Class Tree
A standard hierarchical tree widget. The tree contains a hierarchy of
TreeItems that the user can
open, close, and select.

CSS Style Rules
- .gwt-Tree { the tree itself }
- .gwt-Tree .gwt-TreeItem { a tree item }
- .gwt-Tree .gwt-TreeItem-selected { a selected tree item }
Example
public class TreeExample implements EntryPoint {
public void onModuleLoad() {
// Create a tree with a few items in it.
TreeItem root = new TreeItem("root");
root.addItem("item0");
root.addItem("item1");
root.addItem("item2");
Tree t = new Tree();
t.addItem(root);
// Add it to the root panel.
RootPanel.get().add(t);
}
}
Constructors
Tree() | Constructs an empty tree. |
Methods
Constructor Detail
Tree
public Tree()
Constructs an empty tree.
Method Detail
addFocusListener
Parameters
- listener
-
addItem
Adds a simple tree item containing the specified text.
Parameters
- itemText
- the text of the item to be added
Return Value
the item that was added
addItem
Adds an item to the root level of this tree.
Parameters
- item
- the item to be added
addKeyboardListener
Parameters
- listener
-
addMouseListener
Parameters
- listener
-
addTreeListener
Adds a listener interface to receive tree events.
Parameters
- listener
- the listener interface to add
ensureSelectedItemVisible
public void ensureSelectedItemVisible()
Ensures that the currently-selected item is visible, opening its parents
and scrolling the tree as necessary.
getImageBase
Gets this tree's default image package.
Return Value
the tree's image package
See Also
setImageBase
getItem
Gets the top-level tree item at the specified index.
Parameters
- index
- the index to be retrieved
Return Value
the item at that index
getItemCount
public int getItemCount()
Gets the number of items contained at the root of this tree.
Return Value
this tree's item count
getSelectedItem
Gets the currently selected item.
Return Value
the selected item
getTabIndex
public int getTabIndex()
moveSelectionDown
public void
moveSelectionDown(
TreeItem sel, boolean dig)
Parameters
- sel
-
- dig
-
moveSelectionUp
public void
moveSelectionUp(
TreeItem sel, boolean climb)
Parameters
- sel
-
- climb
-
onBrowserEvent
public void
onBrowserEvent(
Event event)
Parameters
- event
-
onLoad
protected void onLoad()
This method is called when the widget becomes attached to the browser's
document.
removeFocusListener
Parameters
- listener
-
removeItem
Removes an item from the root level of this tree.
Parameters
- item
- the item to be removed
removeItems
public void removeItems()
Removes all items from the root level of this tree.
removeKeyboardListener
Parameters
- listener
-
removeTreeListener
Removes a previously added listener interface.
Parameters
- listener
- the listener interface to remove
setAccessKey
public void setAccessKey(char key)
Parameters
- key
-
setFocus
public void setFocus(boolean focus)
Parameters
- focus
-
setImageBase
public void
setImageBase(
String baseUrl)
Sets the base URL under which this tree will find its default images. These
images must be named "tree_white.gif", "tree_open.gif", and
"tree_closed.gif".
Parameters
- baseUrl
-
setSelectedItem
public void
setSelectedItem(
TreeItem item)
Selects a specified item.
Parameters
- item
- the item to be selected, or
null
to unselect all
items
setSelectedItem
public void
setSelectedItem(
TreeItem item, boolean fireEvents)
Selects a specified item.
Parameters
- item
- the item to be selected, or
null
to unselect all
items
- fireEvents
-
true
to allow selection events to be fired
setTabIndex
public void setTabIndex(int index)
Parameters
- index
-