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Explorer API - NetBeans API Javadoc (Current Development Version)
Javadoc
The basic management of the Explorer resides inorg.openide.explorer.
Classes pertaining to the Property Sheet (which displays properties of
explored nodes) may be found in
org.openide.explorer.propertysheet.
A set of standard Explorer Views is available in
org.openide.explorer.view.
Contents
Explorer API
Overview of the Explorer
Explorer views are UI components which render nodes - the most prominent in NetBeans being the Project and Files tabs on the left side of the main window. The Explorer API provides UI components to render nodes in trees, lists, combo boxes, menus, tree tables. These components handle things like cut/copy/paste, drag and drop, displaying popup menus for nodes, which contain the actions the clicked node provides fromgetActions().
The Explorer and Nodes
An Explorer view is solely a user-interface component: it has no particular knowledge of what it is displaying. Rather, it provides the physical user interface for a hierarchy of Nodes, as described in the Nodes API.A given Explorer view instance will be some visual component (such as a Swing panel) displaying some representation of a Node and its children. The topmost node being displayed is said to be the root of the Explorer.
The API permits you to use the prebuilt views, and also to create your own if you need to.
Using the Explorer API
It is rather easy to use the Explorer API to just display an Explorer window of some type, browsing some set of nodes.Displaying a new Explorer window
Probably the easiest way to show an Explorer window is just to callNodeOperation.explore(...).
This will simply show a node and its subtree (if any) in a new window
using the normal tree-style Explorer view. It does not permit any
customization of the UI, however - it creates a standard window with
the usual buttons, etc.
If you want to use a special view, it is first necessary to understand the structure of a live Explorer instance:
- There is a topmost container, an AWT/Swing container
component of any sort, which must implement
ExplorerManager.Provider. Often in NetBeans it will be a subclass of TopComponent. This topmost container does not really do anything; it just makes sure that anExplorerManagercan be found by its children. Follow the instructions inExplorerUtils, to create such a panel. The container that implements ExplorerManager.Provider may contain non-Explorer components - add whatever components you like to it, set layout appropriately. When an Explorer view is added as a descendant of this panel, it will find this panel by searching the component hierarchy.ExplorerManageritself handles the control of the Explorer view or views it is attached to. It provides the external interface by which the selection of nodes, e.g., can be examined or set, and permits multiple views to be synchronized (for example, creating a master/detail view is very easy). - Usually, actions provided by
ExplorerUtils, will be attached to the component to make sure they are correctly enabled or disabled according to the current node selection. Follow the example inExplorerUtils. - Most importantly, the Explorer views themselves are added as
(possibly indirect) children to the topmost component. You do
not need to do anything special to connect the views to the
manager or to one another; when an explorer view is added to a container,
it will find the nearest ExplorerManager in the component hierarchy
(by searching for a parent component that implements ExplorerManager.Provider).
Once you have created an Explorer component, your code will not typically interact directly with it - rather it will call methods on its ExplorerManager to set selection, etc.
- Lastly you'll call ExplorerManager.setRootContext to actually set what node the view will be displaying.
org.openide.explorer.view
contains a number of prebuilt views which you may use. Of special note
are the
BeanTreeView,
which is the standard tree view used to implement the Explorer window
proper;
and
MenuView,
which is of interest because it actually implements a view using popup
menus, rather than a static display. The best way to familiarize
yourself with the standard views, and to test any custom view you
might build, is probably to create an ExplorerPanel which
adds some or all of them; the views will be automatically
synchronized, which will be helpful in understanding how they behave.
Displaying a Property Sheet
Adding a Property Sheet (which just shows the properties of the selected node(s), and may allow editing of those properties) is quite easy - all you need to do is to add aPropertySheetView
to the container. It is an Explorer view which does not actually
display any nodes, but rather displays a list of properties for the
node or nodes which are selected according to the ExplorerManager.
Since views by default will share the same manager if they are added to the same manager-providing container, just adding a regular Explorer view and a Property Sheet to the same container will result in the Property Sheet being sensitive to the node selection in the regular view, which is usually the desired effect.
Aspects of Nodes affecting the Explorer
Particular Explorer views are of course free to display the node hierarchy any way they wish; however, there are a few common aspects of the represented nodes which are likely to be visually mirrored:- The node's display name and short description ought to be used by views to display the node and provide (e.g.) tool tips.
- The icon is used in most views alongside the display name. Non-leaf nodes upon expansion will show the opened icon.
- Some or all of the node's
children
are typically displayed (except of course if it is a
leaf).
Normally they will be in the same order as
the node itself
specifies,
though a view might provide special display characteristics for
certain children lists such as
Children.Keys. Generally nodes may allow their children to be reordered. Node.getActions(),Node.getContextActions(),Node.getDefaultAction(),Node.getContextMenu(), etc. are typically used to build an event-handling system for the visual representation of the nodes.- Standard actions are generally enabled on nodes in the Explorer,
so that
Node.hasCustomizer(),Node.getLookup().lookup(...),Node.getNewTypes(),Node.getPasteTypes(...), and so on affect other UI components (such as toolbars) which may hold action presenters. Node.getPropertySets()is of course used by the Property Sheet view.- Some views may provide in-place editing commands (not relying on
system actions present in popup menus, e.g.) for moving nodes,
renaming them in place, etc. - these will use the standard node hooks
such as
Node.canRename(),Node.cloneNode(), orNode.clipboardCut().
Customizing the Explorer
Though rarely necessary, the API allows you to create your own Explorer views, as described here.The Property Sheet
Older versions of NetBeans relied heavily on the Property Sheet as a primary element of the user interface. However, this turned out not to be terribly user-friendly, and the Property Sheet is used considerably less today (it is no longer even displayed by default on startup).Consider providing a custom UI where possible, rather than relying on the user having the Property Sheet visible to work with your module.
Customizing the Property Sheet
The Property Sheet displays property sets in expandable
categories inside a single tree, rather than using tabs as the old
Property Sheet did. However, there are some cases where tabs are
desirable. A mechanism exists by which an instance of
A number of system properties, UI manager keys and such also affect
the way Property Sheets are displayed and behave. A complete reference
can be found here.
Node.PropertySet can specify that it should be displayed in
a tab: It must return an internationalized string from
PropertySet.getValue("tabName"). If multiple
property sets belonging to a single node specify the same tab name
in this manner, all of them will be included on a tab with the specified
name*.
* Note that for this functionality to function properly, the NetBeans Window System must be installed. Further information on how to work use this functionality in a stand-alone application can be found here.
Property Editors
The NetBeans core installs a variety of property editors for standard JDK classes and some NetBeans classes. A number of these can have their behavior altered by passing "hints" fromNode.Property or
PropertyDescriptor. This is described in detail
here.
Built on May 28 2007. | Portions Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.