ActionListener of Jbutton Question

Question

Hi there,
I am trying to perform a command via JButton by adding an ActionListener to the frame'instance' of my Pointframe:
public class MainClass {
  public static void main(String[] args)  {
  try {
  byte[] datasend = new byte[50];
  byte[] tempdatareceive= new byte[1000];
  int incomingPackageSize = 0;
  //create instance of GUI
  Pointframe frame = new Pointframe();
  frame.pack();
  frame.show();
  //add Action Listener stuff
      ActionListener SendStream = new ActionListener()
      public void actionPerformed( ActionEvent e ) {
      System.out.println("this works");
  frame.jButton1.addActionListener( SendStream );
  //create Socket to Connect to EmScon-Server
  Socket connectToEsServer = new Socket ("192.168.0.5",700);
  //create Output Stream to send data to Server
  DataOutputStream StreamtoEsServer
  = new DataOutputStream(connectToEsServer.getOutputStream());
  //create Input Stream to send data to Server
  DataInputStream StreamfromEsServer
  = new DataInputStream(connectToEsServer.getInputStream());
................Sending commands like above to the console works fine so far.
But as long as i start to try invoking variable relatedcommands.
public class MainClass {
  public static void main(String[] args)  {
  try {
  byte[] datasend = new byte[50];
  byte[] tempdatareceive= new byte[1000];
  int incomingPackageSize = 0;
  //create instance of GUI
  Pointframe frame = new Pointframe();
  frame.pack();
  frame.show();
  //add Action Listener stuff
      ActionListener SendStream = new ActionListener()
      public void actionPerformed( ActionEvent e ) {
     StreamtoEsServer.write(datasend);
  frame.jButton1.addActionListener( SendStream );
  //create Socket to Connect to EmScon-Server
  Socket connectToEsServer = new Socket ("192.168.0.5",700);
  //create Output Stream to send data to Server
  DataOutputStream StreamtoEsServer
  = new DataOutputStream(connectToEsServer.getOutputStream());
  //create Input Stream to send data to Server
  DataInputStream StreamfromEsServer
  = new DataInputStream(connectToEsServer.getInputStream());
................I receive errmessages like:
"MainClass.java": Error #: 480 : local variable datasend is accessed from within inner class; needs to be declared final
"MainClass.java": Error #: 300 : variable StreamtoEsServer not found in anonymous class of method main(java.lang.String[])
Can please somebody bring light into that?
What is the best way to implement such stuff in general?
Any ideas are greatly appreciated.
Best regards,
stonee

Answer 1

Hi,
try instantiaitng your variable datasend as private variable in the class outside your main-method