如何使用 lon/lat 在 arraylist 中绘制地图？

Posted 2023-04-14

【中文标题】如何使用 lon/lat 在 arraylist 中绘制地图？

【英文标题】：How to plot on maps from arraylist with lon/lat?

【发布时间】：2013-11-13 02:18:13

【问题描述】：

这是我的地图类...

public class Mapa extends FragmentActivity implements LocationListener    

public GoogleMap map;

@Override
protected void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_mapa);

获取 Google Play 可用性状态

    int status =GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext());

显示状态 if(status!=ConnectionResult.SUCCESS) // Google Play 服务不可用

        int requestCode = 10;
        Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode);
        dialog.show();

    else  

获取对 SupportMapFragment 的引用

        SupportMapFragment fm = (SupportMapFragment) 
        getSupportFragmentManager().findFragmentById(R.id.map);

从片段中获取 GoogleMap 对象

        map = fm.getMap();

启用 Google 地图的 MyLocation 图层

        map.setMyLocationEnabled(true);

从系统服务 LOCATION_SERVICE 获取 LocationManager 对象

        LocationManager locationManager = (LocationManager) 

    getSystemService(LOCATION_SERVICE);

创建一个标准对象来检索提供者

        Criteria criteria = new Criteria();

获取最佳提供商的名称

        String provider = locationManager.getBestProvider(criteria, true);

获取当前位置

        Location location = locationManager.getLastKnownLocation(provider);

        if(location!=null)
            onLocationChanged(location);
        
        locationManager.requestLocationUpdates(provider, 20000, 0, this);



    


public void onLocationChanged(Location location) 

    TextView tvLocation = (TextView) findViewById(R.id.tv_location);

获取当前位置的纬度

    double latitude = location.getLatitude();

获取当前位置的经度

    double longitude = location.getLongitude();

为当前位置创建一个 LatLng 对象

    LatLng latLng = new LatLng(latitude, longitude);

在谷歌地图中显示当前位置

    map.moveCamera(CameraUpdateFactory.newLatLng(latLng));

放大 Google 地图

    map.animateCamera(CameraUpdateFactory.zoomTo(15));

在 TextView tv_location 中设置经纬度

    tvLocation.setText("Latitude:" +  latitude  + ", Longitude:"+ longitude );



@Override
public void onProviderDisabled(String provider) 



@Override
public void onProviderEnabled(String provider) 
       

@Override
public void onStatusChanged(String provider, int status, Bundle extras) 

这是我的数组列表类

  public void getPontos(View view) 

    String codigo;

    codigo = linhaList.get(spinner.getSelectedItemPosition()).getCodigo();

    new WebServiceGetPontosLinha().execute(codigo);



private class WebServiceGetPontosLinha extends
        AsyncTask<String, Void, Void> 

    @Override
    protected void onPreExecute() 

        progressDialog = ProgressDialog.show(MainActivity.this, "",
                getResources().getText(R.string.connecting), true, false);
    

    @Override
    protected Void doInBackground(String... params) 

        WebServiceConsumer webServiceConsumer = new WebServiceConsumer(
                MainActivity.this);

        pontoList = webServiceConsumer.getPontos(params[0]);

        return null;
    

    @Override
    protected void onPostExecute(Void result) 

        progressDialog.dismiss();

        pontoArrayAdapter = new ArrayAdapter<PontosLinhas>(
                MainActivity.this,
                android.R.layout.simple_spinner_dropdown_item, pontoList);
        spinner1.setAdapter(pontoArrayAdapter);
    

如何像图像一样在地图上绘制微调器的内容？

【问题讨论】：

那么，您有一个包含纬度/经度的数组，您想将其添加为地图上的标记？否则不确定我是否理解了这个问题。

【参考方案1】：

这涉及到很多你不需要的细节，但希望你能明白。

我开发了一个应用程序，它可以在地图上显示消火栓的位置，这就是我将消火栓加载到地图上的方式：

    private class LoadHydrantsToMapTask extends
        AsyncTask<Hydrant, Integer, List<MarkerOptions>> 

    private int loadHydrantsGoal = 0;

    public LoadHydrantsToMapTask(int loadHydrantsGoal) 
        this.loadHydrantsGoal = loadHydrantsGoal;
    

    // Before running code in separate thread
    @Override
    protected void onPreExecute() 
        Device.lockOrientation((Activity)context);
        // Create a new progress dialog.
        progressDialog = new ProgressDialog(context);
        // Set the progress dialog to display a horizontal bar .
        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        progressDialog.setMessage(context
                .getString(R.string.adding_hydrants));
        // This dialog can't be canceled by pressing the back key.
        progressDialog.setCancelable(false);
        // This dialog isn't indeterminate.
        progressDialog.setIndeterminate(false);
        // The maximum number of progress items is 100.
        progressDialog.setMax(loadHydrantsGoal);
        // Set the current progress to zero.
        progressDialog.setProgress(0);
        // Display the progress dialog.
        progressDialog.show();

    

    // The code to be executed in a background thread.
    @Override
    protected List<MarkerOptions> doInBackground(Hydrant... hydrants) 
        List<MarkerOptions> markers = new ArrayList<MarkerOptions>();

        for (Hydrant hydrant : hydrants) 

            final String hydrant_type = hydrant.getHydrantType();
            final String hydrant_icon_path = hydrant.getIconPath();
            double latitude = hydrant.getLatitude();
            double longitude = hydrant.getLongitude();

            final LatLng position = new LatLng(latitude, longitude);

            final String address = hydrant.getAddress();
            final String addressNumber = hydrant.getAddressNumber();
            final String addres-s-remark = hydrant.getAddressRemark();
            final String remark = hydrant.getRemark();


            BitmapDescriptor icon = BitmapDescriptorFactory
                    .defaultMarker(BitmapDescriptorFactory.HUE_RED);

            if (!hydrant_icon_path.isEmpty()) 
                File iconfile = new File(hydrant_icon_path);
                if (iconfile.exists()) 
                    BitmapDescriptor loaded_icon = BitmapDescriptorFactory
                            .fromPath(hydrant_icon_path);
                    if (loaded_icon != null) 
                        icon = loaded_icon;
                     else 
                        Log.e(TAG, "loaded_icon was null");
                    
                 else 
                    Log.e(TAG, "iconfile did not exist: "
                            + hydrant_icon_path);
                
             else 
                Log.e(TAG, "iconpath was empty on hydrant type: "
                        + hydrant_type);
            

            StringBuffer snippet = new StringBuffer();
            if (!address.isEmpty())
                snippet.append("\n" + address + " " + addressNumber);
            if (addres-s-remark.isEmpty())
                snippet.append("\n" + addres-s-remark);
            if (!remark.isEmpty())
                snippet.append("\n" + remark);

            markers.add(new MarkerOptions().position(position)
                    .title(hydrant_type).snippet(snippet.toString())
                    .icon(icon));

            publishProgress(markers.size());
        
        return markers;
    

    // Update the progress
    @Override
    protected void onProgressUpdate(Integer... values) 
        // set the current progress of the progress dialog
        progressDialog.setProgress(values[0]);
    

    // after executing the code in the thread
    @Override
    protected void onPostExecute(List<MarkerOptions> markers) 

        GoogleMap map = GoogleMapsModule.getInstance().getMap();

        for (MarkerOptions marker : markers) 
            if (marker != null)
            map.addMarker(marker);
        

        if (markers.size() == mHydrants.size()) 
            setAllHydrantAdded(true);
            setNearbyHydrantsAdded(true);
         else 
            setNearbyHydrantsAdded(true);
        
        Device.releaseOrientation((Activity) context);
    

当我调用任务时，我有一个 Hydrant 对象列表。要将列表解析为 AsyncTask，我将列表转换为数组：

        new LoadHydrantsToMapTask(hydrants.size()).execute(hydrants
            .toArray(new Hydrant[hydrants.size()]));