Android上的LocationManager API似乎对一个只需要偶尔粗略估计用户位置的应用程序来说有点麻烦。
我正在开发的应用程序本身并不是一个定位应用程序，但它确实需要获取用户的位置，以便显示附近企业的列表。它不需要担心用户是否在移动或类似的事情。
以下是我想做的：
向用户显示附近位置的列表。预加载用户的位置，以便在“活动X”中需要它时，它将可用。我并不特别关心更新的准确性或频率。只要不太远，只要抓住一个位置就足够了。也许如果我想变得更漂亮，我会每隔几分钟左右更新一次位置，但这不是一个很大的优先事项。适用于任何具有GPS或网络位置提供商的设备。
这似乎并不难，但在我看来，我必须组建两个不同的位置提供商（GPS和NETWORK），并管理每个提供商的生命周期。不仅如此，我还必须在多个活动中复制相同的代码以满足#2。过去，我曾尝试使用getBestProvider（）将解决方案简化为仅使用一个位置提供程序，但这似乎只提供了最好的“理论”提供程序，而不是实际会为您提供最佳结果的提供程序。
有没有更简单的方法来实现这一点？
当前回答
你可以一直使用LocationManager.getLastKnownLocation（），但就像它说的那样，它可能已经过时了。
获取一般位置的一个简单方法是注册网络（通常很快）。
LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER, 1000, 1000, this);
然后做
locationManager.removeUpdates(this);
在侦听器的onLocationChanged（）方法中。
其他回答
在Activity Class中创建自定义方法：
private void getTheUserPermission() {
ActivityCompat.requestPermissions(this, new String[]
{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION);
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
LocationGetter locationGetter = new LocationGetter(FreshMenuSearchActivity.this, REQUEST_LOCATION, locationManager);
if (!locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
locationGetter.OnGPS();
} else {
locationGetter.getLocation();
}
}
生成用户定义的类名LocationGetter：-
public class LocationGetter {
private int REQUEST_LOCATION;
private FreshMenuSearchActivity mContext;
private LocationManager locationManager;
private Geocoder geocoder;
public LocationGetter(FreshMenuSearchActivity mContext, int requestLocation, LocationManager locationManager) {
this.mContext = mContext;
this.locationManager = locationManager;
this.REQUEST_LOCATION = requestLocation;
}
public void getLocation() {
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext,
Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(mContext, new String[]
{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION);
} else {
Location LocationGps = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
Location LocationNetwork = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
Location LocationPassive = locationManager.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
if (LocationGps != null) {
double lat = LocationGps.getLatitude();
double longi = LocationGps.getLongitude();
getTheAddress(lat, longi);
} else if (LocationNetwork != null) {
double lat = LocationNetwork.getLatitude();
double longi = LocationNetwork.getLongitude();
getTheAddress(lat, longi);
} else if (LocationPassive != null) {
double lat = LocationPassive.getLatitude();
double longi = LocationPassive.getLongitude();
getTheAddress(lat, longi);
} else {
Toast.makeText(mContext, "Can't Get Your Location", Toast.LENGTH_SHORT).show();
}
}
}
private void getTheAddress(double latitude, double longitude) {
List<Address> addresses;
geocoder = new Geocoder(mContext, Locale.getDefault());
try {
addresses = geocoder.getFromLocation(latitude, longitude, 1);
String address = addresses.get(0).getAddressLine(0);
String city = addresses.get(0).getLocality();
String state = addresses.get(0).getAdminArea();
String country = addresses.get(0).getCountryName();
String postalCode = addresses.get(0).getPostalCode();
String knownName = addresses.get(0).getFeatureName();
Log.d("neel", address);
} catch (IOException e) {
e.printStackTrace();
}
}
public void OnGPS() {
final AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
builder.setMessage("Enable GPS").setCancelable(false).setPositiveButton("YES", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
mContext.startActivity(new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS));
}
}).setNegativeButton("NO", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
final AlertDialog alertDialog = builder.create();
alertDialog.show();
}
}
我已经创建了一个小应用程序，并逐步描述以获取当前位置GPS坐标。
以下URL中的完整示例源代码：
获取当前位置坐标，城市名称-在Android中
查看其工作原理：
我们只需要在清单文件中添加此权限<uses permission android:name=“android.permission.ACCESS_FINE_LOCATION”></使用权限>并像这样创建LocationManager实例LocationManager LocationManager=（LocationManager）getSystemService（Context.LOCATION_SERVICE）；检查GPS是否已启用然后实现LocationListener和Get CoordinatesLocationListener LocationListener=新的MyLocationListeners（）；locationManager.requestLocationUpdates（LocationManager.GPS_PROVIDER，5000，10，locationListener）；下面是要做的示例代码
/*----------Listener class to get coordinates ------------- */
private class MyLocationListener implements LocationListener {
@Override
public void onLocationChanged(Location loc) {
editLocation.setText("");
pb.setVisibility(View.INVISIBLE);
Toast.makeText(
getBaseContext(),
"Location changed: Lat: " + loc.getLatitude() + " Lng: "
+ loc.getLongitude(), Toast.LENGTH_SHORT).show();
String longitude = "Longitude: " + loc.getLongitude();
Log.v(TAG, longitude);
String latitude = "Latitude: " + loc.getLatitude();
Log.v(TAG, latitude);
/*-------to get City-Name from coordinates -------- */
String cityName = null;
Geocoder gcd = new Geocoder(getBaseContext(), Locale.getDefault());
List<Address> addresses;
try {
addresses = gcd.getFromLocation(loc.getLatitude(),
loc.getLongitude(), 1);
if (addresses.size() > 0)
System.out.println(addresses.get(0).getLocality());
cityName = addresses.get(0).getLocality();
} catch (IOException e) {
e.printStackTrace();
}
String s = longitude + "\n" + latitude + "\n\nMy Current City is: "
+ cityName;
editLocation.setText(s);
}
@Override
public void onProviderDisabled(String provider) {}
@Override
public void onProviderEnabled(String provider) {}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {}
}
public static Location getBestLocation(Context ctxt) {
Location gpslocation = getLocationByProvider(
LocationManager.GPS_PROVIDER, ctxt);
Location networkLocation = getLocationByProvider(
LocationManager.NETWORK_PROVIDER, ctxt);
Location fetchedlocation = null;
// if we have only one location available, the choice is easy
if (gpslocation != null) {
Log.i("New Location Receiver", "GPS Location available.");
fetchedlocation = gpslocation;
} else {
Log.i("New Location Receiver",
"No GPS Location available. Fetching Network location lat="
+ networkLocation.getLatitude() + " lon ="
+ networkLocation.getLongitude());
fetchedlocation = networkLocation;
}
return fetchedlocation;
}
/**
* get the last known location from a specific provider (network/gps)
*/
private static Location getLocationByProvider(String provider, Context ctxt) {
Location location = null;
// if (!isProviderSupported(provider)) {
// return null;
// }
LocationManager locationManager = (LocationManager) ctxt
.getSystemService(Context.LOCATION_SERVICE);
try {
if (locationManager.isProviderEnabled(provider)) {
location = locationManager.getLastKnownLocation(provider);
}
} catch (IllegalArgumentException e) {
Log.i("New Location Receiver", "Cannot access Provider " + provider);
}
return location;
}
在android系统中获取位置更新需要很多东西，需要大量的bolierplate代码。
你需要照顾好
Google Play服务可用性检查，更新Google play服务，如果它是旧的或不可用GoogleApiClient的对话框创建及其连接、断开等回调。停止并释放用于位置更新的资源处理位置权限方案检查位置服务是否打开或关闭获取最新位置也不是那么容易如果在一定时间后未找到位置，则回退到最后一个已知位置
我已经创建了Android EasyLocation（小型Android库），它将处理所有这些事情，您可以专注于业务逻辑。
您只需要扩展EasyLocationActivity
requestSingleLocationFix(easyLocationRequest);
or
requestLocationUpdates(easyLocationRequest);
点击此处查看示例应用程序和所需步骤https://github.com/akhgupta/Android-EasyLocation
对@Fedor解决方案的改进。我们可以使用位置管理器的requestSingleUpdate方法，而不是使用“0”时间间隔和“0”距离请求位置。更新的代码（kotlin版本）
import android.annotation.SuppressLint
import android.content.Context
import android.location.Criteria
import android.location.Location
import android.location.LocationListener
import android.location.LocationManager
import android.os.Bundle
import java.util.*
@SuppressLint("MissingPermission")
class AppLocationProvider {
private lateinit var timer: Timer
private var locationManager: LocationManager? = null
private lateinit var locationCallBack: LocationCallBack
private var gpsEnabled = false
private var networkEnabled = false
private var locationListener: LocationListener = object : LocationListener {
override fun onLocationChanged(location: Location) {
timer.cancel()
locationCallBack.locationResult(location)
}
override fun onProviderDisabled(provider: String) {}
override fun onProviderEnabled(provider: String) {}
override fun onStatusChanged(provider: String, status: Int, extras: Bundle) {}
}
fun getLocation(context : Context, callBack: LocationCallBack): Boolean {
locationCallBack = callBack
if (locationManager == null)
locationManager = context.getSystemService(Context.LOCATION_SERVICE) as LocationManager?
//exceptions will be thrown if provider is not permitted.
try {
gpsEnabled = locationManager!!.isProviderEnabled(LocationManager.GPS_PROVIDER)
} catch (ex: Exception) {
ex.printStackTrace()
}
try {
networkEnabled = locationManager!!.isProviderEnabled(LocationManager.NETWORK_PROVIDER)
} catch (ex: Exception) {
ex.printStackTrace()
}
//don't start listeners if no provider is enabled
if (!gpsEnabled && !networkEnabled)
return false
val criteria = Criteria()
if (gpsEnabled) {
criteria.accuracy = Criteria.ACCURACY_FINE
} else {
criteria.accuracy = Criteria.ACCURACY_COARSE
}
locationManager!!.requestSingleUpdate(criteria, locationListener, null)
timer = Timer()
timer.schedule(GetLastKnownLocation(), 5000)
return true
}
inner class GetLastKnownLocation : TimerTask() {
override fun run() {
locationManager!!.removeUpdates(locationListener)
var netLoc: Location? = null
var gpsLoc: Location? = null
if (gpsEnabled)
gpsLoc = locationManager!!.getLastKnownLocation(LocationManager.GPS_PROVIDER)
if (networkEnabled)
netLoc = locationManager!!.getLastKnownLocation(LocationManager.NETWORK_PROVIDER)
//check which value use the latest one
if (gpsLoc != null && netLoc != null) {
if (gpsLoc.time > netLoc.time)
locationCallBack.locationResult(gpsLoc)
else
locationCallBack.locationResult(netLoc)
return
}
if (gpsLoc != null) {
locationCallBack.locationResult(gpsLoc)
return
}
if (netLoc != null) {
locationCallBack.locationResult(netLoc)
return
}
locationCallBack.locationResult(null)
}
}
interface LocationCallBack {
fun locationResult(location: Location?)
}
}
要获取位置，只需调用getLocation方法-
AppLocationProvider().getLocation(context, object : AppLocationProvider.LocationCallBack {
override fun locationResult(location: Location?) {
// use location, this might get called in a different thread if a location is a last known location. In that case, you can post location on main thread
}
})
注：在调用getLocation方法之前，必须授予所需的位置权限。
