I'm trying to make a button to count characters in a text field

Question

I'm trying to use the JButton count to count the number of characters entered into the JTextField t. I'm new to Java and GUIs but here's my code:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class GUI1 extends Frame implements ActionListener{

    TextField t; 
    Button count;
    int a;
    Choice choice;

    public GUI1(){

        this.t = new TextField("", 30);

        this.count = new Button("count");
        this.count.addActionListener(this);

        JTextField x = new JTextField();
        x.setEditable(false);

        this.setTitle("Character count");
        this.setLayout(new FlowLayout());

        this.add(x);
        this.add(t);
        this.add(count);

        this.pack();
        this.setVisible(true);

    }

    public void actionPerformed(ActionEvent e) {
        if(e.getSource()== this.count) 


       t.setText(choice.getSelectedItem()+ " " +a);
    }

I'm also trying to enter the value in another uneditable JTextField x. Any help is appreciated.

Raza Ali Poonja · Answer 1 · 2015-11-25T15:08:22.187

3

Add this to your code

count.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
    a = t.getText().length();
 }
});

OR

You can use lambda expression like this

count.addActionListener(e -> a = t.getText().length());

For More http://docs.oracle.com/javase/7/docs/api/java/awt/event/ActionListener.html

edited Nov 25 '15 at 15:08

answered Nov 25 '15 at 15:02

Raza Ali Poonja

1,086
8
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score 2 · Answer 2 · answered Nov 25 '15 at 14:58

You need to add a listener

TextField t = new TextField();

Button b = new Button("Count");
b.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        int count = t.getText().length();
     }
});

You can read more about here

http://www.tutorialspoint.com/awt/awt_button.htm

score 1 · Accepted Answer · edited May 23 '17 at 11:48

First of all, I recommend you not to use AWT elements, since it brings tons of problems and it has little to no support, instead you can try using Swing components which are a replacement/fix for AWT. You can read more about here. You might also want to read AWT vs Swing (Pros and Cons).

Now going into your problem:

You should avoid extending from JFrame, I might recommend you to create a new JFrame object instead. Here's the reason to why. That being said, you can also remove all your this.t and other calls with this.

I'm glad you're using a Layout Manager!

And now to count the number of characters on your JTextField and set text to your other JTextField you should use this code:

count.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        int count = t.getText().length();
        System.out.println(count);
        x.setText(t.getText());
    }
});

Also I fixed your code, I changed AWT elements to Swing ones and added number of cols to your second JTextField so it would appear.

So, here's a running example that I made from your code (And removed Choice choice line since you didn't posted that code):

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class GUI1 {

    JTextField t; 
    JButton count;
    int a;
    JFrame frame;

    public GUI1(){
        frame = new JFrame();
        t = new JTextField("", 15);
        count = new JButton("count");
        JTextField x = new JTextField("", 15);
        x.setEditable(false);

        count.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                int count = t.getText().length();
                System.out.println(count);
                x.setText(t.getText());
            }
        });

        frame.setTitle("Character count");
        frame.setLayout(new FlowLayout());

        frame.add(x);
        frame.add(t);
        frame.add(count);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);

    }

    public static void main (String args[]) {
        new GUI1();
    }
}

score 0 · Answer 4 · answered Nov 25 '15 at 15:03

When you click on a button you should

String str = t.getText(); // get string from jtextfield

To save the text from the texfield. Then you can use something like:

a = str..length(); // get length of string
x.setText(str + " " + a); //set it to the field

To set it to the JTextField.

I'm trying to make a button to count characters in a text field

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