如何让的经度和纬度的android [英] how to get longitude and latitude in android

问题描述

我想找到我的当前位置的经度和纬度，但我一直得到的 NULL

 双纬度= loc.getLatitude（）; //导致的结果为空，所以无法知道经度和纬度
双LNG = loc.getLongitude（）; 的LocationManager的LocationManager =（的LocationManager）this.getSystemService（Context.LOCATION_SERVICE）;
    字符串提供商= LocationManager.GPS_PROVIDER;
    地点= locationManager.getLastKnownLocation（供应商）; //结果为空！
 

这是code，以获得GPS状态。它的工作原理罚款：

 公共无效onGpsStatusChanged（INT事件）{//获取GPS雕像
                的LocationManager的LocationManager =（的LocationManager）GpsActivity.this.getSystemService（Context.LOCATION_SERVICE）;
                GpsStatus状态= locationManager.getGpsStatus（NULL）;
                字符串satelliteInfo = updateGpsStatus（事件状态）;
                myTextView.setText（satelliteInfo）; //做工精细，搜索卫星：16
    }
    };
        私人字符串updateGpsStatus（INT事件，GpsStatus状态）{
            StringBuilder的SB2 =新的StringBuilder（）;
            如果（状态== NULL）{
                sb2.append（搜索卫星数字+0）;
            }否则如果（事件== GpsStatus.GPS_EVENT_SATELLITE_STATUS）{
                INT maxSatellites = status.getMaxSatellites（）;
                迭代器＆LT; GpsSatellite＆GT;它= status.getSatellites（）迭代器（）。
                numSatelliteList.clear（）;
                诠释计数= 0;
                而（it.hasNext（）及和放大器; COUNT＆LT; = maxSatellites）{
                    GpsSatellite S = it.next（）;
                    numSatelliteList.add（多个）;
                    算上++;
                }
                sb2.append（搜寻卫星编号：+ numSatelliteList.size（））;
            }
            返回sb2.toString（）;
        }
 

解决方案

getLastKnownLocation（）只返回最近的GPS定位，如果有的话。您需要实现一个LocationListener的，并使用<一个href=\"http://developer.android.com/reference/android/location/LocationManager.html#requestLocationUpdates%28java.lang.String,%20long,%20float,%20android.location.LocationListener%29\"><$c$c>LocationManager#requestLocationUpdates()获取一个新的位置。

---

实施基础：

 公共类示例扩展活动实现LocationListener的{
    的LocationManager mLocationManager;    @覆盖
    公共无效的onCreate（捆绑savedInstanceState）{
        super.onCreate（savedInstanceState）;
        的setContentView（R.layout.main）;        mLocationManager =（的LocationManager）getSystemService（Context.LOCATION_SERVICE）;        地点= mLocationManager.getLastKnownLocation（LocationManager.GPS_PROVIDER）;
        如果（位置！= NULL）{
            //做一些与最近的位置锁定
            //否则等待下面的更新
        }
        其他{
            mLocationManager.requestLocationUpdates（LocationManager.GPS_PROVIDER，0，0，这一点）;
        }
    }    @覆盖
    公共无效onLocationChanged（地点）{
        如果（位置！= NULL）{
            Log.v（位置发生改变，location.getLatitude（）+和+ location.getLongitude（））;
        }
    }
    //等。
}
 

I want to find the longitude and latitude of my current location, but I keep get NULL.

double lat = loc.getLatitude(); //Cause the result is null, so can't know longitude and latitude
double lng = loc.getLongitude();



 LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);  
    String provider = LocationManager.GPS_PROVIDER;  
    Location location = locationManager.getLastKnownLocation(provider); //result is null!

This is the code to get the GPS status. It works fine:

public void onGpsStatusChanged(int event) { // get the GPS statue  
                LocationManager locationManager = (LocationManager) GpsActivity.this.getSystemService(Context.LOCATION_SERVICE);  
                GpsStatus status = locationManager.getGpsStatus(null);  
                String satelliteInfo = updateGpsStatus(event, status);
                myTextView.setText(satelliteInfo);//work fine ,searched satellite:16
    }
    };
        private String updateGpsStatus(int event, GpsStatus status) {  
            StringBuilder sb2 = new StringBuilder("");  
            if (status == null) {  
                sb2.append("searched satellite number" +0);  
            } else if (event == GpsStatus.GPS_EVENT_SATELLITE_STATUS) {  
                int maxSatellites = status.getMaxSatellites();  
                Iterator<GpsSatellite> it = status.getSatellites().iterator();  
                numSatelliteList.clear();  
                int count = 0;  
                while (it.hasNext() && count <= maxSatellites) {  
                    GpsSatellite s = it.next();  
                    numSatelliteList.add(s);  
                    count++;  
                }  
                sb2.append("searched satellite number:" + numSatelliteList.size());  
            }
            return sb2.toString();  
        }

解决方案

getLastKnownLocation() only returns a recent GPS fix, if available. You need to implement a LocationListener and use LocationManager#requestLocationUpdates() to fetch a new location.

---

Basic implementation:

public class Example extends Activity implements LocationListener {
    LocationManager mLocationManager;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mLocationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        Location location = mLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        if(location != null) {
            // Do something with the recent location fix
            //  otherwise wait for the update below
        }
        else {
            mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
        }
    }

    @Override
    public void onLocationChanged(Location location) {
        if (location != null) {
            Log.v("Location Changed", location.getLatitude() + " and " + location.getLongitude());
        }
    }
    // etc..
}

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