setText in Java isn't working

Question

I'm learning in Java, and I'm trying do this settext work, but I'm not getting

public static void main(String args[]) throws Exception
{
    try {
        (new Visual()).connect("COM4", "1");
        (new Visual()).connect("COM6", "2");
    } catch ( Exception e ) {
        e.printStackTrace();
    }
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new Visual().setVisible(true);
        }
    });
}

void connect ( String portName, String linha ) throws Exception
{
    CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName);
    if ( portIdentifier.isCurrentlyOwned() )
    {
        System.out.println("Error: Port is currently in use");
    }
    else
    {
        CommPort commPort = portIdentifier.open(this.getClass().getName(),2000);

        if ( commPort instanceof SerialPort )
        {
            SerialPort serialPort = (SerialPort) commPort;
            serialPort.setSerialPortParams(57600,SerialPort.DATABITS_8,SerialPort.STOPBITS_1,SerialPort.PARITY_NONE);

            status_porta2.setText(portName);
            .....

        }
    }    
}

I'm searching change a label text in this function, but isn't working.. What are happening? Thanks

Answer 1

The problem is, you are creating multiple instances of Visual, two which you open a connection and one you show on the screen.

None of these have any connection to each other, meaning what's on the screen isn't what's being managed/manipulated.

Instead, the instance you use to connect to the port should be the instance you show...

For example...

public static void main(String args[]) throws Exception
{
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                Visual v1 = new Visual();
                v1.connect("COM4", "1");
                v1.setVisible(true);

                Visual v2 = new Visual();
                v2.connect("COM6", "2");
                v2.setVisible(true);
            } catch ( Exception e ) {
                e.printStackTrace();
            }
        }
    });
}