GWT - HorizontalPanel Widget


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Introduction

The HorizantalPanel widget represents a panel that lays all of its widgets out in a single horizontal column.

Class Declaration

Following is the declaration for com.google.gwt.user.client.ui.HorizontalPanel class −

public class HorizontalPanel
   extends CellPanel
      implements HasAlignment, InsertPanel.ForIsWidget

Class Constructors

Sr.No. Constructor & Description
1

HorizontalPanel()

Constructor for empty horizontal Panel

Class Methods

Sr.No. Function name & Description
1

void add(Widget w)

Adds a child widget.

2

HasHorizontalAlignment.HorizontalAlignmentConstant getHorizontalAlignment()

Gets the horizontal alignment.

3

HasVerticalAlignment.VerticalAlignmentConstant getVerticalAlignment()

Gets the vertical alignment.

4

void insert(IsWidget w, int beforeIndex)

5

void insert(Widget w, int beforeIndex)

Inserts a child widget before the specified index.

6

protected void onEnsureDebugId(java.lang.String baseID)

Affected Elements: -# = the cell at the given index.

7

boolean remove(Widget w)

Removes a child widget.

8

void set Horizontal Alignment(HasHorizontalAlignment. HorizontalAlignmentConstantalign)

Sets the default horizontal alignment to be used for widgets added to this panel.

9

void setVerticalAlignment(HasVerticalAlignment. VerticalAlignmentConstantalign)

Sets the default vertical alignment to be used for widgets added to this panel.

Methods Inherited

This class inherits methods from the following classes −

  • 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

HorizontalPanel Widget Example

This example will take you through simple steps to show usage of a HorizontalPanel Widget in GWT. Follow the following steps to update the GWT application we created in GWT - Create Application chapter −

Step Description
1 Create a project with a name HelloWorld under a package com.tutorialspoint as explained in the GWT - Create Application chapter.
2 Modify HelloWorld.gwt.xml, HelloWorld.css, HelloWorld.html and HelloWorld.java as explained below. Keep rest of the files unchanged.
3 Compile and run the application to verify the result of the implemented logic.

Following is the content of the modified module descriptor src/com.tutorialspoint/HelloWorld.gwt.xml.

<?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>

Following is the content of the modified Style Sheet file war/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;
}

.gwt-CheckBox {
   margin: 10px;	
}

Following is the content of the modified HTML host file war/HelloWorld.html.

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

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

Let us have following content of Java file src/com.tutorialspoint/HelloWorld.java which will demonstrate use of HorizontalPanel widget.

package com.tutorialspoint.client;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.CheckBox;
import com.google.gwt.user.client.ui.DecoratorPanel;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.RootPanel;

public class HelloWorld implements EntryPoint {

   public void onModuleLoad() {
      // Create a horizontal panel			
      HorizontalPanel horizontalPanel = new HorizontalPanel();

      // Add CheckBoxes to horizontal Panel
      for(int i = 1;  i <= 10; i++){
         CheckBox checkBox = new CheckBox("Item" + i);
         horizontalPanel.add(checkBox);
      }

      DecoratorPanel decoratorPanel = new DecoratorPanel();
      decoratorPanel.setWidth("500");
      decoratorPanel.add(horizontalPanel);

      // Add the widgets to the root panel.
      RootPanel.get().add(decoratorPanel);
   }
}

Once you are ready with all the changes done, let us compile and run the application in development mode as we did in GWT - Create Application chapter. If everything is fine with your application, this will produce following result −

GWT HorizontalPanel Widget
gwt_layout_panels.htm
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