android - wifi 提供商 onLocationChanged 从未被调用

Question

我遇到了一个奇怪的问题。我使用 wifi 来检索用户位置。我已经在几部手机上进行了测试；在其中一些上，我永远无法获得位置更新。似乎从未调用过 onLocationChanged 方法。我的代码附在下面..任何建议表示赞赏!!!

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

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

  String provider = locationManager.NETWORK_PROVIDER;
  Location l = locationManager.getLastKnownLocation(provider);

  updateWithNewLocation(l);

  locationManager.requestLocationUpdates(provider, 0, 0,
                                       locationListener);
}

private void updateWithNewLocation(Location location) {
  TextView myLocationText;
  myLocationText = (TextView)findViewById(R.id.myLocationText);

  String latLongString = "No location found";
  if (location != null) {
    double lat = location.getLatitude();
    double lng = location.getLongitude();
    latLongString = "Lat:" + lat + "\nLong:" + lng;
  }

  myLocationText.setText("Your Current Position is:\n" +
                       latLongString);
}

private final LocationListener locationListener = new LocationListener() {
  public void onLocationChanged(Location location) {
    updateWithNewLocation(location);
    Log.i("onLocationChanged", "onLocationChanged");
    Toast.makeText(getApplicationContext(), "location changed", 
            Toast.LENGTH_SHORT).show();
  }

public void onProviderDisabled(String provider) {}
public void onProviderEnabled(String provider) {}
public void onStatusChanged(String provider, int status, 
                            Bundle extras) {}

};

list

<uses-permission
android:name="android.permission.ACCESS_FINE_LOCATION"
/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/> 

Answer 1

我的猜测是，您无法从中获取位置更新的手机没有正确的数据连接。网络提供商需要 GSM/3G 或 WiFi 数据连接，才能使用手机的手机/wifi 数据从 Google 服务器检索定位信息。您可以使用以下方法进行检查。

public boolean isOnline() {
ConnectivityManager cm =
    (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnectedOrConnecting()) {
    return true;
}
return false;