GWT - DockPanel 小部件

简介

DockPanel 小部件表示一个面板，该面板将其子小部件"停靠"在其外边缘，并允许其最后一个小部件占据其中心的剩余空间。

类声明

以下是 com.google.gwt.user.client.ui.DockPanel 类的声明 −

@Deprecated
public class DockPanel
   extends CellPanel
      implements HasAlignment

类构造函数

类方法

继承的方法

该类继承了以下类的方法 −

• com.google.gwt.user.client.ui.UIObject

• com.google.gwt.user.client.ui.Widget

• com.google.gwt.user.client.ui.Panel

• com.google.gwt.user.client.ui.ComplexPanel

• com.google.gwt.user.client.ui.CellPanel

• java.lang.Object

DockPanel Widget 示例

此示例将带您通过简单的步骤展示 GWT 中 DockPanel Widget 的使用方法。按照以下步骤更新我们在 GWT - 创建应用程序 一章中创建的 GWT 应用程序 −

以下是修改后的模块描述符src/com.tutorialspoint/HelloWorld.gwt.xml的内容。

<?xml version = "1.0" encoding = "UTF-8"?>
<module rename-to = 'helloworld'>
   <!-- Inherit the core Web Toolkit stuff.                        -->
   <inherits name = 'com.google.gwt.user.User'/>

   <!-- Inherit the default GWT style sheet.                       -->
   <inherits name = 'com.google.gwt.user.theme.clean.Clean'/>

   <!-- Specify the app entry point class.                         -->
   <entry-point class = 'com.tutorialspoint.client.HelloWorld'/>

   <!-- Specify the paths for translatable code                    -->
   <source path = 'client'/>
   <source path = 'shared'/>

</module>

以下是修改后的样式表文件war/HelloWorld.css的内容。

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;
}
.dockpanel td {
   border: 1px solid #BBBBBB;
   padding: 3px;
}

以下是修改后的 HTML 主机文件 war/HelloWorld.html 的内容。

<html>
   <head>
      <title>Hello World</title>
      <link rel = "stylesheet" href = "HelloWorld.css"/>
      <script language = "javascript" src = "helloworld/helloworld.nocache.js">
      </script>
   </head>

   <body>
      <h1>DockPanel Widget Demonstration</h1>
      <div id = "gwtContainer"></div>
   </body>
</html>

让我们来看看 Java 文件 src/com.tutorialspoint/HelloWorld.java 的以下内容，它将演示如何使用 DockPanel 小部件。

package com.tutorialspoint.client;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.DockPanel;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.ScrollPanel;
import com.google.gwt.user.client.ui.VerticalPanel;

public class HelloWorld implements EntryPoint {

   public void onModuleLoad() {
      DockPanel dockPanel = new DockPanel();
      dockPanel.setStyleName("dockpanel");
      dockPanel.setSpacing(4);
      dockPanel.setHorizontalAlignment(DockPanel.ALIGN_CENTER);

      // 添加四周的文字
      dockPanel.add(new HTML("This is the first north component."), 
      DockPanel.NORTH);
      dockPanel.add(new HTML("This is the first south component."), 
      DockPanel.SOUTH);
      dockPanel.add(new HTML("This is the east component."), 
      DockPanel.EAST);
      dockPanel.add(new HTML("This is the west component."), 
      DockPanel.WEST);
      dockPanel.add(new HTML("This is the second north component."), 
      DockPanel.NORTH);
      dockPanel.add(new HTML("This is the second south component"), 
      DockPanel.SOUTH);

      // 在中心添加可滚动的文本
      HTML contents = new HTML("This is a ScrollPanel contained"
         +" at the center of a DockPanel. "
         +" By putting some fairly large contents in the middle"
         +" and setting its size explicitly, it becomes a scrollable area"
         +" within the page, but without requiring the use of an IFRAME."
         +" Here's quite a bit more meaningless text that will serve primarily"
         +" to make this thing scroll off the bottom of its visible area."
         +" Otherwise, you might have to make it really, really"
         +" small in order to see the nifty scroll bars!");
      ScrollPanel scroller = new ScrollPanel(contents);
      scroller.setSize("400px", "100px");
      dockPanel.add(scroller, DockPanel.CENTER);

      VerticalPanel vPanel = new VerticalPanel();
      vPanel.add(dockPanel);

      // 将小部件添加到根面板。
      RootPanel.get().add(vPanel);
   }
}

完成所有更改后，让我们像在 GWT - 创建应用程序 一章中一样，在开发模式下编译并运行应用程序。如果您的应用程序一切正常，这将产生以下结果 −

gwt_layout_panels.html