com.google.gwt.cell.client

Class AbstractCell<C>

java.lang.Object

com.google.gwt.cell.client.AbstractCell<C>

Type Parameters:

C - the type that this Cell represents

All Implemented Interfaces:

Cell<C>

Direct Known Subclasses:

AbstractEditableCell, AbstractSafeHtmlCell, ActionCell, ButtonCellBase, CompositeCell, DateCell, ImageCell, ImageLoadingCell, ImageResourceCell, NumberCell, SafeHtmlCell, SafeImageCell

public abstract class AbstractCell<C>
extends Object
implements Cell<C>

A default implementation of the Cell interface.

Examples

Read only cell

Cell with events

Interactive cell

Editable cell

Nested Class Summary

Nested classes/interfaces inherited from interface com.google.gwt.cell.client.Cell

Cell.Context

Constructor Summary

Constructors

Constructor and Description
AbstractCell(Set<String> consumedEvents) Construct a new AbstractCell with the specified consumed events.
AbstractCell(String... consumedEvents) Construct a new AbstractCell with the specified consumed events.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	dependsOnSelection() Check if this cell depends on the selection state.
Set<String>	getConsumedEvents() Get the set of events that this cell consumes (see BrowserEvents for useful constants).
boolean	handlesSelection() Check if this cell handles selection.
boolean	isEditing(Cell.Context context, Element parent, C value) Returns false.
void	onBrowserEvent(Cell.Context context, Element parent, C value, NativeEvent event, ValueUpdater<C> valueUpdater) Handle a browser event that took place within the cell.
protected void	onEnterKeyDown(Cell.Context context, Element parent, C value, NativeEvent event, ValueUpdater<C> valueUpdater) Called when the user triggers a keydown event with the ENTER key while focused on the cell.
abstract void	render(Cell.Context context, C value, SafeHtmlBuilder sb) Render a cell as HTML into a SafeHtmlBuilder, suitable for passing to Element.setInnerHTML(String) on a container element.
boolean	resetFocus(Cell.Context context, Element parent, C value) Reset focus on the Cell.
void	setValue(Cell.Context context, Element parent, C value) This method may be used by cell containers to set the value on a single cell directly, rather than using Element.setInnerHTML(String).

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, toString

Constructor Detail

AbstractCell

public AbstractCell(String... consumedEvents)

Construct a new AbstractCell with the specified consumed events. The input arguments are passed by copy.

Parameters:

consumedEvents - the events that this cell consumes

See Also:

BrowserEvents

AbstractCell

public AbstractCell(Set<String> consumedEvents)

Construct a new AbstractCell with the specified consumed events.

Parameters:

consumedEvents - the events that this cell consumes

Method Detail

dependsOnSelection

public boolean dependsOnSelection()

Description copied from interface: Cell

Check if this cell depends on the selection state.

Specified by:

dependsOnSelection in interface Cell<C>

Returns:

true if dependent on selection, false if not

getConsumedEvents

public Set<String> getConsumedEvents()

Description copied from interface: Cell

Get the set of events that this cell consumes (see BrowserEvents for useful constants). The container that uses this cell should only pass these events to Cell.onBrowserEvent(Context, Element, Object, NativeEvent, ValueUpdater) when the event occurs.

The returned value should not be modified, and may be an unmodifiable set. Changes to the return value may not be reflected in the cell.

Specified by:

getConsumedEvents in interface Cell<C>

Returns:

the consumed events, or null if no events are consumed

See Also:

BrowserEvents

handlesSelection

public boolean handlesSelection()

Description copied from interface: Cell

Check if this cell handles selection. If the cell handles selection, then its container should not automatically handle selection.

Specified by:

handlesSelection in interface Cell<C>

Returns:

true if the cell handles selection, false if not

isEditing

public boolean isEditing(Cell.Context context,
                Element parent,
                C value)

Returns false. Subclasses that support editing should override this method to return the current editing status.

Specified by:

isEditing in interface Cell<C>

Parameters:

context - the Cell.Context of the cell

parent - the parent Element

value - the value associated with the cell

Returns:

true if the cell is in edit mode

onBrowserEvent

public void onBrowserEvent(Cell.Context context,
                  Element parent,
                  C value,
                  NativeEvent event,
                  ValueUpdater<C> valueUpdater)

Handle a browser event that took place within the cell. The default implementation returns null.

If you override this method to add support for events, remember to pass the event types that the cell expects into the constructor.

Specified by:

onBrowserEvent in interface Cell<C>

Parameters:

context - the Cell.Context of the cell

parent - the parent Element

value - the value associated with the cell

event - the native browser event

valueUpdater - a ValueUpdater, or null if not specified

render

public abstract void render(Cell.Context context,
          C value,
          SafeHtmlBuilder sb)

Description copied from interface: Cell

Render a cell as HTML into a SafeHtmlBuilder, suitable for passing to Element.setInnerHTML(String) on a container element.

Note: If your cell contains natively focusable elements, such as buttons or input elements, be sure to set the tabIndex to -1 so that they do not steal focus away from the containing widget.

Specified by:

render in interface Cell<C>

Parameters:

context - the Cell.Context of the cell

value - the cell value to be rendered

sb - the SafeHtmlBuilder to be written to

resetFocus

public boolean resetFocus(Cell.Context context,
                 Element parent,
                 C value)

Reset focus on the Cell. This method is called if the cell has focus when it is refreshed.

This method is a no-op and returns false. If your cell is editable or can be focused by the user, override this method to reset focus when the containing widget is refreshed.

Specified by:

resetFocus in interface Cell<C>

Parameters:

context - the Cell.Context of the cell

parent - the parent Element

value - the value associated with the cell

Returns:

true if focus is taken, false if not

setValue

public void setValue(Cell.Context context,
            Element parent,
            C value)

Description copied from interface: Cell

This method may be used by cell containers to set the value on a single cell directly, rather than using Element.setInnerHTML(String). See Cell.setValue(Context, Element, Object) for a default implementation that uses Cell.render(Context, Object, SafeHtmlBuilder).

Specified by:

setValue in interface Cell<C>

Parameters:

context - the Cell.Context of the cell

parent - the parent Element

value - the value associated with the cell

onEnterKeyDown

protected void onEnterKeyDown(Cell.Context context,
                  Element parent,
                  C value,
                  NativeEvent event,
                  ValueUpdater<C> valueUpdater)

Called when the user triggers a keydown event with the ENTER key while focused on the cell. If your cell interacts with the user, you should override this method to provide a consistent user experience. Your widget must consume keydown events for this method to be called.

Parameters:

context - the Context of the cell

parent - the parent Element

value - the value associated with the cell

event - the native browser event

valueUpdater - a ValueUpdater, or null if not specified