my app doesnt work ( infinite loop }

Question

My app keeps crashing onReceive Basically im sending gps coordinates to another android device and Im trying to build an equation of line from those sets of gps coordinates on a while(true) loop untill he will get to this line, Im using the while loop because I need to wait untill he will get coordinates to solve the equation of line.

But it keeps crashing .

thats my OnReceive code :

package com.example.yeah;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.google.android.gms.maps.GoogleMap;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.location.Location;
import android.os.Bundle;
import android.telephony.SmsMessage;
import android.widget.Toast;



    public class SmsListener extends BroadcastReceiver {


    GoogleMap googleMap; 


        public void onReceive(Context context, Intent intent) {

            Bundle bundle = intent.getExtras();

            Object messages[] = (Object[]) bundle.get("pdus");
            SmsMessage smsMessage[] = new SmsMessage[messages.length];
            for (int n = 0; n < messages.length; n++) {
                smsMessage[n] = SmsMessage.createFromPdu((byte[]) messages[n]);
            }

            //show first message
            Toast toast = Toast.makeText(context, "Received SMS: " +      smsMessage[0].getMessageBody(), Toast.LENGTH_LONG);
            toast.show();
            String s=smsMessage[0].getMessageBody();
            Matcher m = Pattern.compile("(?!=\\d\\.\\d\\.)([\\d.]+)").matcher(s);
            double[] d = new double[1000] ;
           int p=0;
            while (m.find())
            {
               double  k = Double.parseDouble(m.group(1));
               d[p]=k;
               p++;


            }


            int j,i=1,t,success=0;
            double line;
             double[] ship = new double[1000] ;
             double[] b = new double[1000] ;
             double lat;
             double lng;

             ship[0]=SlopeCalc(d[2],d[0],d[3],d[1]);
            b[0]=d[0]-ship[0]*d[1];


            if (p>3)
            {

            for(j=2;j<p;j++)
            {
                if(j+2<p){
                ship[i]=SlopeCalc(d[j+2],d[j-2+2],d[j+1+2],d[j-1+2]);
                b[i]=d[j]-(ship[i]*d[j+1]);
                j++;
                i++;
                }
                else{
                    break;
                }


            }

            }
            while(true)
            {
            Location lm = googleMap.getMyLocation();
            lat=lm.getLatitude();
            lng=lm.getLongitude();
            for (t=0;t<i;t++){
            line=ship[t]*lng+b[t]-lat;
            if (line==0){
                success=1;
                break;
            }
            }
            if (success==1){
            break;
            }

            }
            Toast poast = Toast.makeText(context, "I FOUND U", Toast.LENGTH_LONG);
            poast.show();
           abortBroadcast();

        }

        public static double SlopeCalc(double y2,double y1, double x2,double x1){

            double sou;
            sou=(y2-y1)/(x2-x1);
            return sou;
        }
        }

and thats my logcat :

05-09 21:44:24.165: E/Gsm/SmsMessage(2483): hasUserDataHeader : false
05-09 21:44:24.190: E/AndroidRuntime(2483): FATAL EXCEPTION: main
05-09 21:44:24.190: E/AndroidRuntime(2483): java.lang.RuntimeException: Unable to start receiver com.example.yeah.SmsListener: java.lang.NullPointerException
05-09 21:44:24.190: E/AndroidRuntime(2483):     at android.app.ActivityThread.handleReceiver(ActivityThread.java:1809)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at android.app.ActivityThread.access$2400(ActivityThread.java:117)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:985)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at android.os.Looper.loop(Looper.java:130)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at android.app.ActivityThread.main(ActivityThread.java:3691)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at java.lang.reflect.Method.invokeNative(Native Method)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at java.lang.reflect.Method.invoke(Method.java:507)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:665)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at dalvik.system.NativeStart.main(Native Method)
05-09 21:44:24.190: E/AndroidRuntime(2483): Caused by: java.lang.NullPointerException
05-09 21:44:24.190: E/AndroidRuntime(2483):     at com.example.yeah.SmsListener.onReceive(SmsListener.java:90)
05-09 21:44:24.190: E/AndroidRuntime(2483):     at android.app.ActivityThread.handleReceiver(ActivityThread.java:1798)
05-09 21:44:24.190: E/AndroidRuntime(2483):     ... 10 more

I guess its crashing because the while loop ... Need your help!

Because the stack trace indicates you have a null pointer exception at line 90. Do you know how to debug an app? — Andrew Fielden, May 10 '14 at 06:50
The problem is with the googlemap object as they said in the other answers ... i need to send the object from the mainactivity to the broadcast Receiver... Still trying to make it — mynavy, May 10 '14 at 07:04

score 2 · Accepted Answer · answered May 09 '14 at 19:00

2

Your googleMap object is null.

You have only declared it

GoogleMap googleMap;

but never instantiated. So then when you try to do,

googleMap.getMyLocation();

you run into Null Pointer Exception.

answered May 09 '14 at 19:00

Atul O Holic

6,692
4
39
74

Sorry buddy never used GoogleMaps yet. But this is what I found on Android Docs - You cannot instantiate a GoogleMap object directly, rather, you must obtain one from the getMap() method on a MapFragment or MapView that you have added to your application. – Atul O Holic May 09 '14 at 19:05
Yes it is declared in my MainActivity... it is working fine ther... im confused.. – mynavy May 09 '14 at 19:06
Oh ok, in that case please see this how to pass an object from Activity to your BroadcastReceiver - http://stackoverflow.com/questions/10032480/how-to-pass-data-to-broadcastreceiver – Atul O Holic May 09 '14 at 19:09
You will have to similarly pass your GoogleMap object here in order to access it. – Atul O Holic May 09 '14 at 19:10
I guess thats the problem .. but i dont understand what's in the registration the "com.myapp.myaction" is the name of the package or something? – mynavy May 09 '14 at 19:22
Thats a unique identifier basically a String which is used as an Action to identify your Broadcast Receiver. Kind of your own Intent-Filter. This is registered in the manifest file as – Atul O Holic May 09 '14 at 19:33

score 2 · Answer 2 · answered May 09 '14 at 19:02

2

It's not an infinite loop. It's a NullPointerException, at line 90. I'm guessing here:

 Location lm = googleMap.getMyLocation();

Make sure you assign a value to googleMap before you try to call one of its methods.

answered May 09 '14 at 19:02

ajpolt

1,002
6
10

I understand but what value should i assign if im assuming that the device is outside getting coordinates from the gps... ? – mynavy May 09 '14 at 19:03
From the Google documentation (assuming in your layout file you have a MapFragment with id "map": GoogleMap map = ((MapFragment) getFragmentManager() .findFragmentById(R.id.map)).getMap(); – ajpolt May 09 '14 at 19:08

my app doesnt work ( infinite loop }

2 Answers2

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