Question

I have two packages say com.android.package1 and com.android.package2
An activity in package1 (say A) wants to start an activity in package2 (say B)
To do this I used the following method

Intent to_start_B = new Intent(A.this,com.android.Package2.B.class);
startActivity(to_start_B);

This works fine for other activities, except for this (So no problems with manifest and call)!!

the code for this particular activity B is

public class B extends Activity {
private Logger logger = Logger.getMyLogger(this.getClass().getName());

private MicroRuntimeServiceBinder microRuntimeServiceBinder;
private ServiceConnection serviceConnection;

static final int CHAT_REQUEST = 0;
static final int SETTINGS_REQUEST = 1;

private MyReceiver myReceiver;
private MyHandler myHandler;

private TextView infoTextView;
private static String nickname="";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    myReceiver = new MyReceiver();

    IntentFilter killFilter = new IntentFilter();
    killFilter.addAction("jade.demo.chat.KILL");
    registerReceiver(myReceiver, killFilter);

    IntentFilter showChatFilter = new IntentFilter();
    showChatFilter.addAction("jade.demo.chat.SHOW_CHAT");
    registerReceiver(myReceiver, showChatFilter);

    myHandler = new MyHandler();
    nickname = "Ganesh";//getIntent().getExtras().getString("uname");

    setContentView(R.layout.chat_main);
    Button button = (Button) findViewById(R.id.btn_chatroom);
    button.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {
            // TODO Auto-generated method stub
            if (!checkName(nickname)) {
                logger.info("Invalid nickname!");
                myHandler.postError(getString(R.string.msg_nickname_not_valid));
            } else {
                try {
                    SharedPreferences settings = getSharedPreferences(
                            "jadeChatPrefsFile", 0);
                    String host = settings.getString("defaultHost", "");
                    String port = settings.getString("defaultPort", "");
                    infoTextView.setText(getString(R.string.msg_connecting_to)
                            + " " + host + ":" + port + "...");
                    startChat(nickname, host, port, agentStartupCallback);
                } catch (Exception ex) {
                    logger.severe("Unexpected exception creating chat agent!");
                    infoTextView.setText(getString(R.string.msg_unexpected));
                }
            }

        }
    });     
    infoTextView = (TextView) findViewById(R.id.infoTextView);
    infoTextView.setText("");

}

I am getting an error in following manner

03-07 11:36:25.399: W/dalvikvm(8493): threadid=1: thread exiting with uncaught exception (group=0x40015560)
03-07 11:36:25.409: E/AndroidRuntime(8493): FATAL EXCEPTION: main
03-07 11:36:25.409: E/AndroidRuntime(8493): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.home/chat.client.gui.MainActivity}: java.lang.NullPointerException
03-07 11:36:25.409: E/AndroidRuntime(8493):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at android.os.Looper.loop(Looper.java:123)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at android.app.ActivityThread.main(ActivityThread.java:3683)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at java.lang.reflect.Method.invokeNative(Native Method)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at java.lang.reflect.Method.invoke(Method.java:507)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
03-07 11:36:25.409: E/AndroidRuntime(8493):     at dalvik.system.NativeStart.main(Native Method)
03-07 11:36:25.409: E/AndroidRuntime(8493): Caused by: java.lang.NullPointerException
03-07 11:36:25.409: E/AndroidRuntime(8493):     at chat.client.gui.MainActivity.onCreate(MainActivity.java:96)
 03-07 11:36:25.409: E/AndroidRuntime(8493):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
 03-07 11:36:25.409: E/AndroidRuntime(8493):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
03-07 11:36:25.409: E/AndroidRuntime(8493):     ... 11 more

So basically its problem related to that particular activity B only.
But if it is executed as part of another application it works fine!

Can anyone please let me know how to get rid of this problem ?

Answer 1

Hey found a solution to my problem

While integrating my two packages from different projects, I had dragged and droped packages from src and gen folder (along with layouts).
So i had two copies of R file. But the pakage2.R file was invalid as a new R file was automatically generated with new R.id for each component in Package1 (in gen folder)
So the solution was

1. Remove Package2 from gen folder.
2. Import Package1.R file ineach file of Package2