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Thread: Button question

  1. #1
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    Default Button question

    I have a button, start, that starts a countdown timer. While the timer is counting down the button stays pressed. I need to be able to press another button, stop, while the timer is counting down.


  2. #2
    Administrator copeg's Avatar
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    Default Re: Button question

    You need to post an SSCCE that demonstrates the problem, and clearly define what the problem actually is because - while I might be the only one - I do not even know what the question is.

  3. #3
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    Default Re: Button question

    import javax.swing.*;

    import java.awt.*;
    import java.awt.event.*;
    import java.text.SimpleDateFormat;
    import java.util.Date;
    import java.util.Scanner;

    public class MicrowaveWindow extends JFrame implements KeyListener{

    // Declaring variables
    private JPanel east = null;
    private JPanel south = null;
    private static JPanel north = null;
    private JLabel screen = null;
    public static JPanel center = new JPanel();
    public static String secString = null;
    public static String minString = null;
    public static int stopping;

    // Constructing the window
    public MicrowaveWindow() {
    setTitle("Microwave Interface");
    setSize(600,400);
    setVisible(true);

    east = new JPanel();
    add(east, BorderLayout.EAST);
    screen = new JLabel("");
    east.add(screen);
    east.setLayout(new GridLayout(4,3));

    south = new JPanel();
    add(south, BorderLayout.SOUTH);
    south.add(screen);

    north = new JPanel();
    add(north, BorderLayout.NORTH);
    north.add(screen);

    center.setLayout(new GridLayout(4, 3));
    add(center);
    center.setBackground(Color.LIGHT_GRAY);

    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );
    this.addKeyListener(this);


    // Constructing buttons
    JButton[] nButtons = new JButton[10];
    for(int i = 0; i < nButtons.length; i++) {
    nButtons[i] = new JButton("" + i);
    nButtons[i].addActionListener(new NumAction());
    nButtons[i].addKeyListener(this);
    }
    for(int i = 0; i < 9; i++) {
    east.add(nButtons[i + 1]);

    }

    JButton stop = new JButton("Stop");
    east.add(stop);

    east.add(nButtons[0]);

    final JButton start = new JButton("Start");
    east.add(start);

    JButton open = new JButton("Open");
    south.add(open);


    // Key press events

    start.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent ae) {
    System.out.println("Start");
    center.setBackground(Color.YELLOW);
    start.setEnabled(true);
    Timer(minutes, seconds);

    }
    });


    stop.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent ae) {
    System.out.println("Stop");
    center.setBackground(Color.LIGHT_GRAY);
    timeLabel.setText(sdf.format(0000));
    q="0";w="0";e="0";r="0";
    }
    });

    open.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent ae) {
    System.out.println("Open");
    center.setBackground(Color.LIGHT_GRAY);
    }
    });
    }

    //unnecessary code
    public void keyPressed(KeyEvent ke) {}
    public void keyReleased(KeyEvent ke) {}

    public void keyTyped(KeyEvent ke) {
    addNum("" + ke.getKeyChar());
    }


    // NumAction class

    private class NumAction implements ActionListener {
    public void actionPerformed(ActionEvent event) {
    String text = event.getActionCommand();
    addNum(text);
    }
    }

    // Reading in the numbers
    public static String q="0";
    public static String w="0";
    public static String e="0";
    public static String r="0";
    public static int seconds=0;
    public static int minutes=0;
    public static JLabel timeLabel = new JLabel();
    static SimpleDateFormat sdf = new SimpleDateFormat("mm:ss");

    public void addNum(String text) {


    String clockset = screen.getText();
    clockset += text;
    r=e;
    e=w;
    w=q;
    q=clockset;

    timeLabel.setText(r+e+":"+w+q);



    int rInt = Integer.parseInt(r);
    int eInt = Integer.parseInt(e);
    int wInt = Integer.parseInt(w);
    int qInt = Integer.parseInt(q);
    seconds = wInt*10 + qInt;
    minutes = rInt*10 + eInt;

    }

    // Running the timer method

    // Main methods
    public static void main(String[] args) {
    JFrame f = new MicrowaveWindow();
    f.setVisible(true);
    north.add(timeLabel);
    timeLabel.setText(sdf.format(0000));

    }


    public static void Timer(int counter2, int counter){
    for(int i = 0; counter>0; i++){

    counter--;

    secString = Integer.toString(counter);
    minString = Integer.toString(counter2);

    if(counter<=9){
    secString = "0" + secString;
    }
    if(counter2<=9){
    minString = "0" + minString;
    }
    System.out.print(minString);
    System.out.println(secString);


    // countdown display


    timeLabel.setText(minString + ":" + secString);


    if(counter<=0){
    counter = 60;
    counter2--;
    if(minString.equals("00") && secString.equals("00")){
    break;
    }
    }

    try {
    Thread.sleep(1000);
    } catch (InterruptedException e) {

    e.printStackTrace();
    }
    }
    timeLabel.setText(sdf.format(0000));
    q="0";w="0";e="0";r="0";
    center.setBackground(Color.LIGHT_GRAY);
    }











    public void actionPerformed(ActionEvent arg0) {
    // TODO Auto-generated method stub

    }
    }

  4. #4
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    Default Re: Button question

    For future reference, please wrap your code in the code tags (see the forum rules for instructions)

    Swing is single threaded...all updates, painting, etc...occurs on this one thread called the EDT. Your code attempts to perform computation and timer tasks on the EDT (from within the actionPerformed method), and until this is complete no Swing component will be updated. If you wish to perform long running tasks, use another Thread (requires management to dispatch updates to the EDT) or a Swing Timer.

    See Lesson: Concurrency in Swing (The Java™ Tutorials > Creating a GUI With JFC/Swing)

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