我的应用程序不工作(无限循环)

Question

我的应用程序一直崩溃onReceive基本上我发送gps坐标到另一个android设备，我试图从这些gps坐标集建立一个方程的线在一个while(true)循环，直到他将得到这条线，我使用while循环，因为我需要等待，直到他将得到坐标来解决方程的线

但是它总是死机。

这是我的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;
        }
        }

这是我的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。

你只是声明了它

GoogleMap googleMap;

，但从未实例化。所以当你尝试

googleMap.getMyLocation();

Answer 2

这不是一个无限循环。它是NullPointerException，在第90行。我猜在这里:

 Location lm = googleMap.getMyLocation();

请确保在您尝试调用它的一个方法之前为googleMap分配了一个值。