Updating graphics

Question

I surrender. Trying for some weeks now to find out what is blocking received serial data from being updated by the graphic part of my code. First time programming in Java. Have about 15 years of experience programming micros and I'm used to solve my own problems but this goes beyond the point where that tactic is productive. My application consist of two files.

One file stems from RXTX project and catch serial data sent in several packets twice every second. This works like a charm (took some time) and I can see that captured data is correct and stable.

The other file is graphic and consist of around 80 menus where end user can read and sometimes write values. Navigating is done with mouse events on buttons and scroll bar so far. This part also work as it should. Values can be read, changed and saved etc.

The part where I'm stuck is that updated values from serial file never update the graphic screen. Have tried to follow hundreds of examples and tutorials (many from this site) with no luck.

The concept of object related languages is new to me and still pretty confusing. Pretty sure my problem involves inheritance and classes. Threads is another candidate... Have cut down code to smallest size that still would run and present my problem and hope someone can see whats wrong.

package components;

import gnu.io.CommPort;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.swing.SwingUtilities;

public class SerialComm extends ScreenBuilder implements java.util.EventListener {

InputStream in;

public SerialComm() {
    super();
}

public interface SerialPortEventListener
        extends java.util.EventListener {
}

void connect(String portName) throws Exception {
    CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier("COM1");
    if (portIdentifier.isCurrentlyOwned()) {
        System.out.println("Error: Port is currently in use");
    } else {
        CommPortIdentifier.getPortIdentifier("COM1");
        System.out.println("" + portName);
        CommPort commPort = portIdentifier.open("COM1", 2000);
        if (commPort instanceof SerialPort) {
            SerialPort serialPort = (SerialPort) commPort;
            serialPort.setSerialPortParams(115200, SerialPort.DATABITS_8, SerialPort.STOPBITS_2, SerialPort.PARITY_NONE);
            InputStream in = serialPort.getInputStream();
            OutputStream out = serialPort.getOutputStream();
            serialPort.addEventListener(new SerialComm.SerialReader(in));
            serialPort.notifyOnDataAvailable(true);

            (new Thread(new SerialComm.SerialReader(in))).start();
            // TX functionality commented for now
            //               (new Thread(new SerialWriter(out))).start();

        } else {
            System.out.println("Error: Only serial ports are handled by this     example.");
        }
    }
}

public class SerialReader extends SerialComm implements Runnable,
        gnu.io.SerialPortEventListener {

    public SerialReader(InputStream in) {
        this.in = in;
    }

    @Override
    public void run() {
    count=11; // just for test. run is normally empty
    count2=count; // and real code runs within serialEvent()
    System.out.println("SerialReader " + count);
    dspUpdate(); // do some desperate stuff in graphics file
    System.out.println("Post Update " + count);
    }

    @Override
    public void serialEvent(SerialPortEvent event) {
    System.out.println("SerialEvent");
        switch (event.getEventType()) {
            case SerialPortEvent.DATA_AVAILABLE:
                try {
                    synchronized (in) {
                        while (in.available() < 0) {
                            in.wait(1, 800000);
                        } //in real code RX data is captured here twice a sec
                    } //and stored into buffers defined in ScreenBuilder
    //dspUpdate() is called from here to make ScreenBuilder update its screen
    //That never happens despite all my attempts               
                } catch (IOException e) {
                    System.out.println("IO Exception");
                } catch (InterruptedException e) {
                    System.out.println("InterruptedException caught");
                }
        }
    }
}

/* "main" connect PC serial port and start graphic part of application
 * To demonstrate problem with no serial data stream present
 * order of init between serial port and graphics are switched
 */

public static void main(String[] args) {

    SwingUtilities.invokeLater(new Runnable() {

        @Override
        public void run() {
            ScreenBuilder screen = new ScreenBuilder();
            screen.createAndShowGUI();
            System.out.println("Created GUI");
        }
    });
    try {
        (new SerialComm()).connect("COM1");
    } catch (Exception e) {
        System.out.println("Error");
        e.printStackTrace();
    }
  }
}

And the graphics file

package components;

import java.awt.*;
import javax.swing.SwingUtilities;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.*;

public class ScreenBuilder extends JPanel implements ActionListener {

public Font smallFont = new Font("Dialog", Font.PLAIN, 12);
Color screenColor;
Color lineColor;
short btn=0;
short count;
short count2;
Button helpButton;

public static void createAndShowGUI() {
    System.out.println("Created GUI on EDT? "
            + SwingUtilities.isEventDispatchThread());
    JFrame f = new JFrame("JUST A TEST");
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.add(new ScreenBuilder());
    f.pack();
    f.setVisible(true);
}

public void dspButton() {
    setLayout(null);// 
    helpButton = new Button("?");
    helpButton.setLocation(217, 8); // set X, Y
    helpButton.setSize(16, 14); //Set Size X, Y //
    helpButton.addActionListener(this);
    add(helpButton);
    setBackground(Color.black);
    helpButton.setBackground(Color.black);
    screenColor = Color.black;
    helpButton.setForeground(Color.white);
    lineColor = Color.white;
}

@Override
public void actionPerformed(ActionEvent e) {
    if (e.getSource() == helpButton) {
        count2++;
        System.out.println("Pressed Button ");
        repaint();
    }
}

public ScreenBuilder() {
    setBorder(BorderFactory.createLineBorder(Color.black));
}

@Override
public Dimension getPreferredSize() {
    return new Dimension(240, 180);
}

public void dspUpdate() {
    /*
     * This function is called from SerialComm
     * Should be called when serial packets have arrived (twice a second)
     * and update screen with values from serial stream
     * For now just a test var to validate that values from SerialComm
     * get to here (they do)
     */
count++;
System.out.println("Update Count " + count);
System.out.println("Update Count2 " + count2);
//    revalidate(); // another futile attempt to update screen
//    repaint();
}

@Override
public void paintComponent(Graphics g) {
    super.paintComponent(g);
    g.setColor(lineColor);
    g.setFont(smallFont);
    count++;
    g.drawString("" + count, 130, 20);
    g.drawString("" + count2, 150, 20);
    if (btn == 0) {
      dspButton();
      btn = 1;
    }
  }
}

Answer 1

The biggest problem you're running into is putting everything into the GUI classes. Try to separate your model (backend serial communication stuff) from your front end (pretty GUI stuff), and you'll save yourself a lot of headache. In the example I've tried to do that for you - it's in one file, but you should probably separate it into 3: Model, View, and Control (control is what communicates between model and view).

If you add your Serial Communication code (which you said was working) to the Model instead of the sample thread, you should be able to communicate between the view and model without too much hassle. I tried to preserve as much of your code as I could.

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

public class TranslucentWindow {

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                try {
                    View screen = new View();
                    System.out.println("Created GUI");
                    Model model = new Model();

                    Control c = new Control(screen, model);
                } catch (Exception e) {
                    System.out.println("Error");
                    e.printStackTrace();
                }
            }
        });
    }

    //Only cares about the backend.  Simplified because you said all the backend code was working right.
    public static class Model{

        //Data that was updated - you can change this to whatever you want.
        public String count;
        //Listener that notifies anyone interested that data changed
        public ActionListener refreshListener;

        public void run() {
            //As a sample, we're updating info every 1/2 sec.  But you'd have your Serial Listener stuff here
            Thread t = new Thread(new Runnable(){
                @Override
                public void run() {
                    int i = 0;
                    while(true){
                        dspUpdate(i++);
                        try {
                            Thread.sleep(500);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }});
            t.start();
        }

        //Update data and notify your listeners
        public void dspUpdate(int input) {
            count = String.valueOf(input);
            System.out.println("Update Count " + count);
            refreshListener.actionPerformed(new ActionEvent(this, input, "Update"));
        }

    }


    //Only cares about the display of the screen
    public static class View extends JPanel {

        public Font smallFont = new Font("Dialog", Font.PLAIN, 12);
        Color screenColor;
        Color lineColor;
        short btn=0;
        String modelRefreshInfo;
        int buttonPressCount;
        Button helpButton;

        public View(){
            //Build Panel
            dspButton();

            //Create and show window
            System.out.println("Created GUI on EDT? "+ SwingUtilities.isEventDispatchThread());
            JFrame f = new JFrame("JUST A TEST");
            f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            f.add(this);
            f.pack();
            f.setVisible(true);
        }

        public void dspButton() {
            setLayout(null);// 
            helpButton = new Button("?");
            helpButton.setLocation(217, 8); // set X, Y
            helpButton.setSize(16, 14); //Set Size X, Y //
            add(helpButton);
            setBackground(Color.black);
            helpButton.setBackground(Color.black);
            screenColor = Color.black;
            helpButton.setForeground(Color.white);
            lineColor = Color.white;
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(240, 180);
        }   

        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.setColor(lineColor);
            g.setFont(smallFont);
            g.drawString("ModelUpdates: " + modelRefreshInfo, 10, 20);
            g.drawString("RefreshCount: " + buttonPressCount, 10, 40);
            if (btn == 0) {
                dspButton();
                btn = 1;
            }
        }
    }

    //Links up the view and the model
    public static class Control{
        View screen;
        Model model;

        public Control(View screen, Model model){
            this.screen = screen;
            //Tells the screen what to do when the button is pressed
            this.screen.helpButton.addActionListener(new ActionListener(){
                @Override
                public void actionPerformed(ActionEvent e) {
                    //Update the screen with the model's info
                    Control.this.screen.buttonPressCount++;
                    System.out.println("Pressed Button ");
                    Control.this.screen.repaint();
                }
            });

            this.model = model;
            //Hands new data in the model to the screen
            this.model.refreshListener = new ActionListener(){
                @Override
                public void actionPerformed(ActionEvent e) {
                    //Update the screen with the model's info
                    Control.this.screen.modelRefreshInfo = Control.this.model.count;
                    System.out.println("Model Refreshed");
                    Control.this.screen.repaint();
                }
            };

            //Starts up the model
            this.model.run();
        }       
    }
}