Following example shows how to implement custom TreeCellRenderer to customize JTree rendering.
Creating JTree
public class TreeExampleMain {
public static void main(String[] args) {
Hashtable<?, ?> projectHierarchy =
TradingProjectDataService.instance.getProjectHierarchy();
JTree tree = new JTree(projectHierarchy);
tree.setCellRenderer(new TradingProjectTreeRenderer());
JFrame frame = createFrame();
frame.add(new JScrollPane(tree));
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private static JFrame createFrame() {
JFrame frame = new JFrame("JTree Renderer example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(new Dimension(500, 400));
return frame;
}
}
Creating Model
public enum TradingProjectDataService {
instance;
private final String ROLES[] =
{"Project Manager", "Tech Lead", "Developer", "Scrum Master", "Business Analyst"};
private Hashtable<Object, Object> modules = new Hashtable<>();
TradingProjectDataService() {
addModule("Trading", "Real Time Trading", "Order System");
addModule("Future/Option", "Option Analyzer", "Market Scanning System");
addModule("Fixed Income", "Bond Tool", "Price/Yield Calculator",
"Strategy Evaluator");
}
private void addModule(String module, String... projects) {
for (String project : projects) {
modules.put(module, getProject(module, project));
}
}
private Object getProject(String module, String project) {
Hashtable<Object, Object> projectMap = new Hashtable<>();
projectMap.put(new Project(project), getEmployeesForProject(module, project));
return projectMap;
}
private Object getEmployeesForProject(String module, String project) {
//random example employees, in real app we will get it from backend
ProjectParticipant[] employees = new ProjectParticipant[ROLES.length];
for (int i = 0; i < ROLES.length; i++) {
employees[i] = new ProjectParticipant(RandomUtil.getFullName(), ROLES[i]);
}
return employees;
}
public Hashtable<?, ?> getProjectHierarchy() {
return modules;
}
}
public class ProjectParticipant {
private final String name;
private final String role;
public ProjectParticipant(String name, String role) {
this.name = name;
this.role = role;
}
.............
}
public class Project {
private final String name;
public Project(String name) {
this.name = name;
}
.............
}
Implementing TreeCellRenderer
public class TradingProjectTreeRenderer extends DefaultTreeCellRenderer {
private static final String SPAN_FORMAT = "<span style='color:%s;'>%s</span>";
private final ImageIcon employeeIcon;
public TradingProjectTreeRenderer() {
employeeIcon = new ImageIcon(TradingProjectTreeRenderer.class.getResource("/images/employee.png"));
}
@Override
public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded,
boolean leaf, int row, boolean hasFocus) {
super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);
DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
Object userObject = node.getUserObject();
if (userObject instanceof ProjectParticipant) {
ProjectParticipant pp = (ProjectParticipant) userObject;
String text = String.format(SPAN_FORMAT, "blue", pp.getName());
text += " [" + String.format(SPAN_FORMAT, "orange", pp.getRole()) + "]";
this.setText("<html>" + text + "</html>");
this.setIcon(employeeIcon);
} else if (userObject instanceof Project) {
Project project = (Project) userObject;
String text = String.format(SPAN_FORMAT, "green", project.getName());
this.setText("<html>" + text + "</html>");
} else {
String text = String.format(SPAN_FORMAT, "red", userObject);
this.setText("<html>" + text + "</html>");
}
return this;
}
}
Output
Example ProjectDependencies and Technologies Used:
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