Custom GWT Tree table with TreeItem and FlexTable - gwt

Question

GWT does not contain TreeTable but my project requirement with tree table. so I created it by using Tree and FlexTable.
Here Bean class: Item
class Item
{
ItemType itemType; //Parent,Child Enum type
long parentId;
long amount;
String itemName;
String qty;
String rate;
//Setter / Getter Methods
}
This is custom TreeItem class which has relation between parent Item & Child Item. I have Created one row By using TreeItemNode.
public class TreeItemNode extends TreeItem {
private FlexTable table; //this will use to access child
private FlexTable parentTable; //This will use to access parent of particular child.
//This constructor create parent node
public TreeItemNode(FlexTable parentTable) {
setWidget(parentTable);
this.parentTable=parentTable;
setState(true);
}
//The method used to add Child items in parent
public TreeItem addItem(Widget widget) {
this.table=(FlexTable) widget;
TreeItem ret = new TreeItem(widget);
addItem(ret);
return ret;
}
}
Using Item List, This method is creating the tree which has parent and child node relations.
class CustomTreeTable extends Tree
{
public void createTreeTable() {
//This map store parent id and tree item object for letter fetch the parent node and add child node in it
treeItemMap = new HashMap<Long, BOQTreeItem>();
for (Item item : itemList) {
if (item.getParentItemId() == 0) {
//Create new parent node
TreeItemNode itemTreeItem = new TreeItemNode(addChildItem(item,
new FlexTable(), true),
"gwt-TreeNode");
treeItemMap.put(item.getId(), treeItem);
addItem(itemTreeItem);
} else {
//Add child node
if (treeItemMap.containsKey(item.getParentItemId())
&& treeItemMap.get(item.getParentItemId()) != null) {
FlexTable dataFlextable = treeItemMap.get(
item.getParentItemId()).getTable();
if (dataFlextable == null) {
dataFlextable = new FlexTable();
treeItemMap.get(item.getParentItemId()).setTable(
dataFlextable);
}
FlexTable treeTable = addChildItem(item, dataFlextable,
false);
treeItemMap.get(item.getParentItemId()).addItem(treeTable);
}
}
}
}
}
Using this my table is as below. + is my tree node open/ close like:
ItemName qty rate amount
+ item1 11 1 11 //parent item
---------------------------
- item2 11 2 22
--------------------------------
SubItemName qty rate amount //child item
subItem1 5 2 10
subItem2 8 5 40
------------------------------------
The problem is when I want calculate qty* rate in one raw (child item) than I can do using row index but if I want to do calculate all the child item & show in parent row. then logic become so complex. so I just want to know the logic which I implemented like store the instance in map and managed. is it proper? I am going in right direction or wrong.

Answer 1

Maybe using a DataGrid Widget will be simpler for what you are trying to achieve.
Look at the GWT ShowCase : here
On the DataGrid, you have childs under parent row displaying when you click on ShowFriends link.
Hope it helps. :)