gps-Android GPS定位，得到徑緯度

Android GPS定位，得到徑緯度

為什麼location一直為NULL呢？由與是空
double lat = loc.getLatitude(); //徑緯度也就得不到了
double lng = loc.getLongitude();

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

以下是取得衛星數，可以正常工作

public void onGpsStatusChanged(int event) { // GPS狀態變化時的回調，如衛星數  
                LocationManager locationManager = (LocationManager) GpsActivity.this.getSystemService(Context.LOCATION_SERVICE);  
                GpsStatus status = locationManager.getGpsStatus(null); //取當前狀態  
                String satelliteInfo = updateGpsStatus(event, status);
                myTextView.setText(satelliteInfo);//正常，顯示:搜索到衛星個數:16
    }
    };
        private String updateGpsStatus(int event, GpsStatus status) {  
            StringBuilder sb2 = new StringBuilder("");  
            if (status == null) {  
                sb2.append("搜索到衛星個數：" +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("搜索到衛星個數：" + numSatelliteList.size());  
            }
            return sb2.toString();  
        }

在AVD上，這也許是好的~因為可以直接send latitiude...
誰有真機能定位的demo，室內能測最好，只需輸出當前徑緯度既可，感激不盡~

最佳回答：

getLastKnownLocation()只能返回最近的GPS方位，你需要實現一個LocationListener，使用 LocationManager#requestLocationUpdates()獲得新位置

基本實現：

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) {
            // 對最近的位置方位進行操作
            //  或者等待更新
        }
        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());
        }
    }
    // ……
}