从片段到片段发送双类型数据，显示空指针异常

Question

我有MapActivity＆amp; LocationSendActivity从片段扩展而来。 将MapActivity中的双类型数据传递给LocationSendActivity时，它会在MapActivity中显示错误“java.lang.NullPointerException”.Data

 LocationSendActivity frag=new LocationSendActivity();
        Bundle bnd1=new Bundle();
        bnd1.putDouble("lat", latitude);
        bnd1.putDouble("lng", longitude);
        frag.setArguments(bnd1);

LocationActivity中的数据是

Bundle bnd=this.getArguments();
        latt=bnd.getDouble("lat");
        lngt=bnd.getDouble("lng")

MapActivity ..........

package com.example.map;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

import android.content.Context;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationManager;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.util.Log;
import android.view.InflateException;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class MapActivity extends Fragment {
    private GoogleMap gmap;
    public SupportMapFragment smf;
    public double latitude,longitude;
    public static View view;
    private FragmentManager fm;
    public boolean wifi,gps,network,val;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        if (view != null) {
            ViewGroup parent = (ViewGroup) view.getParent();
            if (parent != null)
                parent.removeView(view);
         }
        try{
        view = inflater.inflate(R.layout.map, container, false);

        try{
            initializemap();
            gmap.setMyLocationEnabled(true);
            gmap.getUiSettings().setZoomControlsEnabled(true);
            gmap.getUiSettings().setMyLocationButtonEnabled(true);

            // Get LocationManager object from System Service LOCATION_SERVICE
            LocationManager locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);

            // Create a criteria object to retrieve provider
            Criteria criteria = new Criteria();

            // Get the name of the best provider
            String provider = locationManager.getBestProvider(criteria, true);

            // Get Current Location
            Location myLocation = locationManager.getLastKnownLocation(provider);

            //set map type
            //gmap.setMapType(GoogleMap.MAP_TYPE_HYBRID);

            // Get latitude of the current location
            latitude = myLocation.getLatitude();

            // Get longitude of the current location
            longitude = myLocation.getLongitude();

            // Create a LatLng object for the current location
            LatLng latLng = new LatLng(latitude, longitude);      

            // Show the current location in Google Map        
            gmap.moveCamera(CameraUpdateFactory.newLatLng(latLng));

            // Enable / Disable Compass icon
            gmap.getUiSettings().setCompassEnabled(true);

            // Enable / Disable Rotate gesture
            gmap.getUiSettings().setRotateGesturesEnabled(true);

            //Set zooming control on goole to view location
            gmap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 15));

           //Add marker at current position
             MarkerOptions marker=new MarkerOptions();
             marker.icon(BitmapDescriptorFactory.fromResource(R.drawable.arr));
           //marker.position(latLng).anchor(1,1).rotation(90);
             gmap.addMarker(marker.position(new LatLng(latitude, longitude)).title("You are here!"));
           //Remove default marker
           //gmap.clear();  
            }catch(Exception e){
                 e.printStackTrace();
            }
        }catch (InflateException e) {
            // TODO: handle exception
        }
        //Dialog call
        showDialog();
        Log.e("latlng", Double.toString(latitude));
        //Set data for LocationSendActivity
        LocationSendActivity frag=new LocationSendActivity();
        Bundle bnd1=new Bundle();
        bnd1.putDouble("lat", latitude);
        bnd1.putDouble("lng", longitude);
        frag.setArguments(bnd1);

        return view;
    }

    public void showDialog() {
        //Check network
         LocationManager lm = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
         try{
             network = lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
            }catch(Exception ex){}
        //Check Wifi
         WifiManager wfm =(WifiManager)getActivity().getSystemService(Context.WIFI_SERVICE);
         wifi = wfm.isWifiEnabled();
        //Check Gps
        try{
            gps = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
            }catch(Exception ex){}

        //call dialog class
        val=network && wifi && gps;
        if(!val){
            DialogFragment dial =new  AlertDialogFragment();
            Bundle bnd=new Bundle();
            bnd.putBoolean("net", network);
            bnd.putBoolean("wi", wifi);
            bnd.putBoolean("gps",gps);
            dial.setArguments(bnd); 
            dial.show(getFragmentManager(),"dialogShow");   
        }                                 
    }

    public void onResume(){
        super.onResume();
        initializemap();
    } 

    private void initializemap() {
        // TODO Auto-generated method stub
        if(gmap == null){
            fm=getFragmentManager();
            Fragment ft=fm.findFragmentById(R.id.map);
            smf=(SupportMapFragment)ft;
            gmap=smf.getMap();  

        } 
    } 

}



LocationSendActivity...........
   package com.example.map;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class LocationSendActivity extends Fragment {

    private double latt,lngt;
    private TextView tv1,tv2;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Bundle bnd=this.getArguments();
        latt=bnd.getDouble("lat");
        lngt=bnd.getDouble("lng");  
    }

    public View onCreateView(LayoutInflater inflater,ViewGroup container,
            Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        View v=inflater.inflate(R.layout.locationsend, container, false);
    /*  tv1=(TextView)v.findViewById(R.id.textView3);
        tv1.setText(String.valueOf(latt));
        tv2=(TextView)v.findViewById(R.id.textView4);
        tv2.setText(String.valueOf(lngt));  */

        return v;
    }

}

的logcat ........

11-30 12:46:34.238: W/System.err(5880): java.io.IOException: Permission denied
11-30 12:46:34.248: E/AndroidRuntime(5880): FATAL EXCEPTION: main
11-30 12:46:34.248: E/AndroidRuntime(5880): java.lang.NullPointerException
11-30 12:46:34.248: E/AndroidRuntime(5880):     at com.example.map.LocationSendActivity.onCreate(LocationSendActivity.java:18)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at android.support.v4.app.Fragment.performCreate(Fragment.java:1455)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:893)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1460)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at android.os.Handler.handleCallback(Handler.java:587)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at android.os.Handler.dispatchMessage(Handler.java:92)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at android.os.Looper.loop(Looper.java:123)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at android.app.ActivityThread.main(ActivityThread.java:4635)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at java.lang.reflect.Method.invokeNative(Native Method)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at java.lang.reflect.Method.invoke(Method.java:521)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:916)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:674)
11-30 12:46:34.248: E/AndroidRuntime(5880):     at dalvik.system.NativeStart.main(Native Method)
11-30 12:46:34.258: I/global(5880): Default buffer size used in BufferedWriter constructor. It would be better to be explicit if an 8k-char buffer is required.