Apps URGENT Help NEEDED WITH App CODE!! : java.lang.NullPointerException

[kumankit]

Hello everyone, I'm creating an app for chat client. This is my first app and i'm fairly new to java programming too. I am getting force close for this code. the logcat and the code are given below. kindly help me out. I relly cant figure this out myself.







package com.drive;


import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.NotificationManager;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.ServiceConnection;
import android.os.*;
import android.os.Handler;
import android.os.IBinder;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnKeyListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.drive.interfaces.IAppManager;
import com.drive.services.IMService;
import com.drive.tools.FriendController;
import com.drive.types.FriendInfo;

public class Messaging extends Activity {

private static final int MESSAGE_CANNOT_BE_SENT = 0;
private EditText messageText;
private EditText messageHistoryText;
private Button sendMessageButton;
private IAppManager imService;
private FriendInfo friend = new FriendInfo();

private ServiceConnection mConnection = new ServiceConnection() {

public void onServiceConnected(ComponentName className, IBinder service) {
imService = ((IMService.IMBinder)service).getService();
}
public void onServiceDisconnected(ComponentName className) {
imService = null;
Toast.makeText(com.drive.Messaging.this, R.string.local_service_stopped,
Toast.LENGTH_SHORT).show();
}
};

@Override
protected void onCreate(Bundle savedInstanceState)
{
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);

setContentView(R.layout.messaging_screen); //messaging_screen);

messageHistoryText = (EditText) findViewById(R.id.messageHistory);

messageText = (EditText) findViewById(R.id.message);

messageText.requestFocus();

sendMessageButton = (Button) findViewById(R.id.sendMessageButton);

Bundle extras = this.getIntent().getExtras();

friend.userName = extras.getString(FriendInfo.USERNAME);
friend.ip = extras.getString(FriendInfo.IP);
friend.port = extras.getString(FriendInfo.PORT);
String msg = extras.getString(FriendInfo.MESSAGE);


setTitle("Messaging with " + friend.userName);


// EditText friendUserName = (EditText) findViewById(R.id.friendUserName);
// friendUserName.setText(friend.userName);

if (msg != null)
{
this.appendToMessageHistory(friend.userName , msg);
((NotificationManager)getSystemService(NOTIFICATION_SERVICE)).cancel((friend.userName+msg).hashCode());
}

sendMessageButton.setOnClickListener(new OnClickListener(){
CharSequence message;
Handler handler = new Handler();
public void onClick(View arg0) {
message = messageText.getText();
if (message.length()>0)
{
appendToMessageHistory(imService.getUsername(), message.toString());

messageText.setText("");
Thread thread = new Thread(){
public void run() {
if (!imService.sendMessage(friend.userName, message.toString()))
{

handler.post(new Runnable(){

public void run() {
showDialog(MESSAGE_CANNOT_BE_SENT);
}

});
}
}
};
thread.start();

}

}});

messageText.setOnKeyListener(new OnKeyListener(){
public boolean onKey(View v, int keyCode, KeyEvent event)
{
if (keyCode == 66){
sendMessageButton.performClick();
return true;
}
return false;
}


});

}

@Override
protected Dialog onCreateDialog(int id) {
int message = -1;
switch (id)
{
case MESSAGE_CANNOT_BE_SENT:
message = R.string.message_cannot_be_sent;
break;
}

if (message == -1)
{
return null;
}
else
{
return new AlertDialog.Builder(Messaging.this)
.setMessage(message)
.setPositiveButton(R.string.OK, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
/* User clicked OK so do some stuff */
}
})
.create();
}
}

@Override
protected void onPause() {
super.onPause();
unregisterReceiver(messageReceiver);
unbindService(mConnection);

FriendController.setActiveFriend(null);

}

@Override
protected void onResume()
{
super.onResume();
bindService(new Intent(Messaging.this, IMService.class), mConnection , Context.BIND_AUTO_CREATE);

IntentFilter i = new IntentFilter();
i.addAction(IMService.TAKE_MESSAGE);

registerReceiver(messageReceiver, i);

FriendController.setActiveFriend(friend.userName);



}


public class MessageReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent)
{
Bundle extra = intent.getExtras();
String username = extra.getString(FriendInfo.USERNAME);
String message = extra.getString(FriendInfo.MESSAGE);

if (username != null && message != null)
{
if (friend.userName.equals(username)) {
appendToMessageHistory(username, message);
}
else {
if (message.length() > 15) {
message = message.substring(0, 15);
}
Toast.makeText(Messaging.this, username + " says '"+
message + "'",
Toast.LENGTH_SHORT).show();
}
}
}

};
private MessageReceiver messageReceiver = new MessageReceiver();

private void appendToMessageHistory(String username, String message) {
if (username != null && message != null) {
messageHistoryText.append(username + ":\n");
messageHistoryText.append(message + "\n");
}
}





}





04-27 02:06:40.870: E/AndroidRuntime(222): Uncaught handler: thread main exiting due to uncaught exception
04-27 02:06:40.901: E/AndroidRuntime(222): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.drive/com.drive.Messaging}: java.lang.NullPointerException
04-27 02:06:40.901: E/AndroidRuntime(222): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
04-27 02:06:40.901: E/AndroidRuntime(222): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
04-27 02:06:40.901: E/AndroidRuntime(222): at android.app.ActivityThread.access$2200(ActivityThread.java:119)
04-27 02:06:40.901: E/AndroidRuntime(222): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
04-27 02:06:40.901: E/AndroidRuntime(222): at android.os.Handler.dispatchMessage(Handler.java:99)
04-27 02:06:40.901: E/AndroidRuntime(222): at android.os.Looper.loop(Looper.java:123)
04-27 02:06:40.901: E/AndroidRuntime(222): at android.app.ActivityThread.main(ActivityThread.java:4363)
04-27 02:06:40.901: E/AndroidRuntime(222): at java.lang.reflect.Method.invokeNative(Native Method)
04-27 02:06:40.901: E/AndroidRuntime(222): at java.lang.reflect.Method.invoke(Method.java:521)
04-27 02:06:40.901: E/AndroidRuntime(222): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
04-27 02:06:40.901: E/AndroidRuntime(222): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
04-27 02:06:40.901: E/AndroidRuntime(222): at dalvik.system.NativeStart.main(Native Method)
04-27 02:06:40.901: E/AndroidRuntime(222): Caused by: java.lang.NullPointerException
04-27 02:06:40.901: E/AndroidRuntime(222): at com.drive.Messaging.onCreate(Messaging.java:70)
04-27 02:06:40.901: E/AndroidRuntime(222): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
04-27 02:06:40.901: E/AndroidRuntime(222): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
04-27 02:06:40.901: E/AndroidRuntime(222): ... 11 more
04-27 02:06:40.930: E/dalvikvm(222): Unable to open stack trace file '/data/anr/traces.txt': Permission denied

 

[Unforgiven]

I've moved this to our applications development forum so you can get some better eyeballs on your question.

 

[Rukbat]

NullPointerException usually means that you created a variable, failed to initialize it to any value, then used itas a pointer. You can't do that.

 

[LolaKima]

Please if you have found a solution for this problem please share it since I have the same problem and I can not fix it.
thank you in advance

 

[uwe]

check if extras is null in onCreate