Refer to data fields in TreeView Type other than String - javafx

Question

I have used the sample Tree User interface on the JAVA FX 2 site and changed the type from String to PayString and all seems to work well. My next step is in the setCellFactory 'TextFieldTreeCellImpl' I need to assign a different context menu to the cells depending upon the value of PayString.level an integer.
How do I reference the value of the data fields associated with the current cell.
Below are the two source files code in packages treeviewsample. The position I need the data is marked with +++++++++++++++++++++++++ for ease of finding.
`/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package treeviewsample;
import java.util.Arrays;
import java.util.List;
import javafx.application.Application;
import javafx.beans.property.IntegerProperty;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.TextField;
import javafx.scene.control.TreeCell;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.util.Callback;
import javafx.beans.property.SimpleStringProperty;
import javafx.scene.control.ContextMenu;
import javafx.scene.control.MenuItem;
import javafx.scene.layout.VBox;
public class TreeViewSample extends Application {
private final Node rootIcon;
private final Image depIcon;
List<Employee> employees = Arrays.<Employee>asList(
new Employee(1, "Ethan Williams", "Sales Department"),
new Employee(2, "Emma Jones", "Sales Department"),
new Employee(3, "Michael Brown", "Sales Department"),
new Employee(4, "Anna Black", "Sales Department"),
new Employee(5, "Rodger York", "Sales Department"),
new Employee(6, "Susan Collins", "Sales Department"),
new Employee(7, "Mike Graham", "IT Support"),
new Employee(8, "Judy Mayer", "IT Support"),
new Employee(9, "Gregory Smith", "IT Support"),
new Employee(10, "Jacob Smith", "Accounts Department"),
new Employee(11, "Isabella Johnson", "Accounts Department"));
TreeItem<PayString> rootNode;
Integer next;
public static void main(String[] args) {
Application.launch(args);
}
public TreeViewSample() {
this.next = 12;
this.depIcon = new Image(getClass().getResourceAsStream("department.png"));
this.rootIcon = new ImageView(new Image(getClass().getResourceAsStream("root.png")));
this.rootNode = new TreeItem<>(new PayString ("MyCompany Human Resources", 0,0), rootIcon);
}
#Override
public void start(Stage stage) {
rootNode.setExpanded(true);
for (Employee employee : employees) {
TreeItem<PayString> empLeaf = new TreeItem<>(new PayString(employee.getName(),2,employee.getId()));
boolean found = false;
for (TreeItem<PayString> depNode : rootNode.getChildren()) {
if (depNode.getValue().toString().contentEquals(employee.getDepartment())){
depNode.getChildren().add(empLeaf);
found = true;
break;
}
}
if (!found) {
TreeItem depNode = new TreeItem<>(new PayString(employee.getDepartment(),1,employee.getId()),
new ImageView(depIcon)
);
rootNode.getChildren().add(depNode);
depNode.getChildren().add(empLeaf);
}
}
stage.setTitle("Tree View Sample");
VBox box = new VBox();
final Scene scene = new Scene(box, 400, 300);
scene.setFill(Color.LIGHTGRAY);
TreeView<PayString> treeView = new TreeView<>(rootNode);
treeView.setEditable(true);
treeView.setCellFactory(new Callback<TreeView<PayString>,TreeCell<PayString>>(){
#Override
public TreeCell<PayString> call(TreeView<PayString> p) {
return new TextFieldTreeCellImpl();
}
});
box.getChildren().add(treeView);
stage.setScene(scene);
stage.show();
}
private final class TextFieldTreeCellImpl extends TreeCell<PayString> {
private TextField textField;
private ContextMenu addMenu = new ContextMenu();
/* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
* This is where I need to be able to extract the values in the current TreeCell<PayString>
* to be able to create the appropriate context menu.
* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
*/
private String curr = getString();
public TextFieldTreeCellImpl() {
TreeItem<PayString> paystring = treeItemProperty().getValue();
MenuItem addMenuItem = new MenuItem("Add Employee");
MenuItem addMenuItem2 = new MenuItem("Add Address");
MenuItem addMenuItem3 = new MenuItem(curr);
addMenu.getItems().add(addMenuItem2);
addMenu.getItems().add(addMenuItem3);
addMenuItem.setOnAction(new EventHandler() {
#Override
public void handle(Event t) {
TreeItem newEmployee =
new TreeItem<>(new PayString ("New Employee",3,next));
next ++;
getTreeItem().getChildren().add(newEmployee);
}
});
}
#Override
public void startEdit() {
super.startEdit();
if (textField == null) {
createTextField();
}
setText(null);
setGraphic(textField);
textField.selectAll();
}
#Override
public void cancelEdit() {
super.cancelEdit();
setText(getString());
setGraphic(getTreeItem().getGraphic());
}
#Override
public void updateItem(PayString item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setText(null);
setGraphic(null);
} else {
if (isEditing()) {
if (textField != null) {
textField.setText(getString());
}
setText(null);
setGraphic(textField);
} else {
setText(getString());
setGraphic(getTreeItem().getGraphic());
if (
!getTreeItem().isLeaf()&&getTreeItem().getParent()!= null
){
setContextMenu(addMenu);
}
}
}
}
private void createTextField() {
textField = new TextField(getString());
textField.setOnKeyReleased(new EventHandler<KeyEvent>() {
#Override
public void handle(KeyEvent t) {
if (t.getCode() == KeyCode.ENTER) {
commitEdit(new PayString (textField.getText(),3,next));
} else if (t.getCode() == KeyCode.ESCAPE) {
cancelEdit();
}
}
});
}
private String getString() {
return getItem() == null ? "" : getItem().toString();
}
}
public static class Employee {
private final SimpleStringProperty name;
private final SimpleStringProperty department;
private final Integer id;
private Employee(Integer id, String name, String department) {
this.name = new SimpleStringProperty(name);
this.department = new SimpleStringProperty(department);
this.id = new Integer(id);
}
public Integer getId() {
return id;
}
public String getName() {
return name.get();
}
public void setName(String fName) {
name.set(fName);
}
public String getDepartment() {
return department.get();
}
public void setDepartment(String fName) {
department.set(fName);
}
}
}
package treeviewsample;
import java.util.Objects;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
/**
*
* #author Len
*/
public class PayString {
private final String description;
private final Integer level;
private final Integer id;
public PayString(String description, Integer level, Integer id) {
this.id = id;
this.level = level;
this.description = description;
}
public int getId() {
return id;
}
public int getLevel() {
return level;
}
public String getDescription() {
return description;
}
#Override
public int hashCode() {
int hash = 7;
return hash;
}
public boolean contentEquals(Object obj) {
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final PayString other = (PayString) obj;
if (!Objects.equals(this.description, other.description)) {
return false;
}
return true;
}
#Override
public String toString() {
return description;
}
}
`

Answer 1

You can always access the current data associated with your cell by calling
PayString value = getTreeItem().getValue()
However there is no 1:1 relationship between a cell and its value. JavaFX creates as many TreeCells it needs to display. It then dynamically assigns them to the underlying data items by calling the method
public void updateItem(PayString item, boolean empty) { ... }
This is where you can set a context menu that depends on the current data item. And there you get the data item passed in as parameter anyway.
At the code position you marked current data item will be null.