Question

我有一张名为MapActivity的地图 activity.MapActivity从第一次加载fragment.Map延伸成功。当我从活动中寻找其他片段。之后这个当我按下地图按钮时，地图显示为空白 screen.Any idea？

MapActivity

 package com.example.map;

import updatedata.FindMapDataService;

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

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.InflateException;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

public  class MapActivity extends Fragment implements OnMyLocationChangeListener  {
    public  GoogleMap gmap;
    public static double maillat,maillng,latitude,longitude,elat5,elng5;
    public static String flat5,flng5;
    public static int s,state,check;
    public static long utime,ftime;
    View view;
    public static Runnable runn;
    public static Handler handler;
    public boolean wifi,gps,network,val,inter;


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

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
        // location data find from MainActivitiy
            elat5=MainActivity.lat10;
            elng5=MainActivity.lng10;
        // location data find from LocationFindactivity 
             flat5=LocationFindActivity.latt;
             flng5=LocationFindActivity.lng;
        // find status for opening map
             s=MainActivity.status;
        // find time for handler
             if(ftime == 0){
                    ftime=15000;
                }
        // Load Preferences
             LoadPreferences();
        //get view  
         if (view != null) {
                ViewGroup parent = (ViewGroup) view.getParent();
                if (parent != null)
                    parent.removeView(view);
             }  
         try{
            view = inflater.inflate(R.layout.map, container, false);
         }catch(InflateException e){
            e.printStackTrace();
         }
        //Check location data source
        if(s==1){
            initializemailmap();
            check=1;
            Log.e("Activity","link");
        }else if(s==2){
            elat5=Double.parseDouble(flat5);
            elng5=Double.parseDouble(flng5);
            check=1;
            initializemailmap();
            Log.e("Activity","Find");
        }else{
             initializemap();
            check=0;
            Log.e("Activity","Normal");
        }


        if( check == 1){
                getActivity().startService(new Intent(getActivity(),FindMapDataService.class));
                handler = new Handler();
                handler.postDelayed(runn, 10000);
            }

        runn = new Runnable() {
               @Override
               public void run() {
                   flat5=FindMapDataService.latt;
                   flng5=FindMapDataService.lng;
                   if(flat5 != null  && flng5 != null){
                        elat5=Double.parseDouble(flat5);
                        elng5=Double.parseDouble(flng5);
                        createMailMap();
                    } 
                   // createMailMap();
                   handler.postDelayed(this, ftime);
               }
        };

        // Show current location    
            gmap.setMyLocationEnabled(true);
            if(check == 0){
                LocationManager locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
                Criteria criteria = new Criteria();
                criteria.setAccuracy(Criteria.ACCURACY_FINE);
                String provider = locationManager.getBestProvider(criteria, true);
                Location location = locationManager.getLastKnownLocation(provider); 
                double glat = location.getLatitude();
                double glng = location.getLongitude();
                CameraUpdate myLoc = CameraUpdateFactory.newCameraPosition(
                  new CameraPosition.Builder().target(new LatLng(glat,glng)).zoom(12).build());
                gmap.moveCamera(myLoc); 

            }


        return view;
    }

    public void onMyLocationChange(Location arg0) {
        // TODO Auto-generated method stub
        double lat=arg0.getLatitude();
        double lng=arg0.getLongitude();
        CameraUpdate myLoc = CameraUpdateFactory.newCameraPosition(
                new CameraPosition.Builder().target(new LatLng(lat,lng)).zoom(15).build());
        gmap.moveCamera(myLoc);
        gmap.setOnMyLocationChangeListener(null);

    }


    //after mail initialisation
    private void initializemailmap() {
        // TODO Auto-generated method stub
        if(gmap == null){
            Fragment ft=getFragmentManager().findFragmentById(R.id.mymap);
            gmap=((SupportMapFragment) ft).getMap();
            createMailMap();
        }  else{
            createMailMap();
            Log.e("Find","Create Mail Map");
        } 
    }


    //Normal initialisation
    private void initializemap() {
        // TODO Auto-generated method stub
        if(gmap == null){   
            Fragment ft1=getFragmentManager().findFragmentById(R.id.mymap);
            gmap=((SupportMapFragment) ft1).getMap(); 
        } 
        if (gmap == null) {
            Toast.makeText(getActivity(),
                    "Sorry! unable to create maps", Toast.LENGTH_SHORT)
                    .show();
        }   
    }  

    private void createMailMap() {
        // TODO Auto-generated method stub
            maillat=elat5;
          // Log.e("latBrowser", Double.toString(latitude));
            maillng=elng5;

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

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

          //Set zooming control on goole to view location
             gmap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 12));

          //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(maillat, maillng)).title("You are here!"));
          //Remove default marker
             // gmap.clear();           
    }

    //save preferences
    private  void SavePreferences(){
        SharedPreferences sharedPreferences = getActivity().getPreferences(Context.MODE_PRIVATE );
        SharedPreferences.Editor editor = sharedPreferences.edit();
        // editor.putInt("val", state);
        editor.putLong("time", utime);
        editor.commit();  
    }
    //load preferences
    private void LoadPreferences(){
        SharedPreferences sharedPreferences = getActivity().getPreferences(Context.MODE_PRIVATE);
        // mapstatus = sharedPreferences.getInt("val",1);
        ftime=sharedPreferences.getLong("time", 1);
       }

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

    public void onStop(){
        super.onStop();
        SavePreferences();
        gmap = null;
    } 

    public void onDestroyView() {
        super.onDestroyView();
        Fragment f = (SupportMapFragment) getFragmentManager().findFragmentById(R.id.mymap);
        if (f != null){ 
            getFragmentManager().beginTransaction().remove(f).commitAllowingStateLoss();
        } 
    } 

    public void onDestroy(){
        super.onDestroy();
        MainActivity.status=0;
        if(check == 1){
         getActivity().stopService(new Intent(getActivity(),FindMapDataService.class));
        }
        SavePreferences();
    }


}

Answer 1

在Fragment

中使用地图时需要销毁地图

public void onDestroy(){
        gmap = null;
        super.onDestroy();
        MainActivity.status=0;
        if(check == 1){
         getActivity().stopService(new Intent(getActivity(),FindMapDataService.class));
        }
        SavePreferences();


    }

也在OnCreateView方法中更新

    ...
         //Check location data source
 initializemailmap();            
if(s==1){

                check=1;
                Log.e("Activity","link");
            }else if(s==2){
                elat5=Double.parseDouble(flat5);
                elng5=Double.parseDouble(flng5);
                check=1;
                initializemailmap();
                Log.e("Activity","Find");
            }else{
                 initializemap();
                check=0;
                Log.e("Activity","Normal");
            }
    ...

来自OnCreateView menthod的代码

我希望它有所帮助。

Answer 2

在我的情况下，我使用getFragmentManager().beginTransaction()更改了getChildFragmentManager().beginTransaction()，现在一切正常。

后面按了谷歌地图api v2后的空白屏幕

2 个答案: