionModel = selectionModel;
this.checkBox = new TristateCheckBox("");
this.checkBox.setOpaque(false);
setLayout(new BorderLayout());
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);
// Inside this if clause, those cells which do not require checkbox will be returned
if({CODE_TO_GET_NODE_TEXT}.startsWith("A")){
return renderer;
}
TreePath path = tree.getPathForRow(row);
if(path != null){
if(checkBoxCustomer != null && !checkBoxCustomer.showCheckBox(path)){
return renderer;
}
if(selectionModel.isPathSelected(path, selectionModel.isDigged())){
checkBox.getTristateModel().setState(TristateState.SELECTED);
}
else{
checkBox.getTristateModel().setState(selectionModel.isDigged() && selectionModel.isPartiallySelected(path) ? TristateState.INDETERMINATE : TristateState.DESELECTED);
}
}
removeAll();
add(checkBox, BorderLayout.WEST);
add(renderer, BorderLayout.CENTER);
return this;
}
}
In this case I want to avoid setting a Tristate checkbox for those cells whose texts starts with "A" as an example. But I can't find a way to get the text from the value argument.
In case it helps, this is how I create the JTree:
DefaultMutableTreeNode root = new DefaultMutableTreeNode();
JTree tree = new JTree(root);
// Add nodes to the tree
DefaultMutableTreeNode friends_node = new DefaultMutableTreeNode("Friends");
friends_node.add(new DefaultMutableTreeNode("Anna"));
friends_node.add(new DefaultMutableTreeNode("Amador"));
friends_node.add(new DefaultMutableTreeNode("Jonas"));
friends_node.add(new DefaultMutableTreeNode("Mike"));
friends_node.add(new DefaultMutableTreeNode("Anthony"));
friends_node.add(new DefaultMutableTreeNode("Maya"));
friends_node.add(new DefaultMutableTreeNode("Pepe Vinyuela"));
root.add(friends_node);
tree.setCellRenderer(renderer = new CheckTreeCellRenderer(tree.getCellRenderer(), new CheckTreeSelectionModel(tree.getModel(), dig)));
Any idea?
If you're using String userObject = "Anna";
new DefaultMutableTreeNode(userObject);
, then you might be able to use the DefaultMutableTreeNode#getUserObject() method:
@Override 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);
if (value instanceof DefaultMutableTreeNode) {
Object userObject = ((DefaultMutableTreeNode) value).getUserObject();
// Inside this if clause, those cells which do not require checkbox will be returned
if(userObject instanceof String && ((String) userObject).startsWith("A")){
return renderer;
}
//...