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Eclipse Platform
Release 3.0

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org.eclipse.jface.viewers
Class ContentViewer

java.lang.Object
  org.eclipse.jface.viewers.Viewer
      org.eclipse.jface.viewers.ContentViewer

All Implemented Interfaces:

IInputProvider, IInputSelectionProvider, ISelectionProvider

Direct Known Subclasses:

ContentMergeViewer, StructuredViewer

public abstract class ContentViewer

extends Viewer

A content viewer is a model-based adapter on a widget which accesses its model by means of a content provider and a label provider.

A viewer's model consists of elements, represented by objects. A viewer defines and implements generic infrastructure for handling model input, updates, and selections in terms of elements. Input is obtained by querying an IContentProvider which returns elements. The elements themselves are not displayed directly. They are mapped to labels, containing text and/or an image, using the viewer's ILabelProvider.

Implementing a concrete content 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)

Field Summary

Fields inherited from class org.eclipse.jface.viewers.Viewer

WIDGET_DATA_KEY

Constructor Summary

protected

ContentViewer() Creates a content viewer with no input, no content provider, and a default label provider.

Method Summary

IContentProvider	getContentProvider() Returns the content provider used by this viewer, or null if this view does not yet have a content provider.
Object	getInput() The ContentViewer implementation of this IInputProvider method returns the current input of this viewer, or null if none.
IBaseLabelProvider	getLabelProvider() Returns the label provider used by this viewer.
protected void	handleDispose(DisposeEvent event) Handles a dispose event on this viewer's control.
protected void	handleLabelProviderChanged(LabelProviderChangedEvent event) Handles a label provider changed event.
protected void	hookControl(Control control) Adds event listener hooks to the given control.
protected void	labelProviderChanged() Notifies that the label provider has changed.
void	setContentProvider(IContentProvider contentProvider) Sets the content provider used by this viewer.
void	setInput(Object input) The ContentViewer implementation of this Viewer method invokes inputChanged on the content provider and then the inputChanged hook method.
void	setLabelProvider(IBaseLabelProvider labelProvider) Sets the label provider for this viewer.

Methods inherited from class org.eclipse.jface.viewers.Viewer

addHelpListener, addSelectionChangedListener, fireHelpRequested, fireSelectionChanged, getControl, getData, getSelection, handleHelpRequest, inputChanged, refresh, removeHelpListener, removeSelectionChangedListener, scrollDown, scrollUp, setData, setSelection, setSelection

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ContentViewer

protected ContentViewer()

Creates a content viewer with no input, no content provider, and a default label provider.

Method Detail

getContentProvider

public IContentProvider getContentProvider()

Returns the content provider used by this viewer, or null if this view does not yet have a content provider.

The ContentViewer implementation of this method returns the content provider recorded is an internal state variable. Overriding this method is generally not required; however, if overriding in a subclass, super.getContentProvider must be invoked.

Returns:

the content provider, or null if none

getInput

public Object getInput()

The ContentViewer implementation of this IInputProvider method returns the current input of this viewer, or null if none. The viewer's input provides the "model" for the viewer's content.

Specified by:

getInput in interface IInputProvider

Specified by:

getInput in class Viewer

getLabelProvider

public IBaseLabelProvider getLabelProvider()

Returns the label provider used by this viewer.

The ContentViewer implementation of this method returns the label provider recorded in an internal state variable; if none has been set (with setLabelProvider) a SimpleLabelProvider will be created, remembered, and returned. Overriding this method is generally not required; however, if overriding in a subclass, super.getLabelProvider must be invoked.

Returns:

a label provider

handleDispose

protected void handleDispose(DisposeEvent event)

Handles a dispose event on this viewer's control.

The ContentViewer implementation of this method disposes of this viewer's label provider and content provider (if it has one). Subclasses should override this method to perform any additional cleanup of resources; however, overriding methods must invoke super.handleDispose.

Parameters:

event - a dispose event

handleLabelProviderChanged

protected void handleLabelProviderChanged(LabelProviderChangedEvent event)

Handles a label provider changed event.

The ContentViewer implementation of this method calls labelProviderChanged() to cause a complete refresh of the viewer. Subclasses may reimplement or extend.

hookControl

protected void hookControl(Control control)

Adds event listener hooks to the given control.

All subclasses must call this method when their control is first established.

The ContentViewer implementation of this method hooks dispose events for the given control. Subclasses may override if they need to add other control hooks; however, super.hookControl must be invoked.

Parameters:

control - the control

labelProviderChanged

protected void labelProviderChanged()

Notifies that the label provider has changed.

The ContentViewer implementation of this method calls refresh(). Subclasses may reimplement or extend.

setContentProvider

public void setContentProvider(IContentProvider contentProvider)

Sets the content provider used by this viewer.

The ContentViewer implementation of this method records the content provider in an internal state variable. Overriding this method is generally not required; however, if overriding in a subclass, super.setContentProvider must be invoked.

Parameters:

contentProvider - the content provider

See Also:

getContentProvider()

setInput

public void setInput(Object input)

The ContentViewer implementation of this Viewer method invokes inputChanged on the content provider and then the inputChanged hook method. This method fails if this viewer does not have a content provider. Subclassers are advised to override inputChanged rather than this method, but may extend this method if required.

Specified by:

setInput in class Viewer

Parameters:

input - the input of this viewer, or null if none

setLabelProvider

public void setLabelProvider(IBaseLabelProvider labelProvider)

Sets the label provider for this viewer.

The ContentViewer implementation of this method ensures that the given label provider is connected to this viewer and the former label provider is disconnected from this viewer. Overriding this method is generally not required; however, if overriding in a subclass, super.setLabelProvider must be invoked.

Parameters:

labelProvider - the label provider, or null if none