A detailed description of how to create and manage views, editors and perspectives.

1. Creating Views and Editors
A detailed description of how to create and manage views, editors and
perspectives.
Redistribution and other use of this material requires written permission from The RCP Company.
L0001 - 2010-11-27

2. Views and Editors in Eclipse Applications
In any Eclipse Application (RCP or IDE) the
primary user interface is via views and editors
organized in one or more perspectives
2
L0001 - 2010-11-27

3. Basic Eclipse UI Information Model
Workspace
Window
Top-level Menu Page Perspective
Top-level Toolbar
Status Line
Editors Views
Switcher
Local Toolbar Drop-Down Menu
3
L0001 - 2010-11-27

4. Editors and Views
The main functionality of an Eclipse application is handled via editors and
views and the actions provided by these
The use of editors and views is different
 Editors express the state of one or more editor inputs – typically file
resources

Editors have an associated life-cycle
 Views express additional navigational or context-oriented information –
e.g. problems, outline or search – and is usually stateless

Views have no state, only configuration – e.g. colors and column
directions
Editors are explicitly saved whereas views are implicitly saved
Editors and views are grouped together via perspectives
4
L0001 - 2010-11-27

5. Visual Differences between Editors and Views
These are some visual differences between editors and views:
 Editors provide additional actions to the top-level menu and the tool
bar; views do not
 Views have an independent menu bar and tool bar; editors do not
 There are at most one active editor in a perspective; there can be any
number of active views
 The are at most one view of each “type”; there can be any number of
editors
 Editors are all placed in the “editor area”; views are placed in a number
of “view stacks”
Using the Presentation API, the visual difference can be ironed out
5
L0001 - 2010-11-27

6. Sites, Parts and References
Views and Editors are represented in three
different ways in the workbench page:
 The site object (IViewSite and IEditorSite) Site
represents the workbench state that is
specific for a part

Access to the workbench, the
workbench window, and the workbench
page

Access to the ID and name of the part Reference
(from the view or editor extension)

Registration of context menus
 The part object (IViewPart and IEditorPart)
represents the actual part of a site Part

This comes from the developed plug-in
 The reference object (IViewReference and
IEditorReference) represents a reference
to a specific part object

Used to prevent premature activation of
plug-ins
6
L0001 - 2010-11-27

7. Views
The Editor IDE contains views with all sorts of content. Some relevant
examples are:
 A table with items: Problems
 A styled text: Javadoc
 A big (virtual) tree: Package Explorer
 Using the Forms UI: Properties (depends on the current editor)
 A graph: Metrics
 A view with content supplied by the editor: Outline
 Tables and trees with sorting and filtering: Problems and Outline
If in doubt about how to implement a specify feature, always have a look at
the views from the IDE. Although these sometimes can seem overly
complicated, they can provide good inspiration.
7
L0001 - 2010-11-27

8. Adding a View
Views are defined via the extension point org.eclipse.ui.views/view
 Has id, name, class, category, icon, fastViewWidthRatio, allowMultiple,
restorable and description (a sub-element)
 Most attributes are optional
<extension point="org.eclipse.ui.views">
<view
category="com.rcpcompany.cexx.viewCategories.Main"
class="com.rcpcompany.cexx.views.ContactTableView"
id="com.rcpcompany.cexx.views.ContactTableView"
name="Contact Table"
restorable="true">
<description>
This view contains a simple table with all defined contacts along with a filter.
</description>
</view>
</extension>
8
L0001 - 2010-11-27

9. View Life Cycle
Before the view is shown
 init(IViewSite) or init(IViewSite, IMemento): marks the start of the view.
The second version is called for views that have saved a memento
 createPartControl(Composite): Creates the visual content of the view
 setFocus(): Sets the initial focus of the view
When the view is closed
 saveState(IMemento): Saves the state of the view in a memento
 dispose(): Disposes all resources – especially images and fonts
9
L0001 - 2010-11-27

10. Standard Views (RCP only)
The platform contains a number of standard views that can be added to an
RCP application via plugin.xml
For example, to add the Progress view, use:
<extension
point="org.eclipse.ui.views">
<view
class="org.eclipse.ui.ExtensionFactory:progressView"
id="com.rcpcompany.gir.application.views.progress"
name="Progress"/>
</extension>
10
L0001 - 2010-11-27

11. Editors
Content
 Text – e.g. a programming language
 Graphical – e.g. a model or an XML file
 Form – e.g. an XML file or a configuration
file
 A combination – e.g. the plugin.xml editor
11
L0001 - 2010-11-27

12. Editors
Interface more complicated than for views, with many more mandatory
methods
 Saving editor content (ISaveablePart)
 Introduces IEditorInput
12
L0001 - 2010-11-27

13. Editor Input
The subject of an editor is specified via an IEditorInput
 Simple interface:
public interface IEditorInput extends IAdaptable {
public boolean exists();
public ImageDescriptor getImageDescriptor();
public String getName();
public IPersistableElement getPersistable();
public String getToolTipText();
}
 Typically a file based on the resource API
 But can be anything – specialized as

IPathEditorInput: Local file system resource

IFileEditorInput: Resource API-based resource

IStorageEditorInput: Storage-based resource – any sequence of bytes
Subclass EditorInput for your own new editor inputs
13
L0001 - 2010-11-27

14. Editor Life Cycle
Before the view is shown
 init(IEditorSite, IEditorInput): marks the start of the editor
 createPartControl(Composite): Creates the visual content of the editor
 setFocus(): Sets the initial focus of the editor
When the editor is closed
 isDirty() and isSaveAsAllowed(): Returns whether saving is needed or
indeed allowed

Used by workbench to determine whether exit is allowed
 doSave(IProgressMonitor) or doSaveAs(): Saves the state of the editor
 dispose(): Disposes all resources – especially images and fonts
14
L0001 - 2010-11-27

15. Lab Exercise
Create a number of views using the UI designer
 If you use the Visual Designer, then start Eclipse 3.2 with its own
workspace and import the existing plug-ins!
15
L0001 - 2010-11-27

16. Saving State (IMemento)
When the workbench closes, all state is saved – including all workbench-related
state
When the workbench is reopened, all state is re-read
State saved in an IMemento
 Hierarchical structure
 Normally XML based
 Data can be

Strings, integers or floats

Text blocks
The view life cycle explicitly handles state
 init(IViewSite, IMemento)
 saveState(IMemento)
Saved as file in the local configuration directory
 Can be saved anywhere
 Workbench reads file workbench.xml
16
L0001 - 2010-11-27

17. Saving State (IMemento)
The IMemento interface has three groups of operations:
 Operations to get or create a child context
 Operations to get or set the values of a context
 A few operations to handle the IDs
public interface IMemento {
public IMemento createChild(String type);
public IMemento createChild(String type, String id);
public IMemento getChild(String type);
public IMemento[] getChildren(String type);
public Float getFloat(String key);
public String getID();
public Integer getInteger(String key);
public String getString(String key);
public String getTextData();
public void putFloat(String key, float value);
public void putInteger(String key, int value);
public void putMemento(IMemento memento);
public void putString(String key, String value);
public void putTextData(String data);
}
17
L0001 - 2010-11-27

18. Saving State in Views and Editors
The view life cycle explicitly handles state
 init(IViewSite, IMemento)

Will be null the first time!
 saveState(IMemento)
 Because views are shared between perspectives, init and saveState will
only be called once per WorkbenchWindow!
In Eclipse 3.3 an editor can also save state
 Must implement IPersistableEditor

restoreState(IMemento)

saveState(IMemento)
18
L0001 - 2010-11-27

19. Lab Exercise
Save and restore the content of the first text field of the first view using
IMemento:
 In WorkbenchAdvisor.preStartup() use
getWorkbenchConfigurer().setSaveAndRestore(true) to enable saved
state (RCP only)
19
L0001 - 2010-11-27

20. Perspectives
A perspective is a description of a number of user interface elements that is
used to perform a specific task
 Whether or not an editor is used
 A specific type of resources that will be shown in the navigator (if used)
 A specific set of views that is used in the perspective
 A specific set of shortcuts to be added to certain menus

Wizards to be shown at the top of the “File” → “New…” menu

Views to be shown at the top of the “Window” → “Show View” menu

Perspectives shown at the top of the perspective switcher
 A specific set of action sets to be added to the top-level menu and tool
bar
A perspective also specifies the layout of the editors and the associated
views using a “slice” system
Additions can be made to a perspective using the perspectiveExtensions
extension point
20
L0001 - 2010-11-27

21. Standard Perspectives
The Eclipse IDE includes a large number of perspectives that correspond to
the many tasks that must be performed in a development environment. For
example:
 Java
 Debug
 Team
 CVS Repository
21
L0001 - 2010-11-27

22. Perspective Implementation
Perspective is a specific layout and views and editors within a Workbench
window
Workspace
Window
Top-level Menu Page Perspective
Top-level Toolbar
Status Line
Editors Views
Switcher
Local Toolbar Drop-Down Menu
22
L0001 - 2010-11-27

23. Adding a New Perspective
A new perspective can easily be added using
the extensions page for the plugin.xml file
 Add a new extension with the name
“org.eclipse.ui.perspectives”
 Select the new line and add a
“New”→”perspective” using the context
menu
 Specify ID, name and factory class
 Click on the “class” link to create the new
View class automatically
23
L0001 - 2010-11-27

24. Designing Perspectives
Nearly any layout with an editor (optional) and zero, one or more views can
be designed using addView(…)
The method is rather simple:
 You start with the editor area
 You then add one new view at a time
 Each time, you divide an already placed view according to an edge (TOP,
RIGHT, BOTTOM, or LEFT) and a percentage (in the range [0.05; 0.95])
Thus addView("view2", IPageLayout.LEFT, 0.4f, "view1") means
 Find the already placed view view1
 Place view2 to the LEFT of view1
 Assign 40% of the original area of view1 to view2
24
L0001 - 2010-11-27

25. Designing Perspectives
1
2
4
Some layouts cannot be created this way – for
example, this “ wheel” layout 3
25
L0001 - 2010-11-27

26. Designing Perspectives
An Example
The parts of layout (the editor and the four views) are represented by the
rectangles
The numbers refers to the next start of the line to be executed
Editor
3 Area
4 5 View1
View2 View4 View2
6 View2 View1 7 View1 8 View1
View3 View3
public void createInitialLayout(IPageLayout layout) {
final String area = layout.getEditorArea();
layout.setEditorAreaVisible(false);
layout.addView("com.rcpcompany.cex.view1", IPageLayout.LEFT, 1.0f, area);
layout.addView("com.rcpcompany.cex.view2", IPageLayout.LEFT, 0.666f, "com.rcpcompany.cex.view1");
layout.addView("com.rcpcompany.cex.view3", IPageLayout.BOTTOM, 0.75f, "com.rcpcompany.cex.view2");
layout.addView("com.rcpcompany.cex.view4", IPageLayout.LEFT, 0.5f, "com.rcpcompany.cex.view2");
}
26
L0001 - 2010-11-27

27. Designing Perspectives
Views can be added to a designated spot in a number of ways
 As a normal view with tab using addView(…)
 As a view with no tab using addStandaloneView(…)
 As a stack or folder using createFolder(…)
 As a fast view using addFastView(…)
Views can also be added as a placeholder for a future view using
addPlaceholder(…) or createFolderPlaceholder(…)
The editor area has ID org.eclipse.ui.editorss (with ss!)
Views can be set un-closeable or un-moveable via getViewLayout(id)
See IPageLayout for more information
27
L0001 - 2010-11-27

28. Extending an Existing Perspective
Used when extending an existing perspective
with information from a new (usually
independent) plug-in
 E.g. adding a new profile view to the Java
perspective
Using extension point
org.eclipse.ui.perspectiveExtensions
 Specify the target perspective ID
 Can add fast views, action set, shortcuts
 Cannot hide or show the editor
28
L0001 - 2010-11-27

29. Lab Exercise
Implement the following perspective using four views via a Java class
 You make the perspective switcher visible in the
WorkbenchWindowAdvisor.preWindowOpen() (RCP Only):
configurer.setShowPerspectiveBar(true)
Then re-implement the layout in a new perspective using the
perspectiveExtensions extension point
 Or just add a new view to the old existing perspective
Later possibly move view3 to a fast view
Make view1 not moveable in both perspectives
Add the new perspective as a shortcut in the old perspective – using
perspectiveExtensions
Stack with View2
and View 4 View1
View3
29
L0001 - 2010-11-27

30. Lab Exercise
Implement the following perspective using four views
Stack with View2
and View 4 Editor
View1
Area
View3
Add one of the above views to the existing Resource perspective using the
perspectiveExtensions extension point
 The ID of the Resource perspective is org.eclipse.ui.resourcePerspective
 The ID of the Task view is org.eclipse.ui.views.TaskList
30
L0001 - 2010-11-27

31. How to open editors, views and perspectives
Perspectives
 IWorkbenchWindow.openPage(String perspectiveId, IAdaptable input)
Editors
 IDE.openEditor(IWorkbenchPage page, IFile file)

One of a large number of methods
 IWorkbenchPage.findEditor(IFile file)
Views
 IWorkbenchPage.showView(String id)

Will open the view in the site according to the perspective definition
31
L0001 - 2010-11-27

32. More Information
“Using Perspectives in the Eclipse UI”
 http://www.eclipse.org/resources/resource.php?id=232
Visual Editor Project
 http://www.eclipse.org/vep/WebContent/main.php
Advanced workbench concepts from Eclipse Help
 http://help.eclipse.org/help32/index.jsp?topic=/
org.eclipse.platform.doc.isv/guide/wrkAdv.htm
“Code Access Guide to Eclipse 3.4”
 http://www.eclipse.org/resources/resource.php?id=428

Among other things an introduction to the PDE Spy.
32
L0001 - 2010-11-27