Update JLabel every X seconds from ArrayList - Java

Question

I have a simple Java program that reads in a text file, splits it by \" \" (spaces), displays the first word, waits 2 seconds, displays the next... etc... I would like to do

Answer 1

First, build and display your GUI. Once the GUI is displayed, use a javax.swing.Timer to update the GUI every 500 millis:

final Timer timer = new Timer(500, null);
ActionListener listener = new ActionListsner() {
    private Iterator<Word> it = words.iterator();
    @Override 
    public void actionPerformed(ActionEvent e) {
        if (it.hasNext()) {
            label.setText(it.next().getName());
        }
        else {
            timer.stop();
        }
    }
};
timer.addActionListener(listener);
timer.start();

Answer 2

    import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;

import javax.swing.*;


class TimeThis extends JFrame {

    private static final long serialVersionUID = 1L;
    private ArrayList<Word> words;
    private JTextField _textField;  // set by timer listener

    public TimeThis() throws IOException {

        _textField = new JTextField(5);
        _textField.setEditable(false);
        _textField.setFont(new Font("sansserif", Font.PLAIN, 30));

        JPanel content = new JPanel();
        content.setLayout(new FlowLayout());
        content.add(_textField); 

        this.setContentPane(content);
        this.setTitle("Swing Timer");
        this.pack();
        this.setLocationRelativeTo(null);
        this.setResizable(false);
        _textField.setText("loading...");

        readFile(); // read file
        printWords(); // print results
    }

    public void readFile(){

        try {
            BufferedReader in = new BufferedReader(new FileReader("adameve.txt"));
            words = new ArrayList<Word>();
            int lineNum = 1; // we read first line in start

            // delimeters of line in this example only "space"
            char [] parse = {' '};
            String delims = new String(parse);

            String line = in.readLine();
            String [] lineWords = line.split(delims);

            // split the words and create word object
            //System.out.println(lineWords.length);

            for (int i = 0; i < lineWords.length; i++) {
                Word w = new Word(lineWords[i]); 
                words.add(w);                                      
            }
            lineNum++;    // pass the next line

            line = in.readLine();

            in.close();

        } catch (IOException e) {
        }
    }
    private void printWords() {
            final Timer timer = new Timer(100, null);

            ActionListener listener = new ActionListener() {
                private Iterator<Word> w = words.iterator();
                @Override 
                public void actionPerformed(ActionEvent e) {
                    if (w.hasNext()) {
                        _textField.setText(w.next().getName());
                        //Prints to Console just Fine...
                        //System.out.println(w.next().getName());   
                    }
                    else {
                        timer.stop();
                    }
                }
            };
            timer.addActionListener(listener);
            timer.start();

    }
    class Word{
        private String name;

        public Word(String name) {
            this.name = name;
        }
        public String getName() {
            return name;
        }    
    }   

    public static void main(String[] args) throws IOException {
        JFrame ani = new TimeThis();
        ani.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        ani.setVisible(true); 

    }
}

I got it working with this code... Hope it can help someone else expand on their Java knowledge. Also, if anyone has any recommendations on cleaning this up. Please do so!

Answer 3

You're on the right track, but you're creating the frame's inside the loop, not outside. Here's what it should be like:

private void printWords() {
    JFrame frame = new JFrame("Run Text File"); 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    JLabel textLabel = new JLabel("", SwingConstants.CENTER);
    textLabel.setPreferredSize(new Dimension(300, 100)); 
    frame.getContentPane().add(textLabel, BorderLayout.CENTER);
    //Display the window. frame.setLocationRelativeTo(null); 
    frame.pack(); 
    frame.setVisible(true);

    for (int i = 0; i < words.size(); i++) {
        //How many words?
        //System.out.print(words.size());
        //print each word on a new line...
        Word w = words.get(i);
        System.out.println(w.name);

        //pause between each word.
        try{
            Thread.sleep(500);
        } 
        catch(InterruptedException e){
            e.printStackTrace();
        }
        textLabel.setTest(w.name);
    }
}

Answer 4

Never use Thread.sleep(int) inside Swing Code, because it blocks the EDT; more here,

The result of using Thread.sleep(int) is this:

When Thread.sleep(int) ends

Example code:

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Random;
import javax.swing.*;
//http://stackoverflow.com/questions/7943584/update-jlabel-every-x-seconds-from-arraylistlist-java
public class ButtonsIcon extends JFrame implements Runnable {

    private static final long serialVersionUID = 1L;
    private Queue<Icon> iconQueue = new LinkedList<Icon>();
    private JLabel label = new JLabel();
    private Random random = new Random();
    private JPanel buttonPanel = new JPanel();
    private JPanel labelPanel = new JPanel();
    private Timer backTtimer;
    private Timer labelTimer;
    private JLabel one = new JLabel("one");
    private JLabel two = new JLabel("two");
    private JLabel three = new JLabel("three");
    private final String[] petStrings = {"Bird", "Cat", "Dog",
        "Rabbit", "Pig", "Fish", "Horse", "Cow", "Bee", "Skunk"};
    private boolean runProcess = true;
    private int index = 1;
    private int index1 = 1;

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                ButtonsIcon t = new ButtonsIcon();
            }
        });
    }

    public ButtonsIcon() {
        iconQueue.add(UIManager.getIcon("OptionPane.errorIcon"));
        iconQueue.add(UIManager.getIcon("OptionPane.informationIcon"));
        iconQueue.add(UIManager.getIcon("OptionPane.warningIcon"));
        iconQueue.add(UIManager.getIcon("OptionPane.questionIcon"));

        one.setFont(new Font("Dialog", Font.BOLD, 24));
        one.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        two.setFont(new Font("Dialog", Font.BOLD, 24));
        two.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        three.setFont(new Font("Dialog", Font.BOLD, 10));
        three.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        labelPanel.setLayout(new GridLayout(0, 3, 4, 4));

        labelPanel.add(one);
        labelPanel.add(two);
        labelPanel.add(three);
        //labelPanel.setBorder(new LineBorder(Color.black, 1));
        labelPanel.setOpaque(false);

        JButton button0 = createButton();
        JButton button1 = createButton();
        JButton button2 = createButton();
        JButton button3 = createButton();

        buttonPanel.setLayout(new GridLayout(0, 4, 4, 4));
        buttonPanel.add(button0);
        buttonPanel.add(button1);
        buttonPanel.add(button2);
        buttonPanel.add(button3);
        //buttonPanel.setBorder(new LineBorder(Color.black, 1));
        buttonPanel.setOpaque(false);

        label.setLayout(new BorderLayout());
        label.add(labelPanel, BorderLayout.NORTH);
        label.add(buttonPanel, BorderLayout.SOUTH);
        Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
        label.setPreferredSize(new Dimension(d.width / 3, d.height / 3));

        add(label, BorderLayout.CENTER);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
        setVisible(true);
        startBackground();
        startLabel2();
        new Thread(this).start();
        printWords(); // generating freeze Swing GUI durring EDT
    }

    private JButton createButton() {
        JButton button = new JButton();
        button.setBorderPainted(false);
        button.setBorder(null);
        button.setFocusable(false);
        button.setMargin(new Insets(0, 0, 0, 0));
        button.setContentAreaFilled(false);
        button.setIcon(nextIcon());
        button.setRolloverIcon(nextIcon());
        button.setPressedIcon(nextIcon());
        button.setDisabledIcon(nextIcon());
        nextIcon();
        return button;
    }

    private Icon nextIcon() {
        Icon icon = iconQueue.peek();
        iconQueue.add(iconQueue.remove());
        return icon;
    }

    // Update background at 4/3 Hz
    private void startBackground() {
        backTtimer = new javax.swing.Timer(750, updateBackground());
        backTtimer.start();
        backTtimer.setRepeats(true);
    }

    private Action updateBackground() {
        return new AbstractAction("Background action") {

            private static final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent e) {
                label.setIcon(new ImageIcon(getImage()));
            }
        };
    }

    // Update Label two at 2 Hz
    private void startLabel2() {
        labelTimer = new javax.swing.Timer(500, updateLabel2());
        labelTimer.start();
        labelTimer.setRepeats(true);
    }

    private Action updateLabel2() {
        return new AbstractAction("Label action") {

            private static final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent e) {
                two.setText(petStrings[index]);
                index = (index + 1) % petStrings.length;
            }
        };
    }

    // Update lable one at 3 Hz
    @Override
    public void run() {
        while (runProcess) {
            SwingUtilities.invokeLater(new Runnable() {

                @Override
                public void run() {
                    one.setText(petStrings[index1]);
                    index1 = (index1 + 1) % petStrings.length;
                }
            });
            try {
                Thread.sleep(300);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    // Note: blocks EDT
    private void printWords() {
        for (int i = 0; i < petStrings.length; i++) {
            String word = petStrings[i].toString();
            System.out.println(word);
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            three.setText(word);
        }
        three.setText("<html> Concurency Issues in Swing<br>"
                + " never to use Thread.sleep(int) <br>"
                + " durring EDT, simple to freeze GUI </html>");
    }

    public BufferedImage getImage() {
        int w = label.getWidth();
        int h = label.getHeight();
        GradientPaint gp = new GradientPaint(0f, 0f, new Color(
                127 + random.nextInt(128),
                127 + random.nextInt(128),
                127 + random.nextInt(128)),
                w, w,
                new Color(random.nextInt(128), random.nextInt(128), random.nextInt(128)));
        BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2d = bi.createGraphics();
        g2d.setPaint(gp);
        g2d.fillRect(0, 0, w, h);
        g2d.setColor(Color.BLACK);
        return bi;
    }
}