Вот сценарий, который привел к получению нулевого расположения:.Null места при попытке Google Maps демки
- Перейти к меню Настройки -> Расположение доступа> Выключить
WiFi & mobile network location
. - Открыть демонстрационное приложение.
- Выберите
MyLocationDemoActivity
. - Нажмите на кнопку
My Location
. Вы получитеLocation: null
в тосте.
Однако, если вы включите WiFi & mobile network location
, место вернется. Итак, вот некоторые вопросы:
- В моем приложении, я должен предположить, что
WiFi & mobile network location
включен по умолчанию (то же самое демо сделал)? - Если нет, как определить это и показать соответствующее сообщение?
- И хорошо ли хранить последнее место в (например,
SharedPreference
) для использования, когда сетевое местоположение отключено?
Это MyLocationDemoActivity
для справки:
/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.mapdemo;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient.ConnectionCallbacks;
import com.google.android.gms.common.GooglePlayServicesClient.OnConnectionFailedListener;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationClient;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
/**
* This demo shows how GMS Location can be used to check for changes to the users location. The
* "My Location" button uses GMS Location to set the blue dot representing the users location. To
* track changes to the users location on the map, we request updates from the
* {@link LocationClient}.
*/
public class MyLocationDemoActivity extends FragmentActivity
implements ConnectionCallbacks, OnConnectionFailedListener, LocationListener {
private GoogleMap mMap;
private LocationClient mLocationClient;
private TextView mMessageView;
// These settings are the same as the settings for the map. They will in fact give you updates at
// the maximal rates currently possible.
private static final LocationRequest REQUEST = LocationRequest.create()
.setInterval(5000) // 5 seconds
.setFastestInterval(16) // 16ms = 60fps
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_location_demo);
mMessageView = (TextView) findViewById(R.id.message_text);
}
@Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
setUpLocationClientIfNeeded();
mLocationClient.connect();
}
@Override
public void onPause() {
super.onPause();
if (mLocationClient != null) {
mLocationClient.disconnect();
}
}
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
mMap.setMyLocationEnabled(true);
}
}
}
private void setUpLocationClientIfNeeded() {
if (mLocationClient == null) {
mLocationClient = new LocationClient(
getApplicationContext(),
this, // ConnectionCallbacks
this); // OnConnectionFailedListener
}
}
/**
* Button to get current Location. This demonstrates how to get the current Location as required,
* without needing to register a LocationListener.
*/
public void showMyLocation(View view) {
if (mLocationClient != null && mLocationClient.isConnected()) {
String msg = "Location = " + mLocationClient.getLastLocation();
Toast.makeText(getApplicationContext(), msg, Toast.LENGTH_SHORT).show();
}
}
/**
* Implementation of {@link LocationListener}.
*/
@Override
public void onLocationChanged(Location location) {
mMessageView.setText("Location = " + location);
}
/**
* Callback called when connected to GCore. Implementation of {@link ConnectionCallbacks}.
*/
@Override
public void onConnected(Bundle connectionHint) {
mLocationClient.requestLocationUpdates(
REQUEST,
this); // LocationListener
}
/**
* Callback called when disconnected from GCore. Implementation of {@link ConnectionCallbacks}.
*/
@Override
public void onDisconnected() {
// Do nothing
}
/**
* Implementation of {@link OnConnectionFailedListener}.
*/
@Override
public void onConnectionFailed(ConnectionResult result) {
// Do nothing
}
}
Я думаю, что мы должны использовать [LocationClient] (http://developer.android.com/reference/com/google/android/gms/location/LocationClient.html) вместо [ LocationManager] (http://developer.android.com/reference/android/location/LocationManager.html) с версии 2, не так ли? – iTurki
Не обязательно, кроме: 'LocationClient' полагается на' Службы Google Play ', которые могут быть недоступны на каждом устройстве. – Androiderson
Я полагаюсь на это. В моем приложении используются карты Google. – iTurki