java.lang.NullPointerException: Versuch, die virtuelle Methode 'java.lang.String java.lang.String.trim()' für eine Nullobjekt-Referenz aufzurufen

Question

Ich muss eine Aufgabe lösen, in der ich den spezifischen Ort anzeigen muss Alle Breitengrade aus der Datenbank, deren Entfernung nicht mehr als 100 Meter von meinem aktuellen Standort entfernt ist.

Hier ist meine Haupttätigkeit:

@Override 
    protected void onCreate(final Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     MultiDex.install(this); 
     setContentView(R.layout.activity_maps); 


     //etOrigin = (EditText) findViewById(R.id.etOrigin); 

     btnFindPath = (Button) findViewById(R.id.btnFindPath); 

     SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager() 
       .findFragmentById(R.id.map); 
     mapFragment.getMapAsync(this); 

     DatabaseHandler db = new DatabaseHandler(getApplicationContext()); 
     // Inserting Contacts 
     Log.d("Insert: ", "Inserting .."); 
     // db.addLocation(new LocationManager(1,); 
     db.addLocation(new LocationManager(1, "23.780551", "90.416380", "Gulshan-1")); 
     db.addLocation(new LocationManager(2, "23.780315", "90.418354", "Gulshan-1")); 
     db.addLocation(new LocationManager(3, "23.780472", "90.415093", "Gulshan-1")); 
     db.addLocation(new LocationManager(4, "23.780786", "90.422817", "Gulshan-1")); 

     db.addLocation(new LocationManager(5, "23.776734", "90.425558", "Badda")); 
     db.addLocation(new LocationManager(6, "23.776538", "90.425601", "Badda")); 
     db.addLocation(new LocationManager(7, "23.776572", "90.425563", "Badda")); 
     db.addLocation(new LocationManager(8, "23.776911", "90.425595", "Badda")); 

     db.addLocation(new LocationManager(9, "23.781436", "90.425442", "Pran RFl")); 
     db.addLocation(new LocationManager(10, "23.781293", "90.425583", "Pran RFl")); 
     db.addLocation(new LocationManager(11, "23.781307", "90.425280", "Pran RFl")); 
     db.addLocation(new LocationManager(12, "23.781481", "90.425591", "Pran RFl")); 

     btnFindPath.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 

       mMap.clear(); 
       sendRequest(); 
      } 
     }); 

    } 

    @Override 
    public void onPause() { 
     super.onPause(); 


     if (mGoogleApiClient != null) { 
      LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this); 
     } 
    } 

    @Override 
    public void onMapReady(GoogleMap googleMap) { 
     mMap = googleMap; 

     if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) { 
      if (ContextCompat.checkSelfPermission(this, 
        Manifest.permission.ACCESS_FINE_LOCATION) 
        == PackageManager.PERMISSION_GRANTED) { 

       buildGoogleApiClient(); 
       mMap.setMyLocationEnabled(true); 
      } else { 

       checkLocationPermission(); 
      } 
     } 
     else { 
      buildGoogleApiClient(); 
      mMap.setMyLocationEnabled(true); 
     } 
    } 

    protected synchronized void buildGoogleApiClient() { 
     mGoogleApiClient = new GoogleApiClient.Builder(this) 
       .addConnectionCallbacks(this) 
       .addOnConnectionFailedListener(this) 
       .addApi(LocationServices.API) 
       .build(); 
     mGoogleApiClient.connect(); 




     if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { 
      // TODO: Consider calling 
      // ActivityCompat#requestPermissions 
      // here to request the missing permissions, and then overriding 
      // public void onRequestPermissionsResult(int requestCode, String[] permissions, 
      //           int[] grantResults) 
      // to handle the case where the user grants the permission. See the documentation 
      // for ActivityCompat#requestPermissions for more details. 
      return; 
     } 
     /* mMap.setMyLocationEnabled(true);*/ 


    } 

@Override 
    public void onConnected(Bundle bundle) { 
     mLocationRequest = new LocationRequest(); 
     mLocationRequest.setInterval(1000); 
     mLocationRequest.setFastestInterval(1000); 
     mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY); 
     if (ContextCompat.checkSelfPermission(this, 
       Manifest.permission.ACCESS_FINE_LOCATION) 
       == PackageManager.PERMISSION_GRANTED) { 
      LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this); 
     } 
    } 

    @Override 
    public void onConnectionSuspended(int i) {} 

    @Override 
    public void onConnectionFailed(ConnectionResult connectionResult) {} 

    @Override 
    public void onLocationChanged(Location location) 
    { 
     mLastLocation = location; 
     if (mCurrLocationMarker != null) { 
      mCurrLocationMarker.remove(); 
     } 

     //Place current location marker 
     latitude = location.getLatitude(); 
     longitude = location.getLongitude(); 
     // to get current location without click event code has to be added here 
     if (mGoogleApiClient != null) { 
      LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this); 
     } 
    } 

    public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99; 
    private void checkLocationPermission() { 
     if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) 
       != PackageManager.PERMISSION_GRANTED) { 

      if (ActivityCompat.shouldShowRequestPermissionRationale(this, 
        Manifest.permission.ACCESS_FINE_LOCATION)) { 

       new AlertDialog.Builder(this) 
         .setTitle("Location Permission Needed") 
         .setMessage("This app needs the Location permission, please accept to use location functionality") 
         .setPositiveButton("OK", new DialogInterface.OnClickListener() { 
          @Override 
          public void onClick(DialogInterface dialogInterface, int i) { 
           //Prompt the user once explanation has been shown 
           ActivityCompat.requestPermissions(MapsActivity.this, 
             new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 
             MY_PERMISSIONS_REQUEST_LOCATION); 
          } 
         }) 
         .create() 
         .show(); 


      } else { 
       // No explanation needed, we can request the permission. 
       ActivityCompat.requestPermissions(this, 
         new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 
         MY_PERMISSIONS_REQUEST_LOCATION); 
      } 
     } 
    } 

    @Override 
    public void onRequestPermissionsResult(int requestCode, 
              String permissions[], int[] grantResults) { 
     switch (requestCode) { 
      case MY_PERMISSIONS_REQUEST_LOCATION: { 

       if (grantResults.length > 0 
         && grantResults[0] == PackageManager.PERMISSION_GRANTED) { 

        if (ContextCompat.checkSelfPermission(this, 
          Manifest.permission.ACCESS_FINE_LOCATION) 
          == PackageManager.PERMISSION_GRANTED) { 

         if (mGoogleApiClient == null) { 
          buildGoogleApiClient(); 
         } 
         mMap.setMyLocationEnabled(true); 
        } 

       } else { 

        Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show(); 
       } 
       return; 
      } 


     } 
    } 

    private double findDistance(double lat1, double lon1, double lat2, double lon2) { 
     double theta = lon1 - lon2; 
     double dist = Math.sin(deg2rad(lat1)) * Math.sin(deg2rad(lat2)) + Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) * Math.cos(deg2rad(theta)); 
     dist = Math.acos(dist); 
     dist = rad2deg(dist); 
     dist = dist * 60 * 1.1515; 
     return (dist); 
    } 

    private double deg2rad(double deg) { 
     return (deg * Math.PI/180.0); 
    } 

    private double rad2deg(double rad) { 
     return (rad * 180.0/Math.PI); 
    } 





    private void sendRequest() { 

     LatLng latLng = new LatLng(latitude,longitude); 
     MarkerOptions markerOptions = new MarkerOptions(); 
     markerOptions.position(latLng); 
     markerOptions.title("Current Position"); 
     markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA)); 
     mCurrLocationMarker = mMap.addMarker(markerOptions); 


     CircleOptions addCircle = new CircleOptions().center(latLng).radius(radiusInMeters).fillColor(shadeColor).strokeColor(strokeColor).strokeWidth(8); 
     mCircle = mMap.addCircle(addCircle); 

     mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng)); 
     mMap.animateCamera(CameraUpdateFactory.zoomTo(11)); 

     DatabaseHandler db = new DatabaseHandler(getApplicationContext()); 
     List<LocationManager> locations = db.getAllLocations(); 

     for (LocationManager cn : locations) { 

      finlat1 = Double.valueOf(cn.getLatitude()); 
      finlon2 = Double.valueOf(cn.getLongitude()); 
      String name = cn.getPlacename(); 
      double distance = findDistance(latitude, longitude, finlat2, finlon2) * 1000; 

      if (distance <= 100.00) { 

       LatLng venus = new LatLng(finlat2, finlon2); 
       Log.wtf("venus:", String.valueOf(venus)); 
       mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(venus, 18)); 
       originMarkers.add(mMap.addMarker(new MarkerOptions() 
         .icon(BitmapDescriptorFactory.fromResource(R.drawable.mark)) 
         .title(name) 
         .position(venus))); 
      } 

     } 




     return; 

    } 



} 

Mein db-Handler ist: DatabaseHandler.java

package com.pran.vehicletrackingapp.dbhelper; 

/** 
* Created by Administrator on 11/30/2016. 
*/ 
import java.util.ArrayList; 
import java.util.List; 

import android.content.ContentValues; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 

import static java.lang.Integer.*; 

public class DatabaseHandler extends SQLiteOpenHelper { 
    private static final int DATABASE_VERSION = 1; 
    private static final String DATABASE_NAME = "locationStore"; 
    private static final String TABLE_LOCATION = "locations"; 
    private static final String KEY_ID = "id"; 
    private static final String KEY_LATITUDE = "latitude"; 
    private static final String KEY_LONGITUDE = "longitude"; 
    private static final String KEY_PLACENAME = "placename"; 

    // private static final String KEY_PH_NO = "phone_number"; 

    public DatabaseHandler(Context context) { 
     super(context, DATABASE_NAME, null, DATABASE_VERSION); 
     //3rd argument to be passed is CursorFactory instance 
    } 



    // Creating Tables 
    @Override 
    public void onCreate(SQLiteDatabase db) { 
     String CREATE_LOCATION_TABLE = "CREATE TABLE " + TABLE_LOCATION + "(" 
       + KEY_ID + " ID INTEGER PRIMARY KEY AUTOINCREMENT ," 
       + KEY_LATITUDE + " TEXT ," 
       + KEY_LONGITUDE + " TEXT ," 
       + KEY_PLACENAME + " TEXT," 
       + ")"; 
     db.execSQL(CREATE_LOCATION_TABLE); 
    } 

    // Upgrading database 
    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
     // Drop older table if existed 
     db.execSQL("DROP TABLE IF EXISTS " + TABLE_LOCATION); 

     // Create tables again 
     onCreate(db); 
    } 

    // code to add the new contact 
    public void addLocation(LocationManager location) { 
     SQLiteDatabase db = this.getWritableDatabase(); 

     ContentValues values = new ContentValues(); 
     values.put(KEY_ID , location.getID()); 
     values.put(KEY_LATITUDE, location.getLatitude()); 
     values.put(KEY_LONGITUDE , location.getLongitude()); 
     values.put(KEY_PLACENAME, location.getPlacename()); // Contact Name 
     //values.put(KEY_PH_NO, location.getPhoneNumber()); // Contact Phone 

     // Inserting Row 
     db.insert(TABLE_LOCATION, null, values); 
     //2nd argument is String containing nullColumnHack 
     db.close(); // Closing database connection 
    } 

    // code to get the single contact 
    LocationManager getLocation(int id) { 
     SQLiteDatabase db = this.getReadableDatabase(); 

     Cursor cursor = db.query(TABLE_LOCATION, new String[] { 
       KEY_ID,KEY_LONGITUDE,KEY_LONGITUDE,KEY_PLACENAME}, KEY_ID + "=?", 
       new String[] { String.valueOf(id) }, null, null, null, null); 
     if (cursor != null) 
      cursor.moveToFirst(); 

     LocationManager location = new LocationManager(cursor.getInt(0),cursor.getString(1),cursor.getString(2),cursor.getString(3)); 
     // return contact 
     return location; 
    } 

    // code to get all contacts in a list view 
    public List<LocationManager> getAllLocations() { 
     List<LocationManager> contactList = new ArrayList<LocationManager>(); 
     // Select All Query 
     String selectQuery = "SELECT * FROM " + TABLE_LOCATION; 

     SQLiteDatabase db = this.getWritableDatabase(); 
     Cursor cursor = db.rawQuery(selectQuery, null); 

     // looping through all rows and adding to list 


     if (cursor.moveToFirst()) { 
      do { 
       LocationManager location = new LocationManager(); 
       location.setID(cursor.getInt(0)); 
       location.setLatitude(cursor.getString(1)); 
       location.setLongitude(cursor.getString(2)); 
       location.setPlacename(cursor.getString(3)); 
       // contact.setPhoneNumber(cursor.getString(2)); 
       // Adding contact to list 
       contactList.add(location); 
      } while (cursor.moveToNext()); 
     } 

     // return contact list 
     return contactList; 
    } 

    // code to update the single contact 
    public int updateLocation(LocationManager location) { 
     SQLiteDatabase db = this.getWritableDatabase(); 

     ContentValues values = new ContentValues(); 
     values.put(KEY_ID , location.getID()); 
     values.put(KEY_LATITUDE, location.getLatitude()); 
     values.put(KEY_LONGITUDE , location.getLongitude()); 
     values.put(KEY_PLACENAME, location.getPlacename()); 

     // updating row 
     return db.update(TABLE_LOCATION, values, KEY_ID + " = ?", 
       new String[] { String.valueOf(location.getID()) }); 
    } 

    // Deleting single contact 
    public void deleteLocation(LocationManager location) { 
     SQLiteDatabase db = this.getWritableDatabase(); 
     db.delete(TABLE_LOCATION, KEY_ID + " = ?", 
       new String[] { String.valueOf(location.getID()) }); 
     db.close(); 
    } 

    // Getting contacts Count 
    public int getLocationCount() { 
     String countQuery = "SELECT * FROM " + TABLE_LOCATION; 
     SQLiteDatabase db = this.getReadableDatabase(); 
     Cursor cursor = db.rawQuery(countQuery, null); 
     cursor.close(); 

     // return count 
     return cursor.getCount(); 
    } 

} 

Aber es hat den Fehler angezeigt:

FATAL EXCEPTION: main Process: com.pran.vehicletrackingapp, PID: 16019 java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.String.trim()' on a null object reference at java.lang.StringToReal.parseDouble(StringToReal.java:263) at java.lang.Double.parseDouble(Double.java:301) at java.lang.Double.valueOf(Double.java:338) at com.pran.vehicletrackingapp.MapsActivity.sendRequest(MapsActivity.java:323) at com.pran.vehicletrackingapp.MapsActivity.access$100(MapsActivity.java:46) at com.pran.vehicletrackingapp.MapsActivity$1.onClick(MapsActivity.java:118) at android.view.View.performClick(View.java:5716) at android.widget.TextView.performClick(TextView.java:10926) at android.view.View$PerformClick.run(View.java:22596) at android.os.Handler.handleCallback(Handler.java:739) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:148) at android.app.ActivityThread.main(ActivityThread.java:7325) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

Wie kann ich lösen es?

Answer 1

Die Linie

+ KEY_ID + " ID INTEGER PRIMARY KEY AUTOINCREMENT ," 

sollte

seine

+ KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT ,"