Thanks following is the way my application is structured.
I am using ReorderingTreeDNDExample.java but modified it a little bit.
package com.cmt.client.samples.examples.dnd;
import java.util.ArrayList;
import com.cmt.client.model.MediaEntry;
import com.cmt.client.model.MediasetModel;
import com.cmt.client.model.Skeleton;
import com.cmt.client.samples.Examples;
import com.cmt.client.samples.ExamplesModel;
import com.cmt.client.samples.examples.model.Category;
import com.extjs.gxt.ui.client.Registry;
import com.extjs.gxt.ui.client.Style.Scroll;
import com.extjs.gxt.ui.client.binder.TreeBinder;
import com.extjs.gxt.ui.client.data.ModelData;
import com.extjs.gxt.ui.client.data.TreeModel;
import com.extjs.gxt.ui.client.dnd.TreeDragSource;
import com.extjs.gxt.ui.client.dnd.TreeDropTarget;
import com.extjs.gxt.ui.client.dnd.DND.Feedback;
import com.extjs.gxt.ui.client.event.DNDEvent;
import com.extjs.gxt.ui.client.event.DNDListener;
import com.extjs.gxt.ui.client.store.TreeStore;
import com.extjs.gxt.ui.client.widget.LayoutContainer;
import com.extjs.gxt.ui.client.widget.tree.Tree;
import com.extjs.gxt.ui.client.widget.tree.TreeItem;
import com.google.gwt.user.client.Element;
import com.google.gwt.user.client.Window;
public class ReordingTreeDNDExample extends LayoutContainer {
private Tree tree = new Tree();
private TreeStore store;
public Tree getTree()
{
return this.tree;
}
public Tree setTree(Tree tree)
{
return this.tree = tree;
}
@Override
protected void onRender(Element parent, int index) {
super.onRender(parent, index);
LayoutContainer container = new LayoutContainer();
container.setSize(800, 500);
container.setBorders(false);
container.setScrollMode(Scroll.NONE);
setStyleAttribute("margin", "10px");
Skeleton skeleton = new Skeleton();
store = new TreeStore();
TreeModel root = (Skeleton) skeleton;
store.add(root, true);
tree.getStyle().setLeafIconStyle("icon-list");
TreeBinder binder = new TreeBinder(tree, store) {
@Override
public boolean hasChildren(ModelData parent) {
if ("My Files".equals(parent.get("name")) || parent instanceof MediasetModel) {
return true;
}
return super.hasChildren(parent);
}
};
binder.setAutoLoad(true);
binder.setDisplayProperty("name");
binder.init();
tree.getRootItem().getItem(0).setExpanded(true);
tree.getRootItem().getItem(0).setLeaf(false);
tree.setWidth(800);
TreeDragSource source = new TreeDragSource(binder);
source.addDNDListener(new DNDListener() {
@Override
public void dragStart(DNDEvent e) {
TreeItem item = tree.findItem(e.getTarget());
if (item != null && item == tree.getRootItem().getItem(0) && tree.getRootItem().getItemCount() == 1) {
e.doit = false;
e.status.setStatus(false);
return;
}
super.dragStart(e);
}
});
TreeDropTarget target = new TreeDropTarget(binder);
target.setAllowSelfAsSource(true);
target.setFeedback(Feedback.BOTH);
container.add(tree);
add(container);
tree.hide();
}
}
The only difference I have here is Skeleton class, that is pretty much skeleton of the model, creates the structure and lets you add entries in it. In my entry point class, I instantiate an object of this class. And I pass a reference of it to another tree(ContextMenuTree which is left navigation object of my page) in the constructor.
And in that tree on selectionchange event I make async call to get data and try to rebind data to the reordering tree as follows.
/*dragTree is the reference to the reordering tree, tree is contextmenutree which is being built */
TreeBuilder.buildTree(
tree, root);
tree.addListener(Events.SelectionChange, new Listener<TreeEvent>(){
publicvoid handleEvent(TreeEvent be )
{
if(tree.getSelectedItem() != null)
{
if(tree.getSelectedItem().hasChildren() == false)
{
if(dragTree != null)
{
try
{
getMediaset(Integer.parseInt(tree.getSelectedItem().getModel().get("id").toString()));
dragTree.getTree().getRootItem().getItems().get(0).setText(tree.getSelectedItem().getText());
}
catch(Exception ex)
{
Info.display("Error Tree Selection Change", ex.getMessage());
}
com.google.gwt.user.client.Window.alert("To Do: Update Right Panel");
}
else
{
com.google.gwt.user.client.Window.alert("It's pretty much null");
}
}
}
}
}
);
And getMediaset method is as follows.
private
void getMediaset(int playlistId)
{
if (playlistDataSvc == null) {
playlistDataSvc = GWT.create(PlaylistDataService.class);
}
AsyncCallback<ArrayList<Mediaset>> callback = new AsyncCallback<ArrayList<Mediaset>>() {
publicvoid onFailure(Throwable caught) {
// TODO: Do something with errors.
Info.display(
"Problem","Failure RPC call while saving playlist");
}
publicvoid onSuccess(ArrayList<Mediaset> result) {
Tree newTree = new Tree();
TreeStore newStore = new TreeStore();
//removing all elements in the reordering tree
dragTree.getTree().getRootItem().removeAll();
Skeleton skeleton = (Skeleton) new Skeleton();
/* Process result, create skeleton by using data, didn't include not to elobarate the discussion */
try
{
TreeModel treemodel = (Skeleton) skeleton;
newStore =
new TreeStore();
newStore.add(treemodel,true);
TreeBinder binder = new TreeBinder(dragTree.getTree(), newStore);
binder.setAutoLoad(true);
binder.setDisplayProperty("name");
binder.init();
Info.display(
"No Error", "Hatasiz kul olmaz");
}
catch(Exception ex)
{
Info.display("Error", ex.getMessage());
}
dragTree.getTree().show();
}
};
playlistDataSvc.getMediaset(playlistId, callback);
}
If I try to bind the new data to the existing reorderingdndtree object I catch these errors.
Index:0 Size:0
Index:3 Size:0,
if I create a new tree in the eventhandler method and bind the data to it and If I set the reorderingtree's tree to that object, I don't receive an error but I don't see anything on the screen.
And I tested and it looks like I don't have a problem with my model. When I add entries while instantiating the reorderingtree, everything works like a charm but when I try to rebind the tree with new data I experience the problem.
Thanks in advance.