gwt handling events in cell of cellTree - gwt

Question

i want to handle double click event in a cell of a cellTree but i can't make it work.
Any idea?
Thanks.
if(((Node) value).getNodeType().equals(NodeTypes.Folder))
{
ListDataProvider<Node> dataProvider = new ListDataProvider<Node>(((Node) value).getChildNode());
Cell<Node> cell = new AbstractCell<Node>("dblclick")
{
#Override
public void render(Context context, Node value, SafeHtmlBuilder sb)
{
if (value != null) { sb.appendEscaped(value.getNodeName()); }
}
#Override
public void onBrowserEvent(Context context, Element parent, Node value,
NativeEvent event, ValueUpdater<Node> valueUpdater)
{
if (value == null) { return; }
super.onBrowserEvent(context, parent, value, event, valueUpdater);
if ("dblclick".equals(event))
{
ControllerPqm.getInstance().advise(ControllerPqm.ADVISE_ERROR, "Chick");
}
}
};
return new DefaultNodeInfo<Node>(dataProvider, cell);
}

Answer 1

You have to extend some other Widget and sink the DoubleClick event in the constructor:
sinkEvents(Event.ONCLICK | Event.ONDBLCLICK);
and then proceed to write code to handle the sinked events. Be aware that double click has issues in Linux-version of some browsers - it tends to fire the single click event multiple times as well in linux versions, and in some older mac/win versions.
public void onBrowserEvent(Event event)
{
switch (DOM.eventGetType(event))
{
case Event.ONCLICK:
// your handler code here
break;
case Event.ONDBLCLICK:
// your handler code here
break;
}
}
Ideally in your case, this code should go in the toplevel NodeTree class itself (or something that extends a Widget), on double click it will find the node that got double-clicked and do something based on it.

Answer 2

You must compare the event's type property:
"dblclick".equals(event.getType())

Answer 3

Try this :
public class MyMenuItem {
private String name;
public MyMenuItem(String name) {
super();
this.name = name;
list = new ArrayList<MyMenuItem>();
}
//...
public boolean hasChildrens() {
return list.size()>0;
}
}
public class MyTreeModel implements TreeViewModel {
ArrayList<MyMenuItem> all;
public MyTreeModel() {
all = new ArrayList<MyMenuItem>();
//Default items
all.add(... //fill
}
#Override
public <T> NodeInfo<?> getNodeInfo(T value) {
ListDataProvider<MyMenuItem> dataProvider;
if (value == null) { // root
dataProvider = new ListDataProvider<MyMenuItem>(all);
} else {
dataProvider = new ListDataProvider<MyMenuItem>(((MyMenuItem) value).getList());
}
Cell<MyMenuItem> cell = new MyCell(); //my Cell with dblclick event
return new DefaultNodeInfo<MyMenuItem>(dataProvider, cell);
}
#Override
public boolean isLeaf(Object value) {
if (value instanceof MyMenuItem) {
MyMenuItem t = (MyMenuItem) value;
if (!t.hasChildrens())
return true;
return false;
}
return false;
}
}
Also Cell class:
private static class MyCell extends AbstractCell<MyMenuItem> {
public MyCell() {
super("keydown","dblclick"); //click?
}
#Override
public void onBrowserEvent(Context context, Element parent, MyMenuItem value,
NativeEvent event, ValueUpdater<MyMenuItem> valueUpdater) {
// Check that the value is not null.
if (value == null) {
return;
}
super.onBrowserEvent(context, parent, value, event, valueUpdater);
if ("dblclick".equals(event.getType())) {
this.onEnterKeyDown(context, parent, value, event, valueUpdater);
}
}
#Override
public void render(Context context, MyMenuItem value, SafeHtmlBuilder sb) {
if (value == null) {
return;
}
sb.appendEscaped(value.getName());
}
#Override
protected void onEnterKeyDown(Context context, Element parent,
MyMenuItem value, NativeEvent event, ValueUpdater<MyMenuItem> valueUpdater) {
Window.alert("You clicked "+event.getType()+" " + value.getName());
}
}
`
In the module:
treeModel = new MyTreeModel();
CellTree tree = new CellTree(treeModel,null);
tree.setKeyboardSelectionPolicy(KeyboardSelectionPolicy.ENABLED);
TreeNode rootNode = tree.getRootTreeNode();
TreeNode firstPlaylist = rootNode.setChildOpen(0, true);
//...
verticalPanelWest.add(tree);

Answer 4

If you wand to consume a browserevent in your Cell you need to tell what are the events to be consumed.
Shows example
public class OrderCell extends AbstractCell<Order> {
public OrderCell() {
super("mousedown","mouseover","mouseup","mousemove");
}
#Override
public void onBrowserEvent(com.google.gwt.cell.client.Cell.Context context,
Element parent, Order value, NativeEvent event,
ValueUpdater<Order> valueUpdater) {
System.out.print("event fired");
}