![]() An expanded node is a non-leaf node that will display its children when all its ancestors are expanded.How to Write a Tree-Will-Expand Listener.Ī specific node in a tree can be identified either by a TreePath, an object that encapsulates a node and all of its ancestors, or by its display row, where each row in the display area displays one node. ![]() How to Write a Tree Expansion Listener and A program can detect changes in branch nodes' expansion state by listening for tree expansion or tree-will-expand events, as described in By default, all branch nodes except the root node start out collapsed. Typically, the user can expand and collapse branch nodes making their children visible or invisible by clicking them. Nodes that can not have children are leaf nodes.īranch nodes can have any number of children. We refer to nodes that can have children whether or not they currently have children as branch nodes. By default, the tree displays the root node, but you can decree otherwise. Every tree has a root node from which all nodes descend. Each row displayed by the tree contains exactly one item of data, which is called a node. Here is a picture of a tree:Īs the preceding figure shows, JTree displays its data vertically. ![]() Like any non-trivial Swing component, the tree gets data by querying its data model. A JTree object does not actually contain your data it simply provides a view of the data. JTree class, you can display hierarchical data.
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