Class Viewer
- All Implemented Interfaces:
IInputProvider
,IInputSelectionProvider
,ISelectionProvider
- Direct Known Subclasses:
AbstractViewer
,ContentViewer
,TextViewer
A viewer can be created as an adapter on a pre-existing control (e.g.,
creating a ListViewer
on an existing List
control).
All viewers also provide a convenience constructor for creating the control.
Implementing a concrete viewer typically involves the following steps:
- create SWT controls for viewer (in constructor) (optional)
- initialize SWT controls from input (inputChanged)
- define viewer-specific update methods
- support selections (
setSelection
,getSelection
)
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Field Summary
Modifier and TypeFieldDescriptionprotected static final String
Unique key for associating element data with widgets. -
Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionvoid
addHelpListener
(HelpListener listener) Adds a listener for help requests in this viewer.void
Adds a listener for selection changes in this selection provider.protected void
fireHelpRequested
(HelpEvent event) Notifies any help listeners that help has been requested.protected void
Notifies any selection changed listeners that the viewer's selection has changed.abstract Control
Returns the primary control associated with this viewer.Returns the value of the property with the given name, ornull
if the property is not found.abstract Object
getInput()
Returns the input.abstract ISelection
Returns the current selection for this provider.protected void
handleHelpRequest
(HelpEvent event) Handles a help request from the underlying SWT control.protected void
inputChanged
(Object input, Object oldInput) Internal hook method called when the input to this viewer is initially set or subsequently changed.abstract void
refresh()
Refreshes this viewer completely with information freshly obtained from this viewer's model.void
removeHelpListener
(HelpListener listener) Removes the given help listener from this viewer.void
Removes the given selection change listener from this selection provider.scrollDown
(int x, int y) Scrolls the viewer's control down by one item from the given display-relative coordinates.scrollUp
(int x, int y) Scrolls the viewer's control up by one item from the given display-relative coordinates.void
Sets the value of the property with the given name to the given value, or tonull
if the property is to be removed.abstract void
Sets or clears the input for this viewer.void
setSelection
(ISelection selection) The viewer implementation of thisISelectionProvider
method make the new selection for this viewer without making it visible.abstract void
setSelection
(ISelection selection, boolean reveal) Sets a new selection for this viewer and optionally makes it visible.
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Field Details
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WIDGET_DATA_KEY
Unique key for associating element data with widgets.
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Constructor Details
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Viewer
protected Viewer()Creates a new viewer.
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Method Details
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addHelpListener
Adds a listener for help requests in this viewer. Has no effect if an identical listener is already registered.- Parameters:
listener
- a help listener
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addSelectionChangedListener
Description copied from interface:ISelectionProvider
Adds a listener for selection changes in this selection provider. Has no effect if an identical listener is already registered.- Specified by:
addSelectionChangedListener
in interfaceISelectionProvider
- Parameters:
listener
- a selection changed listener
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fireHelpRequested
Notifies any help listeners that help has been requested. Only listeners registered at the time this method is called are notified.- Parameters:
event
- a help event- See Also:
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fireSelectionChanged
Notifies any selection changed listeners that the viewer's selection has changed. Only listeners registered at the time this method is called are notified.- Parameters:
event
- a selection changed event- See Also:
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getControl
Returns the primary control associated with this viewer.- Returns:
- the SWT control which displays this viewer's content
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getData
Returns the value of the property with the given name, ornull
if the property is not found.The default implementation performs a (linear) search of an internal table. Overriding this method is generally not required if the number of different keys is small. If a more efficient representation of a viewer's properties is required, override both
getData
andsetData
.- Parameters:
key
- the property name- Returns:
- the property value, or
null
if the property is not found
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getInput
Description copied from interface:IInputProvider
Returns the input.- Specified by:
getInput
in interfaceIInputProvider
- Returns:
- the input object
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getSelection
Description copied from interface:ISelectionProvider
Returns the current selection for this provider.- Specified by:
getSelection
in interfaceISelectionProvider
- Returns:
- the current selection
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handleHelpRequest
Handles a help request from the underlying SWT control. The default behavior is to fire a help request, with the event's data modified to hold this viewer.- Parameters:
event
- the event
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inputChanged
Internal hook method called when the input to this viewer is initially set or subsequently changed.The default implementation does nothing. Subclassers may override this method to do something when a viewer's input is set. A typical use is populate the viewer.
- Parameters:
input
- the new input of this viewer, ornull
if noneoldInput
- the old input element ornull
if there was previously no input
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refresh
public abstract void refresh()Refreshes this viewer completely with information freshly obtained from this viewer's model. -
removeHelpListener
Removes the given help listener from this viewer. Has no effect if an identical listener is not registered.- Parameters:
listener
- a help listener
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removeSelectionChangedListener
Description copied from interface:ISelectionProvider
Removes the given selection change listener from this selection provider. Has no effect if an identical listener is not registered.- Specified by:
removeSelectionChangedListener
in interfaceISelectionProvider
- Parameters:
listener
- a selection changed listener
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scrollDown
Scrolls the viewer's control down by one item from the given display-relative coordinates. Returns the newly revealed Item, ornull
if no scrolling occurred or if the viewer doesn't represent an item-based widget.- Parameters:
x
- horizontal coordinatey
- vertical coordinate- Returns:
- the item scrolled down to
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scrollUp
Scrolls the viewer's control up by one item from the given display-relative coordinates. Returns the newly revealed Item, ornull
if no scrolling occurred or if the viewer doesn't represent an item-based widget.- Parameters:
x
- horizontal coordinatey
- vertical coordinate- Returns:
- the item scrolled up to
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setData
Sets the value of the property with the given name to the given value, or tonull
if the property is to be removed. If this viewer has such a property, its value is replaced; otherwise a new property is added.The default implementation records properties in an internal table which is searched linearly. Overriding this method is generally not required if the number of different keys is small. If a more efficient representation of a viewer's properties is required, override both
getData
andsetData
.- Parameters:
key
- the property namevalue
- the property value, ornull
if the property is not found
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setInput
Sets or clears the input for this viewer.- Parameters:
input
- the input of this viewer, ornull
if none
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setSelection
The viewer implementation of thisISelectionProvider
method make the new selection for this viewer without making it visible.This method is equivalent to
setSelection(selection,false)
.Note that some implementations may not be able to set the selection without also revealing it, for example (as of 3.3) TreeViewer.
- Specified by:
setSelection
in interfaceISelectionProvider
- Parameters:
selection
- the new selection
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setSelection
Sets a new selection for this viewer and optionally makes it visible.Subclasses must implement this method.
- Parameters:
selection
- the new selectionreveal
-true
if the selection is to be made visible, andfalse
otherwise
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