Unit 6: Exploring Swing

5th Semester

6.2 JTextField

JTextField is used for taking input of single line of text. It is most widely used text component. It has three constructors,

JTextField(int cols)
JTextField(String str, int cols)
JTextField(String str)

 

xample using JTextField

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class MyTextField extends JFrame
{
 public MyTextField()
 {
  JTextField jtf = new JTextField(20);	//creating JTextField.
  add(jtf);				//adding JTextField to frame.
  setLayout(new FlowLayout());
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setSize(400, 400);
  setVisible(true);
 }
 public static void main(String[] args)
 {
  new MyTextField();
 }
}

6.3 JButton

JButton class provides functionality of a button. JButton class has three constuctors,

JButton(Icon ic)
JButton(String str)
JButton(String str, Icon ic)

It allows a button to be created using icon, a string or both. JButton supports ActionEvent. When a button is pressed an ActionEvent is generated.
Example

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class testswing extends JFrame
{
 testswing()
 {
  JButton bt1 = new JButton("Yes");		//Creating a Yes Button.
  JButton bt2 = new JButton("No");		//Creating a No Button.
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE)     //setting close operation.
  setLayout(new FlowLayout());		//setting layout using FlowLayout object
  setSize(400, 400);			//setting size of Jframe
  add(bt1);		//adding Yes button to frame.
  add(bt2);		//adding No button to frame.
  setVisible(true);
 }
 public static void main(String[] args)
 {
  new testswing();
 }
}


 

6.5 JCheckBox

JCheckBox class is used to create checkboxes in frame. Following is constructor for JCheckBox,

JCheckBox(String str)

Example using JCheckBox

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class Test extends JFrame
{
 public Test()
 {
  JCheckBox jcb = new JCheckBox("yes");   //creating JCheckBox.
  add(jcb);				  //adding JCheckBox to frame.
  jcb = new JCheckBox("no");		  //creating JCheckBox.
  add(jcb);				  //adding JCheckBox to frame.
  jcb = new JCheckBox("maybe");		  //creating JCheckBox.
  add(jcb);				  //adding JCheckBox to frame.
  setLayout(new FlowLayout());
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setSize(400, 400);
  setVisible(true);
 }
 public static void main(String[] args)
 {
  new Test();
 }
}

6.5 JRadioButton

Radio button is a group of related button in which only one can be selected. JRadioButton class is used to create a radio button in Frames. Following is the constructor for JRadioButton,

JRadioButton(String str)

Example using JRadioButton

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class Test extends JFrame
{
 public Test()
 {
  JRadioButton jcb = new JRadioButton("A");	//creating JRadioButton.
  add(jcb);					//adding JRadioButton to frame.
  jcb = new JRadioButton("B");			//creating JRadioButton.
  add(jcb);					//adding JRadioButton to frame.
  jcb = new JRadioButton("C");			//creating JRadioButton.
  add(jcb);					//adding JRadioButton to frame.
  jcb = new JRadioButton("none");
  add(jcb);
  setLayout(new FlowLayout());
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setSize(400, 400);
  setVisible(true);
 }
 public static void main(String[] args)
 {
  new Test();
 }
}

6.9 JComboBox

Combo box is a combination of text fields and drop-down list.JComboBox component is used to create a combo box in Swing. Following is the constructor for JComboBox,

JComboBox(String arr[])

Example using JComboBox

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class Test extends JFrame
{
 String name[] = {"Abhi","Adam","Alex","Ashkay"};  //list of name.
 public Test()
 {
  JComboBox jc = new JComboBox(name);	//initialzing combo box with list of name.
  add(jc);				//adding JComboBox to frame.
  setLayout(new FlowLayout());
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setSize(400, 400);
  setVisible(true);
 }
 public static void main(String[] args)
 {
  new Test();
 }
}