退出的时候出现Uncaught exception java.lang.NullPointerException.
帮帮忙看一下。
package com.mobile;
import javax.microedition.midlet.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;
import java.io.*;
public class SocketMIDlet extends MIDlet implements CommandListener {
private static final String SERVER = "Server ";
private static final String CLIENT = "Client ";
private static final String[] names = { SERVER, CLIENT };
private static Display display;
private Form f;
private ChoiceGroup cg;
private boolean isPaused;
private Server server;
private Client client;
private Command exitCommand = new Command( "Exit ", Command.EXIT, 1);
private Command startCommand = new Command( "Start ", Command.ITEM, 1);
public SocketMIDlet() {
display = Display.getDisplay(this);
f = new Form( "Socket Demo ");
cg = new ChoiceGroup( "Please select peer ", Choice.EXCLUSIVE, names,
null);
f.append(cg);
f.addCommand(exitCommand);
f.addCommand(startCommand);
f.setCommandListener(this);
display.setCurrent(f);
}
public boolean isPaused() {
return isPaused;
}
public void startApp() {
isPaused = false;
}
public void pauseApp() {
isPaused = true;
}
public void destroyApp(boolean unconditional) {
if (server != null) {
server.stop();
}
if (client != null) {
client.stop();
}
}
public void commandAction(Command c, Displayable s) {
if (c == exitCommand) {
destroyApp(true);
notifyDestroyed();
} else if (c == startCommand) {
String name = cg.getString(cg.getSelectedIndex());
if (SERVER.equals(name)) {
server = new Server(this);
server.start();
} else {
client = new Client(this);
client.start();
}
}
}
}
package com.mobile;
import javax.microedition.midlet.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;
import java.io.*;
public class Server implements Runnable, CommandListener {
private SocketMIDlet parent;
private Display display;
private Form f;
private StringItem si;
private TextField tf;
private boolean stop;
private Command sendCommand = new Command( "Send ", Command.ITEM, 1);
