GWT - RadioButton Widget

Introduction

The RadioButton widget represents a mutually exclusive selection radio button.

Class declaration

Following is the declaration for com.google.gwt.user.client.ui.RadioButton class:

public class RadioButton
   extends CheckBox

CSS style rules

Following default CSS Style rules will be applied to all the RadioButton widget. You can override it as per your requirements.

.gwt-RadioButton {}

Class constructors

S.N.	Constructor & Description
1	RadioButton(java.lang.String name) Creates a new radio associated with a particular group name.
2	RadioButton(java.lang.String name,java.lang.String label) Creates a new radio associated with a particular group, and initialized with the given HTML label.
3	RadioButton(java.lang.String name,java.lang.String label, boolean asHTML) Creates a new radio button associated with a particular group, and initialized with the given label (optionally treated as HTML).

Class methods

S.N.	Function name & Description
1	void setName(java.lang.String name) Change the group name of this radio button.

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.FocusWidget
com.google.gwt.user.client.ui.CheckBox
java.lang.Object

RadioButton Widget Example

This example will take you through simple steps to show usage of a RadioButton 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-RadioButton{ 
   color:green;   
}

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>RadioButton 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 RadioButton widget.

package com.tutorialspoint.client;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.RadioButton;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.VerticalPanel;

public class HelloWorld implements EntryPoint {
   public void onModuleLoad() {

       // Create some radio buttons, all in one group 'radioGroup'.
       RadioButton radioButton1 = new RadioButton("radioGroup", "First");
       RadioButton radioButton2 = new RadioButton("radioGroup", "Second");
       RadioButton radioButton3 = new RadioButton("radioGroup", "Third");

       // Check 'First' by default.
       radioButton1.setValue(true);

      //disable 'Second' radio button
      radioButton2.setEnabled(false);

      // Add toggle button to the root panel.
      VerticalPanel panel = new VerticalPanel();
      panel.setSpacing(10);            
      panel.add(radioButton1);
      panel.add(radioButton2);
      panel.add(radioButton3);

      RootPanel.get("gwtContainer").add(panel);
   }	
}

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:

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