GWT CellBrowser组件
GWT CellBrowser组件 介绍
CellBrowser组件代表可浏览的，其中只有每级的单个节点可以是开放的一次树的图。
GWT CellBrowser组件 声明
以下是com.google.gwt.user.client.ui.CellBrowser类的声明
public class CellBrowser
extends AbstractCellTree
implements ProvidesResize, RequiresResize, HasAnimation
GWT CellBrowser组件 构造方法
| 构造方法 | 描述 |
|---|---|
| CellBrowser(TreeViewModel viewModel, T rootValue) | 构建一个新的 CellBrowser。 |
| CellBrowser(TreeViewModel viewModel, T rootValue, CellBrowser.Resources resources) | 使用指定的 CellBrowser.Resources 构造一个新的 CellBrowser。 |
GWT CellBrowser组件 方法
| 方法 | 描述 |
|---|---|
| protected <C> Widget createPager(HasData<C> display) | 创建一个Pager来控制列表视图。 |
| int getDefaultColumnWidth() | 获取新列的默认宽度。 |
| int getMinimumColumnWidth() | 获取列的最小宽度。 |
| TreeNode getRootTreeNode() | 获取根 TreeNode。 |
| boolean isAnimationEnabled() | 如果启用动画，则返回 true，否则返回 false。 |
| void onBrowserEvent(Event event) | 每当接收到浏览器事件时触发。 |
| void onResize() | 只要修改了实现者的大小，就必须调用此方法。 |
| void setAnimationEnabled(boolean enable) | 启用或禁用动画。 |
| void setDefaultColumnWidth(int width) | 设置新列的默认宽度。 |
| void set Keyboard Selection Policy (Has Keyboard Selection Policy.Keyboard Selection Policy policy) | 设置 HasKeyboardSelectionPolicy.KeyboardSelectionPolicy。 |
| void setMinimumColumnWidth(int minWidth) | 设置列的最小宽度。 |
GWT Tree组件 示例
1）修改HelloWorld.gwt.xml
<!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 2.8.0//EN"
"http://gwtproject.org/doctype/2.8.0/gwt-module.dtd">
<module rename-to="HelloWorld">
<!-- Inherit the core Web Toolkit stuff. -->
<inherits name='com.google.gwt.user.User'/>
<!-- Specify the app entry point class. -->
<entry-point class='com.yiidian.helloWorld.client.HelloWorld'/>
<!-- Specify the app servlets. -->
<servlet path='/HelloWorldService' class='com.yiidian.helloWorld.server.HelloWorldServiceImpl'/>
<source path = 'client'/>
<source path = 'shared'/>
</module>
2）修改HelloWorld.css
body {
text-align: center;
font-family: verdana, sans-serif;
}
h1 {
font-size: 2em;
font-weight: bold;
color: #777777;
margin: 40px 0px 70px;
text-align: center;
}
3）修改HelloWorld.html
<html>
<head>
<title>yiidian.com-GWT Hello World</title>
<link type="text/css" rel="stylesheet" href="HelloWorld.css">
<script type="text/javascript" language="javascript" src="HelloWorld/HelloWorld.nocache.js"></script>
</head>
<body>
<h1>CellBrowser Widget Demonstration</h1>
<div id = "gwtContainer"></div>
</body>
</html>
4）HelloWorld.java
package com.yiidian.helloWorld.client;
import com.google.gwt.cell.client.AbstractCell;
import com.google.gwt.cell.client.Cell;
import com.google.gwt.cell.client.DateCell;
import com.google.gwt.cell.client.TextCell;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.google.gwt.user.cellview.client.*;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.*;
import com.google.gwt.view.client.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
/**
* Entry point classes define <code>onModuleLoad()</code>
*/
public class HelloWorld 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<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) {
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(HasKeyboardSelectionPolicy.KeyboardSelectionPolicy.ENABLED);
browser.setHeight("200");
browser.setWidth("630");
VerticalPanel panel = new VerticalPanel();
panel.setBorderWidth(1);
panel.add(browser);
// Add the widgets to the root panel.
RootPanel.get().add(panel);
}
}
运行应用程序，显示结果如下：
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