Question

我的应用程序一直在崩溃onReceive基本上我发送gps坐标到另一个Android设备我试图在一段时间（真实）循环中从这些gps坐标集构建一个线方程，直到他将到达这一行，我使用while循环因为我需要等待，直到他会得到坐标来解决线的等式。

但它一直在崩溃。

那是我的OnReceive代码：

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;
        }
        }

那就是我的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

我猜它崩溃是因为while循环...需要你的帮助！

Answer 1

您的googleMap对象为空。

您只是声明了

GoogleMap googleMap;

但从未实例化。那么当你尝试做的时候，

googleMap.getMyLocation();

你遇到Null Pointer Exception。

Answer 2

它不是无限循环。它是第90行的NullPointerException。我在这里猜测：

 Location lm = googleMap.getMyLocation();

在尝试调用其中一种方法之前，请务必为googleMap指定一个值。

我的应用程序无法工作（无限循环}

2 个答案: