com.google.gwt.user.cellview.client

## Class CellBrowser

- java.lang.Object
- - com.google.gwt.user.client.ui.UIObject
  - - com.google.gwt.user.client.ui.Widget
    - - com.google.gwt.user.client.ui.Composite
      - - com.google.gwt.user.cellview.client.AbstractCellTree
        - - com.google.gwt.user.cellview.client.CellBrowser

All Implemented Interfaces:
  HasAttachHandlers, HasCloseHandlers<TreeNode>, HasOpenHandlers<TreeNode>, HasHandlers, HasKeyboardSelectionPolicy, EventListener, HasAnimation, HasVisibility, IsRenderable, IsWidget, ProvidesResize, RequiresResize

    public class CellBrowser
    extends AbstractCellTree
    implements ProvidesResize, RequiresResize, HasAnimation

A "browsable" view of a tree in which only a single node per level may be open at one time.

This widget will only work in standards mode, which requires that the HTML page in which it is run have an explicit <!DOCTYPE> declaration.

### Example

Trivial example

  >     public class CellBrowserExample implements EntryPoint {

  >       /**
  >        * The model that defines the nodes in the tree.
  >        */
  >       private static class CustomTreeModel implements TreeViewModel {

  >         /**
  >          * Get the {@link NodeInfo} that provides the children of the specified
  >          * value.
  >          */
  >         public <T> NodeInfo<?> getNodeInfo(T value) {
  >           /*
  >            * Create some data in a data provider. Use the parent value as a prefix
  >            * for the next level.
  >            */
  >           ListDataProvider<String> dataProvider = new ListDataProvider<String>();
  >           for (int i = 0; i < 2; i++) {
  >             dataProvider.getList().add(value + "." + String.valueOf(i));
  >           }

  >           // Return a node info that pairs the data with a cell.
  >           return new DefaultNodeInfo<String>(dataProvider, new TextCell());
  >         }

  >         /**
  >          * Check if the specified value represents a leaf node. Leaf nodes cannot be
  >          * opened.
  >          */
  >         public boolean isLeaf(Object value) {
  >           // The maximum length of a value is ten characters.
  >           return value.toString().length() > 10;
  >         }
  >       }

  >       public void onModuleLoad() {
  >         // Create a model for the browser.
  >         TreeViewModel model = new CustomTreeModel();

  >         /*
  >          * Create the browser using the model. We specify the default value of the
  >          * hidden root node as "Item 1".
  >          */
  >         CellBrowser tree = new CellBrowser(model, "Item 1");

  >         // Add the tree to the root layout panel.
  >         RootLayoutPanel.get().add(tree);
  >       }
  >     }

Complex example

  >     public class CellBrowserExample2 implements EntryPoint {

  >       /**
  >        * A list of songs.
  >        */
  >       private static class Playlist {
  >         private final String name;
  >         private final List<String> songs = new ArrayList<String>();

  >         public Playlist(String name) {
  >           this.name = name;
  >         }

  >         /**
  >          * Add a song to the playlist.
  >          *
  >          * @param name the name of the song
  >          */
  >         public void addSong(String name) {
  >           songs.add(name);
  >         }

  >         public String getName() {
  >           return name;
  >         }

  >         /**
  >          * Return the list of songs in the playlist.
  >          */
  >         public List<String> getSongs() {
  >           return songs;
  >         }
  >       }

  >       /**
  >        * A composer of classical music.
  >        */
  >       private static class Composer {
  >         private final String name;
  >         private final List<Playlist> playlists = new ArrayList<Playlist>();

  >         public Composer(String name) {
  >           this.name = name;
  >         }

  >         /**
  >          * Add a playlist to the composer.
  >          *
  >          * @param playlist the playlist to add
  >          */
  >         public Playlist addPlaylist(Playlist playlist) {
  >           playlists.add(playlist);
  >           return playlist;
  >         }

  >         public String getName() {
  >           return name;
  >         }

  >         /**
  >          * Return the rockin' playlist for this composer.
  >          */
  >         public List<Playlist> getPlaylists() {
  >           return playlists;
  >         }
  >       }

  >       /**
  >        * The model that defines the nodes in the tree.
  >        */
  >       private static class CustomTreeModel implements TreeViewModel {

  >         private final List<Composer> composers;

  >         /**
  >          * This selection model is shared across all leaf nodes. A selection model
  >          * can also be shared across all nodes in the tree, or each set of child
  >          * nodes can have its own instance. This gives you flexibility to determine
  >          * how nodes are selected.
  >          */
  >         private final SingleSelectionModel<String> selectionModel = new SingleSelectionModel<String>();

  >         public CustomTreeModel() {
  >           // Create a database of information.
  >           composers = new ArrayList<Composer>();

  >           // Add compositions by Beethoven.
  >           {
  >             Composer beethoven = new Composer("Beethoven");
  >             composers.add(beethoven);

  >             Playlist concertos = beethoven.addPlaylist(new Playlist("Concertos"));
  >             concertos.addSong("No. 1 - C");
  >             concertos.addSong("No. 2 - B-Flat Major");
  >             concertos.addSong("No. 3 - C Minor");
  >             concertos.addSong("No. 4 - G Major");
  >             concertos.addSong("No. 5 - E-Flat Major");

  >             Playlist quartets = beethoven.addPlaylist(new Playlist("Quartets"));
  >             quartets.addSong("Six String Quartets");
  >             quartets.addSong("Three String Quartets");
  >             quartets.addSong("Grosse Fugue for String Quartets");

  >             Playlist sonatas = beethoven.addPlaylist(new Playlist("Sonatas"));
  >             sonatas.addSong("Sonata in A Minor");
  >             sonatas.addSong("Sonata in F Major");

  >             Playlist symphonies = beethoven.addPlaylist(new Playlist("Symphonies"));
  >             symphonies.addSong("No. 2 - D Major");
  >             symphonies.addSong("No. 2 - D Major");
  >             symphonies.addSong("No. 3 - E-Flat Major");
  >             symphonies.addSong("No. 4 - B-Flat Major");
  >             symphonies.addSong("No. 5 - C Minor");
  >             symphonies.addSong("No. 6 - F Major");
  >             symphonies.addSong("No. 7 - A Major");
  >             symphonies.addSong("No. 8 - F Major");
  >             symphonies.addSong("No. 9 - D Minor");
  >           }

  >           // Add compositions by Brahms.
  >           {
  >             Composer brahms = new Composer("Brahms");
  >             composers.add(brahms);
  >             Playlist concertos = brahms.addPlaylist(new Playlist("Concertos"));
  >             concertos.addSong("Violin Concerto");
  >             concertos.addSong("Double Concerto - A Minor");
  >             concertos.addSong("Piano Concerto No. 1 - D Minor");
  >             concertos.addSong("Piano Concerto No. 2 - B-Flat Major");

  >             Playlist quartets = brahms.addPlaylist(new Playlist("Quartets"));
  >             quartets.addSong("Piano Quartet No. 1 - G Minor");
  >             quartets.addSong("Piano Quartet No. 2 - A Major");
  >             quartets.addSong("Piano Quartet No. 3 - C Minor");
  >             quartets.addSong("String Quartet No. 3 - B-Flat Minor");

  >             Playlist sonatas = brahms.addPlaylist(new Playlist("Sonatas"));
  >             sonatas.addSong("Two Sonatas for Clarinet - F Minor");
  >             sonatas.addSong("Two Sonatas for Clarinet - E-Flat Major");

  >             Playlist symphonies = brahms.addPlaylist(new Playlist("Symphonies"));
  >             symphonies.addSong("No. 1 - C Minor");
  >             symphonies.addSong("No. 2 - D Minor");
  >             symphonies.addSong("No. 3 - F Major");
  >             symphonies.addSong("No. 4 - E Minor");
  >           }

  >           // Add compositions by Mozart.
  >           {
  >             Composer mozart = new Composer("Mozart");
  >             composers.add(mozart);
  >             Playlist concertos = mozart.addPlaylist(new Playlist("Concertos"));
  >             concertos.addSong("Piano Concerto No. 12");
  >             concertos.addSong("Piano Concerto No. 17");
  >             concertos.addSong("Clarinet Concerto");
  >             concertos.addSong("Violin Concerto No. 5");
  >             concertos.addSong("Violin Concerto No. 4");
  >           }
  >         }

  >         /**
  >          * Get the {@link NodeInfo} that provides the children of the specified
  >          * value.
  >          */
  >         public <T> NodeInfo<?> getNodeInfo(T value) {
  >           if (value == null) {
  >             // LEVEL 0.
  >             // We passed null as the root value. Return the composers.

  >             // Create a data provider that contains the list of composers.
  >             ListDataProvider<Composer> dataProvider = new ListDataProvider<CellBrowserExample2.Composer>(
  >                 composers);

  >             // Create a cell to display a composer.
  >             Cell<Composer> cell = new AbstractCell<Composer>() {
  >               @Override
  >               public void render(Context context, Composer value, SafeHtmlBuilder sb) {
  >                 if (value != null) {
  >                   sb.appendEscaped(value.getName());
  >                 }
  >               }
  >             };

  >             // Return a node info that pairs the data provider and the cell.
  >             return new DefaultNodeInfo<Composer>(dataProvider, cell);
  >           } else if (value instanceof Composer) {
  >             // LEVEL 1.
  >             // We want the children of the composer. Return the playlists.
  >             ListDataProvider<Playlist> dataProvider = new ListDataProvider<Playlist>(
  >                 ((Composer) value).getPlaylists());
  >             Cell<Playlist> cell = new AbstractCell<Playlist>() {
  >               @Override
  >               public void render(Context context, Playlist value, SafeHtmlBuilder sb) {
  >                 if (value != null) {
  >                   sb.appendEscaped(value.getName());
  >                 }
  >               }
  >             };
  >             return new DefaultNodeInfo<Playlist>(dataProvider, cell);
  >           } else if (value instanceof Playlist) {
  >             // LEVEL 2 - LEAF.
  >             // We want the children of the playlist. Return the songs.
  >             ListDataProvider<String> dataProvider = new ListDataProvider<String>(
  >                 ((Playlist) value).getSongs());

  >             // Use the shared selection model.
  >             return new DefaultNodeInfo<String>(dataProvider, new TextCell(),
  >                 selectionModel, null);
  >           }

  >           return null;
  >         }

  >         /**
  >          * Check if the specified value represents a leaf node. Leaf nodes cannot be
  >          * opened.
  >          */
  >         public boolean isLeaf(Object value) {
  >           // The leaf nodes are the songs, which are Strings.
  >           if (value instanceof String) {
  >             return true;
  >           }
  >           return false;
  >         }

  >       }

  >       public void onModuleLoad() {
  >         // Create a model for the browser.
  >         TreeViewModel model = new CustomTreeModel();

  >         /*
  >          * Create the browser using the model. We use <code>null</code> as the
  >          * default value of the root node. The default value will be passed to
  >          * CustomTreeModel#getNodeInfo();
  >          */
  >         CellBrowser browser = new CellBrowser(model, null);
  >         browser.setKeyboardSelectionPolicy(KeyboardSelectionPolicy.ENABLED);

  >         // Add the browser to the root layout panel.
  >         RootLayoutPanel.get().add(browser);
  >       }
  >     }

### Nested Class Summary

Nested Classes
`(package private) class` `CellBrowser.BrowserCellList<T>` A custom version of cell list used by the browser.
`static class` `CellBrowser.Builder<T>` Builder object to create CellBrowser.
`static interface` `CellBrowser.PagerFactory` Pager factory used to create pagers for each `CellList` of the `CellBrowser`.
`static interface` `CellBrowser.Resources` A ClientBundle that provides images for this widget.
`static interface` `CellBrowser.Style` Styles used by this widget.
`(package private) static interface` `CellBrowser.Template`
`(package private) class` `CellBrowser.TreeNodeImpl<C>` A node in the tree.

### Nested classes/interfaces inherited from class com.google.gwt.user.client.ui.UIObject

`UIObject.DebugIdImpl, UIObject.DebugIdImplEnabled`

### Nested classes/interfaces inherited from interface com.google.gwt.user.cellview.client.HasKeyboardSelectionPolicy

`HasKeyboardSelectionPolicy.KeyboardSelectionPolicy`

### Field Summary

Fields
`(package private) java.util.List<CellBrowser.TreeNodeImpl<?>>` `treeNodes` The visible `CellBrowser.TreeNodeImpl`s.

### Fields inherited from class com.google.gwt.user.client.ui.UIObject

`DEBUG_ID_PREFIX`

### Constructor Summary

Constructors
`protected` `CellBrowser(CellBrowser.Builder<T> builder)`
`` `CellBrowser(TreeViewModel viewModel, T rootValue)` Deprecated. please use `CellBrowser.Builder`
`` `CellBrowser(TreeViewModel viewModel, T rootValue, CellBrowser.Resources resources)` Deprecated. please use `CellBrowser.Builder`

### Method Summary

All Methods Instance Methods Concrete Methods
`protected <C> Widget` `createPager(HasData<C> display)` Create a pager to control the list view.
`int` `getDefaultColumnWidth()` Get the default width of new columns.
`int` `getMinimumColumnWidth()` Get the minimum width of columns.
`TreeNode` `getRootTreeNode()` Get the root `TreeNode`.
`boolean` `isAnimationEnabled()` Returns true if animations are enabled, false if not.
`void` `onBrowserEvent(Event event)` Fired whenever a browser event is received.
`void` `onResize()` This method must be called whenever the implementor's size has been modified.
`void` `setAnimationEnabled(boolean enable)` Enable or disable animations.
`void` `setDefaultColumnWidth(int width)` Set the default width of new columns.
`void` `setMinimumColumnWidth(int minWidth)` Set the minimum width of columns.

### Methods inherited from class com.google.gwt.user.cellview.client.AbstractCellTree

`addCloseHandler, addOpenHandler, getKeyboardSelectionPolicy, getNodeInfo, getTreeViewModel, isKeyboardSelectionDisabled, isLeaf, setKeyboardSelectionPolicy`

### Methods inherited from class com.google.gwt.user.client.ui.Composite

`claimElement, getWidget, initializeClaimedElement, initWidget, isAttached, onAttach, onDetach, render, render, resolvePotentialElement, setWidget`

### Methods inherited from class com.google.gwt.user.client.ui.Widget

`addAttachHandler, addBitlessDomHandler, addDomHandler, addHandler, asWidget, asWidgetOrNull, createHandlerManager, delegateEvent, doAttachChildren, doDetachChildren, fireEvent, getHandlerCount, getLayoutData, getParent, isOrWasAttached, onLoad, onUnload, removeFromParent, setLayoutData, sinkEvents, unsinkEvents`

### Methods inherited from class com.google.gwt.user.client.ui.UIObject

`addStyleDependentName, addStyleName, ensureDebugId, ensureDebugId, ensureDebugId, getAbsoluteLeft, getAbsoluteTop, getElement, getOffsetHeight, getOffsetWidth, getStyleElement, getStyleName, getStyleName, getStylePrimaryName, getStylePrimaryName, getTitle, isVisible, isVisible, onEnsureDebugId, removeStyleDependentName, removeStyleName, setElement, setElement, setHeight, setPixelSize, setSize, setStyleDependentName, setStyleName, setStyleName, setStyleName, setStyleName, setStylePrimaryName, setStylePrimaryName, setTitle, setVisible, setVisible, setWidth, sinkBitlessEvent, toString`

### Methods inherited from class java.lang.Object

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

### Methods inherited from interface com.google.gwt.event.shared.HasHandlers

`fireEvent`

### Field Detail

#### treeNodes

    final java.util.List<CellBrowser.TreeNodeImpl<?>> treeNodes

The visible `CellBrowser.TreeNodeImpl`s. Visible for testing.

### Constructor Detail

#### CellBrowser

    @Deprecated
    public CellBrowser(TreeViewModel viewModel,
                                   T rootValue)

Deprecated. please use `CellBrowser.Builder`
Construct a new `CellBrowser`.

Type Parameters:
  `T` - the type of data in the root node
Parameters:
  `viewModel` - the `TreeViewModel` that backs the tree
  `rootValue` - the hidden root value of the tree

#### CellBrowser

    @Deprecated
    public CellBrowser(TreeViewModel viewModel,
                                   T rootValue,
                                   CellBrowser.Resources resources)

Deprecated. please use `CellBrowser.Builder`
Construct a new `CellBrowser` with the specified `CellBrowser.Resources`.

Type Parameters:
  `T` - the type of data in the root node
Parameters:
  `viewModel` - the `TreeViewModel` that backs the tree
  `rootValue` - the hidden root value of the tree
  `resources` - the `CellBrowser.Resources` used for images

#### CellBrowser

    protected CellBrowser(CellBrowser.Builder<T> builder)

### Method Detail

#### getDefaultColumnWidth

    public int getDefaultColumnWidth()

Get the default width of new columns.

Returns:
  the default width in pixels
See Also:
  `setDefaultColumnWidth(int)`

#### getMinimumColumnWidth

    public int getMinimumColumnWidth()

Get the minimum width of columns.

Returns:
  the minimum width in pixels
See Also:
  `setMinimumColumnWidth(int)`

#### getRootTreeNode

    public TreeNode getRootTreeNode()

Description copied from class: `AbstractCellTree`
Get the root `TreeNode`.

Specified by:
  `getRootTreeNode` in class `AbstractCellTree`
Returns:
  the `TreeNode` at the root of the tree

#### isAnimationEnabled

    public boolean isAnimationEnabled()

Description copied from interface: `HasAnimation`
Returns true if animations are enabled, false if not.

Specified by:
  `isAnimationEnabled` in interface `HasAnimation`

#### onBrowserEvent

    public void onBrowserEvent(Event event)

Description copied from interface: `EventListener`
Fired whenever a browser event is received.

Specified by:
  `onBrowserEvent` in interface `EventListener`
Overrides:
  `onBrowserEvent` in class `Composite`
Parameters:
  `event` - the event received

#### onResize

    public void onResize()

Description copied from interface: `RequiresResize`
This method must be called whenever the implementor's size has been modified.

Specified by:
  `onResize` in interface `RequiresResize`

#### setAnimationEnabled

    public void setAnimationEnabled(boolean enable)

Description copied from interface: `HasAnimation`
Enable or disable animations.

Specified by:
  `setAnimationEnabled` in interface `HasAnimation`
Parameters:
  `enable` - true to enable, false to disable

#### setDefaultColumnWidth

    public void setDefaultColumnWidth(int width)

Set the default width of new columns.

Parameters:
  `width` - the default width in pixels
See Also:
  `getDefaultColumnWidth()`

#### setMinimumColumnWidth

    public void setMinimumColumnWidth(int minWidth)

Set the minimum width of columns.

Parameters:
  `minWidth` - the minimum width in pixels
See Also:
  `getMinimumColumnWidth()`

#### createPager

    protected <C> Widget createPager(HasData<C> display)

Create a pager to control the list view.

Type Parameters:
  `C` - the item type in the list view
Parameters:
  `display` - the list view to add paging too
Returns:
  the pager