Java Swing: JTextField, JtextArea.

Java JTextField

The object of a JTextField class is a text component that allows the editing of a single line text. It inherits JTextComponent class.

JTextField class declaration

Let's see the declaration for javax.swing.JTextField class.

1. public class JTextField extends JTextComponent implements SwingConstants  

Commonly used Constructors:

Constructor	Description
JTextField()	Creates a new TextField
JTextField(String text)	Creates a new TextField initialized with the specified text.
JTextField(String text, int columns)	Creates a new TextField initialized with the specified text and columns.
JTextField(int columns)	Creates a new empty TextField with the specified number of columns.

---

Commonly used Methods:

Methods	Description
void addActionListener(ActionListener l)	It is used to add the specified action listener to receive action events from this textfield.
Action getAction()	It returns the currently set Action for this ActionEvent source, or null if no Action is set.
void setFont(Font f)	It is used to set the current font.
void removeActionListener(ActionListener l)	It is used to remove the specified action listener so that it no longer receives action events from this textfield.

Java JTextField Example

1. import javax.swing.*;  
2. class TextFieldExample  
3. {  
4. public static void main(String args[])  
5.     {  
6.     JFrame f= new JFrame("TextField Example");  
7.     JTextField t1,t2;  
8.     t1=new JTextField("Welcome to Javatpoint.");  
9.     t1.setBounds(50,100, 200,30);  
10.     t2=new JTextField("AWT Tutorial");  
11.     t2.setBounds(50,150, 200,30);  
12.     f.add(t1); f.add(t2);  
13.     f.setSize(400,400);  
14.     f.setLayout(null);  
15.     f.setVisible(true);  
16.     }  
17.     }  

Output:

---

Java JTextField Example with ActionListener

1. import javax.swing.*;  
2. import java.awt.event.*;  
3. public class TextFieldExample implements ActionListener{  
4.     JTextField tf1,tf2,tf3;  
5.     JButton b1,b2;  
6.     TextFieldExample(){  
7.         JFrame f= new JFrame();  
8.         tf1=new JTextField();  
9.         tf1.setBounds(50,50,150,20);  
10.         tf2=new JTextField();  
11.         tf2.setBounds(50,100,150,20);  
12.         tf3=new JTextField();  
13.         tf3.setBounds(50,150,150,20);  
14.         tf3.setEditable(false);   
15.         b1=new JButton("+");  
16.         b1.setBounds(50,200,50,50);  
17.         b2=new JButton("-");  
18.         b2.setBounds(120,200,50,50);  
19.         b1.addActionListener(this);  
20.         b2.addActionListener(this);  
21.         f.add(tf1);f.add(tf2);f.add(tf3);f.add(b1);f.add(b2);  
22.         f.setSize(300,300);  
23.         f.setLayout(null);  
24.         f.setVisible(true);  
25.     }         
26.     public void actionPerformed(ActionEvent e) {  
27.         String s1=tf1.getText();  
28.         String s2=tf2.getText();  
29.         int a=Integer.parseInt(s1);  
30.         int b=Integer.parseInt(s2);  
31.         int c=0;  
32.         if(e.getSource()==b1){  
33.             c=a+b;  
34.         }else if(e.getSource()==b2){  
35.             c=a-b;  
36.         }  
37.         String result=String.valueOf(c);  
38.         tf3.setText(result);  
39.     }  
40. public static void main(String[] args) {  
41.     new TextFieldExample();  
42. } }  

Output:

Java JTextArea

The object of a JTextArea class is a multi line region that displays text. It allows the editing of multiple line text. It inherits JTextComponent class

JTextArea class declaration

Let's see the declaration for javax.swing.JTextArea class.

1. public class JTextArea extends JTextComponent  

Commonly used Constructors:

Constructor	Description
JTextArea()	Creates a text area that displays no text initially.
JTextArea(String s)	Creates a text area that displays specified text initially.
JTextArea(int row, int column)	Creates a text area with the specified number of rows and columns that displays no text initially.
JTextArea(String s, int row, int column)	Creates a text area with the specified number of rows and columns that displays specified text.

---

Commonly used Methods:

Methods	Description
void setRows(int rows)	It is used to set specified number of rows.
void setColumns(int cols)	It is used to set specified number of columns.
void setFont(Font f)	It is used to set the specified font.
void insert(String s, int position)	It is used to insert the specified text on the specified position.
void append(String s)	It is used to append the given text to the end of the document.

Java JTextArea Example

1. import javax.swing.*;  
2. public class TextAreaExample  
3. {  
4.      TextAreaExample(){  
5.         JFrame f= new JFrame();  
6.         JTextArea area=new JTextArea("Welcome to javatpoint");  
7.         area.setBounds(10,30, 200,200);  
8.         f.add(area);  
9.         f.setSize(300,300);  
10.         f.setLayout(null);  
11.         f.setVisible(true);  
12.      }  
13. public static void main(String args[])  
14.     {  
15.    new TextAreaExample();  
16.     }}  

Output:

---

Java JTextArea Example with ActionListener

1. import javax.swing.*;  
2. import java.awt.event.*;  
3. public class TextAreaExample implements ActionListener{  
4. JLabel l1,l2;  
5. JTextArea area;  
6. JButton b;  
7. TextAreaExample() {  
8.     JFrame f= new JFrame();  
9.     l1=new JLabel();  
10.     l1.setBounds(50,25,100,30);  
11.     l2=new JLabel();  
12.     l2.setBounds(160,25,100,30);  
13.     area=new JTextArea();  
14.     area.setBounds(20,75,250,200);  
15.     b=new JButton("Count Words");  
16.     b.setBounds(100,300,120,30);  
17.     b.addActionListener(this);  
18.     f.add(l1);f.add(l2);f.add(area);f.add(b);  
19.     f.setSize(450,450);  
20.     f.setLayout(null);  
21.     f.setVisible(true);  
22. }  
23. public void actionPerformed(ActionEvent e){  
24.     String text=area.getText();  
25.     String words[]=text.split("\\s");  
26.     l1.setText("Words: "+words.length);  
27.     l2.setText("Characters: "+text.length());  
28. }  
29. public static void main(String[] args) {  
30.     new TextAreaExample();  
31. }  
32. }  

Output:

Anurag Rana Educator CSE/IT