Set icon to each node in Jtree

java, jtree, swing, treecellrenderer, treenode

Solution

You can change default UI values for icons of `JTree` nodes without any custom renderer:

URL resource = logaff.class.getResource(IMAGE);
Icon icon = new ImageIcon(resource);

UIManager.put("Tree.closedIcon", icon);
UIManager.put("Tree.openIcon", icon);
UIManager.put("Tree.leafIcon", icon);

or use something like next:

@Override
public Component getTreeCellRendererComponent(JTree tree,
    Object value, boolean selected, boolean expanded,
    boolean leaf, int row, boolean hasFocus) {
        super.getTreeCellRendererComponent(tree, value, selected,expanded, leaf, row, hasFocus);
        DefaultMutableTreeNode nodo = (DefaultMutableTreeNode) value;
        if (tree.getModel().getRoot().equals(nodo)) {
            setIcon(root);
        } else if (nodo.getChildCount() > 0) {
            setIcon(parent);
        } else {
            setIcon(leaf);
        }
        return this;
}

Also read about rendering mechanism.

Problem

I want to set a different icon for each node in my JTree component. I'm loading each node from a database using a `while` loop. I set each icon like a root, leaf, or parent. I set them as follows: All my declarations are global: ``` private ResultSet myResultSet; protected DefaultTreeModel treeModel; private DefaultMutableTreeNode rootNode,childNode,parent1,parent2; ``` This is how I set my nodes: ``` myResultSet=rtnNodes(); /*Method that returns a RS with my nodes*/ while(myResultSet.next()){ switch(myResultSet.getInt(1)){ /*The first column is the type of node: root, parent, leaf...*/ case 0: treeModel = new DefaultTreeModel((rootNode=new DefaultMutableTreeNode(myResultSet.getString(2)))); break; /*root node*/ case 1: case 4: parent1 = parent2 = makeNode(rootNode); break; /*parent node*/ case 2: makeNode(parent2); break; /*leaf node*/ case 3: parent2 = makeNode(parent1); break; /*sub patern node*/ } /*makeNode is the method where I create the nodes*/ } ``` The `makeNode` method is this: ``` public DefaultMutableTreeNode makeNode(DefaultMutableTreeNode parent){ //The second column in the RS is the name of the node treeModel.insertNodeInto((childNode=new DefaultMutableTreeNode(myResultSet.getString(2))),parent,parent.getChildCount()); return childNode; } ``` After filling the `treemodel` with my nodes, I set the model to my JTree: ``` myJTree.setModel(treeModel); myJTree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION); ``` But the problem comes when I try to set the icons. I create a subclass called MyTreeRenderer, and I use this: ``` myJTree.setCellRenderer(new MyTreeRenderer()); ``` But it doesn't set the icons as I want, the subclass is: ``` private ImageIcon root,parent,leaf; public MyTreeRenderer() { root=setIcons(2); /*setIcons is a method that I dont publish in this post, that helps me to set the path of the icons*/ parent=setIcons(3); leaf=setIcons(4); } @Override public Component getTreeCellRendererComponent(JTree tree,Object value,boolean selected,boolean expanded,boolean leaf,int row,boolean hasFocus){ super.getTreeCellRendererComponent(tree,value,selected,expanded,leaf,row,hasFocus); DefaultMutableTreeNode nodo = (DefaultMutableTreeNode)value; TreeNode t = nodo.getParent(); if(t!=null){ setIcon(root); } return this; } ``` How can I set the icon for each node without using his name? The code of the subclass, as is, set all the nodes with the same icon, and each time I select a node in the jtree, the `getTreeCellRendererComponent` runs, I don´t want this.

Original source

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