Android 显示标记 onClick 按钮

Question

我想绘制我得到的所有纬度和经度值的坐标。检查情节的第一个和最后一个，并使用不同的图标进行更改。在每个标记图上添加折线，在弹出窗口上添加可以隐藏/关闭的按钮。

我现在遇到的问题是，每当我删除按钮外的 for 循环时，都会出现空指针错误。

      @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        SupportMapFragment mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map1);
        mapFragment.getMapAsync(this);

        new GetVehicleValue().execute();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        // Inflate the layout for this fragment
        View v = inflater.inflate(R.layout.fragment_contact_us, container, false);
Button b = (Button) v.findViewById(R.id.button3);
        b.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

            }
        });

        if(vehicleHolder.size() != 0) {
        for(int i =0; i < vehicleHolder.size(); i++) {
            createMarker(i,vehicleHolder.get(i).getLatitude(),vehicleHolder.get(i).getLongitude(),vehicleHolder.get(i).getVehicle());
        }
    }

        return v;
    }

    public void createMarker(int index, String latitude, String longitude, String vehicle) {
        // Adding the taped point to the ArrayList
        BitmapDescriptor image = BitmapDescriptorFactory.fromResource(R.drawable.bus);
        Double lat = Double.parseDouble(latitude);
        Double Longitude = Double.parseDouble(longitude);
        float color = 0;

        mMap.addMarker(new MarkerOptions()
                .position(new LatLng(lat, Longitude))
                .anchor(0.5f, 0.5f)
                .title("title")
                .snippet("snippet"  )
                .icon(image));


    }

    class GetVehicleValue extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(getActivity());
            pDialog.setMessage("Please wait...");
            pDialog.setCancelable(false);
            pDialog.show();
        }

        @Override
        protected Void doInBackground(Void... arg0) {
            HttpHandler sh = new HttpHandler();

            // Making a request to url and getting response
            String jsonStr = sh.makeServiceCall(url);

            if (jsonStr != null) {
                try {
                    JSONArray jr = new JSONArray(jsonStr);

                    vehicleHolder = new ArrayList<>();
                    for (int i = 0; i < jsonStr.length(); i++) {
                        JSONObject jb = (JSONObject) jr.getJSONObject(i);
                        plate_num = jb.getString("plate_num");
                        gps_num = jb.getString("gps_num");
                        location = jb.getString("location");
                        date = jb.getString("date");
                        time = jb.getString("time");
                        lat = jb.getString("lat");
                        lng = jb.getString("lng");
                        engine = jb.getString("engine");
                        remarks = jb.getString("remarks");

                        vehicleHolder.add(new VehicleHolder(lat, lng));

                    }

                } catch (final JSONException e) {
                    e.printStackTrace();
                }
            } else {
                Log.d("JSON:", "is null");
            }

            return null;
        }

Answer 1

您的位置模型类：

public class LocationHolder {

    private String longitude,latitude,location,direction;

    public LocationHolder(String longitude, String latitude, String location, String direction) {
        this.longitude = longitude;
        this.latitude = latitude;
        this.location = location;
        this.direction = direction;
    }

    public String getLongitude() {
        return longitude;
    }

    public void setLongitude(String longitude) {
        this.longitude = longitude;
    }

    public String getLatitude() {
        return latitude;
    }

    public void setLatitude(String latitude) {
        this.latitude = latitude;
    }

    public String getLocation() {
        return location;
    }

    public void setLocation(String location) {
        this.location = location;
    }

    public String getDirection() {
        return direction;
    }

    public void setDirection(String direction) {
        this.direction = direction;
    }
}

解析：

public static ArrayList<LocationHolder>list_location=new ArrayList<>();
for (int i = 0; i < contacts.length(); i++) {
    JSONObject c = contacts.getJSONObject(i);
    String account = c.getString("account");
    String trxdate = c.getString("trxdate");
    String trxtime = c.getString("trxtime");
    String longitude = c.getString("long");
    String latitude = c.getString("lat");
    String location = c.getString("location");
    String direction = c.getString("direction");
    String compass = c.getString("compass");
    String id = c.getString("id");
    String remarks = c.getString("remarks");
    String status = c.getString("status");
    String kmrun = c.getString("kmrun");
    String speed = c.getString("speed");
    String totalkm = c.getString("totalkm");
    String engine = c.getString("engine");
    String plateno = c.getString("plateno");    

    list_location.add(new LocationHolder(longitude,latitude,location,direction,))
}

按钮点击

btn.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        for(int i=0;i<list_location.length();i++)
        {
            createMarker(list_location.get(i).getLatitude(),list_location.get(i).getLongitude(),list_location.get(i).getLocation());
        }
});

createMarker 函数：

private void createMarker(String latitude, String longitude,String snippet) {

    BitmapDescriptor icon = BitmapDescriptorFactory.fromResource(R.drawable.map_pin);
    Double lat = Double.parseDouble(latitude);
    Double Longitude = Double.parseDouble(longitude);

    googleMap.addMarker(new MarkerOptions()
            .position(new LatLng(lat, Longitude))
            .anchor(0.5f, 0.5f)
            .title(title)
            .snippet(snippet)
            .icon(icon));

    googleMap.setInfoWindowAdapter(new MarkerInfoWindowAdapter());

    googleMap.setOnInfoWindowClickListener(new GoogleMap.OnInfoWindowClickListener() {
        @Override
        public void onInfoWindowClick(Marker marker) {

            for (int i = 0; i < locationList.size(); i++) {
                  Log.d("TAG","getLatitude:"+list_location.get(i).getLatitude()+" getLongitude:"+list_location.get(i).getLongitude());
                if (marker.getSnippet().equals(list_location.get(i).getLocation())) {
                  Log.d("TAG","Selected Marker");
                }
            }
        }
    });
}

MarkerInfoWindowAdapter：添加您的自定义窗口信息 UI

  public class MarkerInfoWindowAdapter implements GoogleMap.InfoWindowAdapter {

    public MarkerInfoWindowAdapter() {
    }

    @Override
    public View getInfoWindow(Marker marker) {
        return null;
    }

    @Override
    public View getInfoContents(final Marker marker) {
       View v = getLayoutInflater().inflate(R.layout.custom_mapview, null);

        TextView markerLabel = (TextView) v.findViewById(R.id.tv_title);
        markerLabel.setText(marker.getTitle());

        return v;
    }
}

我的片段

GoogleMap googleMap;

class MyFragment extends Fragment implements OnMapReadyCallback {

    @Override
    public void onMapReady(GoogleMap map) {
        googleMap = map;
        setUpMap();
    }

    /*set up map*/
    private void setUpMap() {
        googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
        googleMap.setTrafficEnabled(true);
        googleMap.setIndoorEnabled(true);
        googleMap.setBuildingsEnabled(true);
        googleMap.getUiSettings().setZoomControlsEnabled(true);
        CameraPosition cameraPosition = new CameraPosition.Builder().target(new LatLng(0.0, 0.0)).zoom(15).build();
        googleMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));

        //set marker here
    }
}

尝试将列表存储到数组列表中，

dependencies {
    compile 'com.google.code.gson:gson:2.2.+'
}       

设置值

    SharedPreferences preferences = getSharedPreferences("AppPrefs", MODE_PRIVATE);
    SharedPreferences.Editor PrefsEditor = preferences.edit();


Gson gson = new Gson();

String jsonText = gson.toJson(list_location );
prefsEditor.putString("key", jsonText);
prefsEditor.commit();

检索值

List<LocationHolder> addArray  = new ArrayList<>();
Gson gson = new Gson();
String jsonText = Prefs.getString("key", null);
String[] text = gson.fromJson(jsonText, String[].class);

addArray = Arrays.asList(text);
addArray = new ArrayList(addArray);

Answer 2

将location 和direction 设为字段

String lattitude;
String longitude;

然后在doInBackground改代码为

lattitude = c.getString("lattitude");
longitude= c.getString("longitude");

那么它们可以用于onClick