为什么此活动意外关闭了我的Android？

Question

What this code does is that it registers the user to the server for gcm and to my server to add in the mysql database. It also writes into user preference. The app unexpectedly stops after it completes creating the user on the gcm server as well as my server. Please help me out?

package com.package.name;
import static com.package.name.CommonUtilities.SENDER_ID;
import static com.package.name.CommonUtilities.SERVER_URL;

import java.util.Random;

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class RegisterActivity extends Activity {
// alert dialog manager
AlertDialogManager alert = new AlertDialogManager();

// Internet detector
ConnectionDetector cd;

// UI elements
EditText txtName;
EditText txtEmail;

// Register button
Button btnRegister;

// Session Manager Class
SessionManager session;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);

    // Session Manager
    session = new SessionManager(getApplicationContext()); 

    cd = new ConnectionDetector(getApplicationContext());

    session.checkLogin();

    // Check if Internet present
    if (!cd.isConnectingToInternet()) {
        // Internet Connection is not present
        alert.showAlertDialog(RegisterActivity.this,
                "Internet Connection Error",
                "Please connect to working Internet connection", false);
        // stop executing code by return
        return;
    }

    // Check if GCM configuration is set
    if (SERVER_URL == null || SENDER_ID == null || SERVER_URL.length() == 0
            || SENDER_ID.length() == 0) {
        // GCM sernder id / server url is missing
        alert.showAlertDialog(RegisterActivity.this, "Configuration Error!",
                "Please set your Server URL and GCM Sender ID", false);
        // stop executing code by return
         return;
    }

    txtName = (EditText) findViewById(R.id.txtName);
    txtEmail = (EditText) findViewById(R.id.txtEmail);
    btnRegister = (Button) findViewById(R.id.btnRegister);

    /*
     * Click event on Register button
     * */
    btnRegister.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // Read EditText dat
            String name = txtName.getText().toString();
            String email = txtEmail.getText().toString();


            // Check if user filled the form
            if(name.trim().length() > 0 && email.trim().length() > 0){
                // Launch Main Activity
                Intent i = new Intent(getApplicationContext(), MainActivity.class);


                // Registering user on our server                   
                // Sending registraiton details to MainActivity
                i.putExtra("name", name);
                i.putExtra("email", email);
                session.registerEntry();

                SharedPreferences pref = getApplicationContext().getSharedPreferences("A4APrefs", 0); // 0 - for private mode
                Editor editor = pref.edit();

                Random r = new Random();
                int pairId = r.nextInt(999999-100000) + 100000;


                editor.putInt("conId", pairId); // Storing integer

                editor.commit(); // commit changes
                startActivity(i);
                finish();
            }else{
                // user doen't filled that data
                // ask him to fill the form
                alert.showAlertDialog(RegisterActivity.this, "Registration Error!", "Please enter your details", false);
            }
        }
    });
}

}

Why does this activity close after running itself once? I am really new to android and don't know much about it.

Error LogCat is as Follows.

06-19 23:26:03.007: E/GCMRegistrar(29350): internal error: retry receiver class not set yet
06-19 23:26:03.071: E/URL(29350): > http://some.com/gcm/register.php
06-19 23:26:04.049: E/AndroidRuntime(29350): FATAL EXCEPTION: IntentService[GCMIntentService-950252240713-2]
06-19 23:26:04.049: E/AndroidRuntime(29350): java.lang.NullPointerException
06-19 23:26:04.049: E/AndroidRuntime(29350):    at com.package.name.GCMIntentService.generateNotification(GCMIntentService.java:90)
06-19 23:26:04.049: E/AndroidRuntime(29350):    at com.package.name.GCMIntentService.onMessage(GCMIntentService.java:48)
06-19 23:26:04.049: E/AndroidRuntime(29350):    at com.google.android.gcm.GCMBaseIntentService.onHandleIntent(GCMBaseIntentService.java:223)
06-19 23:26:04.049: E/AndroidRuntime(29350):    at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:65)
06-19 23:26:04.049: E/AndroidRuntime(29350):    at android.os.Handler.dispatchMessage(Handler.java:99)
06-19 23:26:04.049: E/AndroidRuntime(29350):    at android.os.Looper.loop(Looper.java:154)
06-19 23:26:04.049: E/AndroidRuntime(29350):    at android.os.HandlerThread.run(HandlerThread.java:65)
06-19 23:26:05.056: E/UnRegister Receiver Error(29350): > Receiver not registered: com.google.android.gcm.GCMBroadcastReceiver@413d8ab8

And as per LogCat this line is GCMIntent is creating the error:

String[] separated = mmessage.split("::");
    String epurl = separated[2];
    String message = separated[1];
    String ntitle = separated[0];

I think the solution will be solved by converting these strings only if they contain the "::" in them, can you help me out?

Answer 1

If you're getting a NullPointerException on the line you specified, the only possible explanation is that mmessage is null.

If the problem was that the mmessage string didn't have enough "::" separators, the exception should have been ArrayIndexOutOfBoundsException and it would have been on one of the other lines.

The simple solution would be to check for mmessage being null and not execute that sequence of code if it is. However I expect the fact that it is null is a sign of a bigger problem elsewhere in your code.