The first step in creating a TreeView control is declaring a TreeView You can also retrieve the most recently selected item by calling getSelectedItem.ĭetermines whether the root node should be visible. You can use the selection model to get an observable list of selected items by calling its getSelectedItems method. Returns the selection model for the list view control. MultipleSelectionModel getSelectionModel() The following table 6-6 shows the key constructors and methods ofĬreates a tree that displays the tree that starts at the specified node. You use the TreeView class to create a tree component that displays the With the task of creating a TreeView control to show off the tree. The complete tree is successfully created in memory, so I can get on With the root node specified as its parent. Here, makeShow is called to create a node for "CSS" The following code creates the root note of the tree. The list will be empty if the node happens to be a leaf node.Ĭreate or retrieve child nodes using the familiar methods of the The children of this node, represented as an ObservableList. The parent of this node, unless the node happens to be the root. The easiest way to set the user object is to Objects of any type you want for the user object.Ĭalls the user object's toString method to determine what text to In the following example, we use strings for the user objects, but you can use The value, which contains the data represented by the node. The TreeItem class provides three basic characteristics for each node: If there is no previous sibling, returns null. PrevSibling() Returns the previous sibling of this tree item. If there is no next sibling, returns null. NextSibling() Returns the next sibling of this tree item. IsLeaf() Returns a boolean that indicates whether the tree item is a leaf node (that is, has no children). IsExpanded() Returns a boolean that indicates whether the tree item is expanded. SetExpanded(boolean expanded) Specify true to expand the node. GetChildren() Returns an ObservableList that represents the children of this tree item. SetValue(T value) Sets the tree item's value. GetValue() Returns the tree item's value. To do that, use the TreeItem class, the details is listed in the following table.Ĭreates a tree node with the specified value. Here, T specifies the type of value held by the TreeItem.īefore you can actually create a tree view, you must first build the tree it TreeView is a generic class that is defined like this: TreeView automatically provides scrollbars when the size of the tree exceeds the dimensions of the view. The sequence of nodes that leads from the root to a specific node is called a path. Have no children, and branch nodes, which form the root nodes of sub trees.Ī sub tree is simply a tree that is part of a larger tree. TreeView implements a conceptually simple, tree-based data structure.Ī tree begins with a single root node that indicates the start of the tree.Ĭhild nodes There are two types of child nodes: leaf nodes (also called terminal nodes), which This allows hierarchical data to be presented in a compact, yet expandable form. In this case, the individual files are subordinate to the directory that contains them.īranches can be expanded or collapsed on demand by the user. JavaFX's TreeView presents a hierarchical view of data in a tree-like format.įor example, a tree can be used to display the contents of a file system. Collapsed node A collapsed node is one whose children are hidden. Expanded node An expanded node is one whose children are visible. Path A path contains the node and all its ancestors - that is, its parent, its parent's parent, and so on - all the way back to the root. Leaf node A leaf node is one that doesn't have any children. Sibling nodes Sibling nodes are children of the same parent. Parent node The node immediately above a given node is that node's par ent node.Įvery node except the root node must have one Must have one - and only one - root node.Ĭomponent, you pass the root node to the TreeView constructor.Ĭhild node The nodes that appear immediately below a given node are that node's child nodes. Root node A root node is the starting node for a tree. Objects of any type you wish, including types you create yourself. Here, we need to know a few terms that describe the elements in the tree itself: Outline form, which we refer to as a tree. A tree view is a JavaFX control that displays hierarchical data in
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |