How to make child Tree Items checked/un-checked if parent Tree was made checked/un-checked

Question

I'm having a Check-box Tree View structure, consisting of parent and child nodes.

I want to make all the child nodes [of the parent node] appear as checked if parent Tree is checked. Similarly, if parent Tree is unchecked then its childrens should be unchecked.

Answer 1

The best way to achieve this would be using the JFace CheckboxTreeViewer as it has the following predefined methods to simplify the task.

1. setSubtreeChecked - Sets the child elements checked on selecting the parent node

2. getCheckedElements - Gets all the checked tree elements

   final CheckboxTreeViewer treeViewer = new CheckboxTreeViewer(parent);
   
   // When user checks a checkbox in the tree, check all its children
   treeViewer.addCheckStateListener(new ICheckStateListener() {
   public void checkStateChanged(CheckStateChangedEvent event) {
       // If the item is checked . . .
       if (event.getChecked()) {
         // . . . check all its children
         treeViewer.setSubtreeChecked(event.getElement(), true);
       }
     }
   });
   
   // Get the selected elements from the tree
   Object[] actuallyChecked = treeViewer.getCheckedElements();