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
在过去一年多的时间里，我使用GPS_PROVIDER和NETWORK_PROVIDER的组合来获取当前位置，它运行得很好，但从过去几个月开始，我在经过长时间的延迟后才获取位置，所以我改用了最新的API FusedLocationProviderClient，它运行的很好。
下面是我使用FusedLocationProviderClient编写的获取当前位置的类。在下面的代码中，我使用了一个计时器等待一段时间以获取当前位置，我安排了计时器15秒的延迟，您可以根据您的情况进行更改。
private static FusedLocationService ourInstance;
private final LocationRequest locationRequest;
private FusedLocationProviderClient mFusedLocationClient;
private Location mLastLocation;
private Context context;
private FindOutLocation findOutLocation;
private boolean callbackTriggered = false;
private Timer timer;
public static FusedLocationService getInstance(Context pContext) {
if (null == ourInstance) ourInstance = new FusedLocationService(pContext);
return ourInstance;
}
private FusedLocationService(Context pContext) {
context = pContext;
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(context);
locationRequest = getLocationRequest();
requestLocation(context);
}
public Location getLastKnownLocation() {
return mLastLocation;
}
private void requestLocation(Context context) {
if (ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return;
}
mFusedLocationClient.requestLocationUpdates(locationRequest, mLocationCallback, null);
mFusedLocationClient.getLastLocation().addOnSuccessListener(location -> {
if (location != null) {
mLastLocation = location;
triggerCallback(mLastLocation);
}
});
}
private LocationRequest getLocationRequest() {
LocationRequest locationRequest = new LocationRequest();
long INTERVAL = 10 * 1000;
long FASTEST_INTERVAL = 5 * 1000;
locationRequest.setInterval(INTERVAL);
locationRequest.setFastestInterval(FASTEST_INTERVAL);
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
return locationRequest;
}
private LocationCallback mLocationCallback = new LocationCallback() {
@Override
public void onLocationResult(LocationResult locationResult) {
for (Location location : locationResult.getLocations()) {
if (location != null) mLastLocation = location;
}
if (null != mLastLocation) triggerCallback(mLastLocation);
}
};
public static abstract class FindOutLocation {
public abstract void gotLocation(Location location);
}
@SuppressLint("MissingPermission")
public void findLocation(FindOutLocation findOutLocation) {
long TIMER_TIME_OUT = 15 * 1000;
this.findOutLocation = findOutLocation;
callbackTriggered = false;
try {
requestLocation(context);
timer = new Timer();
timer.schedule(new GetLastLocation(context), TIMER_TIME_OUT);
} catch (Exception e) {
e.printStackTrace();
}
}
private class GetLastLocation extends TimerTask {
Context context;
GetLastLocation(Context context) {
this.context = context;
}
@Override
public void run() {
triggerCallback(mLastLocation);
}
}
private void triggerCallback(Location location) {
if (null != location) mLastLocation = location;
if (!callbackTriggered && null != findOutLocation) {
callbackTriggered = true;
removeLocationUpdates();
findOutLocation.gotLocation(location);
findOutLocation = null;
}
}
private void removeLocationUpdates() {
if (null != timer) timer.cancel();
if (null != mFusedLocationClient)
mFusedLocationClient.removeLocationUpdates(mLocationCallback);
}
}
这是从活动中调用的，下面是代码
FusedLocationService.FindOutLocation findOutLocation = new FusedLocationService.FindOutLocation() {
@Override
public void gotLocation(Location currentLocation) {
if (currentLocation != null) {
/*TODO DO SOMETHING WITH CURRENT LOCATION*/
}
}
};
FusedLocationService.getInstance(this).findLocation(findOutLocation);
在AndroidManifest.xml中添加以下条目
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<!-- Needed only if your app targets Android 5.0 (API level 21) or higher. -->
<uses-feature android:name="android.hardware.location.gps" />
其他回答
实际上，我们可以使用两个提供商（GPS和网络）。他们只是分享一个公共听众：
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 10 * 1000, (float) 10.0, listener);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 90 * 1000, (float) 10.0, listener);
这是必要的，因为总是需要及时调用OnLocationChanged（）方法。
以下是我所做的：
首先，我检查启用了哪些提供程序。有些可能在设备上禁用，有些可能在应用程序清单中禁用。如果有任何提供程序可用，我将启动位置侦听器和超时计时器。在我的例子中，这是20秒，可能不够GPS，所以你可以放大它。如果我从位置侦听器获取更新，我将使用提供的值。我停止听众和计时器。如果我没有得到任何更新和计时器，我必须使用最近的已知值。我从可用的提供程序中获取最新的已知值，并选择其中最新的值。
以下是我如何使用我的课程：
LocationResult locationResult = new LocationResult(){
@Override
public void gotLocation(Location location){
//Got the location!
}
};
MyLocation myLocation = new MyLocation();
myLocation.getLocation(this, locationResult);
这里是MyLocation类：
import java.util.Timer;
import java.util.TimerTask;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
public class MyLocation {
Timer timer1;
LocationManager lm;
LocationResult locationResult;
boolean gps_enabled=false;
boolean network_enabled=false;
public boolean getLocation(Context context, LocationResult result)
{
//I use LocationResult callback class to pass location value from MyLocation to user code.
locationResult=result;
if(lm==null)
lm = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
//exceptions will be thrown if provider is not permitted.
try{gps_enabled=lm.isProviderEnabled(LocationManager.GPS_PROVIDER);}catch(Exception ex){}
try{network_enabled=lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);}catch(Exception ex){}
//don't start listeners if no provider is enabled
if(!gps_enabled && !network_enabled)
return false;
if(gps_enabled)
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListenerGps);
if(network_enabled)
lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListenerNetwork);
timer1=new Timer();
timer1.schedule(new GetLastLocation(), 20000);
return true;
}
LocationListener locationListenerGps = new LocationListener() {
public void onLocationChanged(Location location) {
timer1.cancel();
locationResult.gotLocation(location);
lm.removeUpdates(this);
lm.removeUpdates(locationListenerNetwork);
}
public void onProviderDisabled(String provider) {}
public void onProviderEnabled(String provider) {}
public void onStatusChanged(String provider, int status, Bundle extras) {}
};
LocationListener locationListenerNetwork = new LocationListener() {
public void onLocationChanged(Location location) {
timer1.cancel();
locationResult.gotLocation(location);
lm.removeUpdates(this);
lm.removeUpdates(locationListenerGps);
}
public void onProviderDisabled(String provider) {}
public void onProviderEnabled(String provider) {}
public void onStatusChanged(String provider, int status, Bundle extras) {}
};
class GetLastLocation extends TimerTask {
@Override
public void run() {
lm.removeUpdates(locationListenerGps);
lm.removeUpdates(locationListenerNetwork);
Location net_loc=null, gps_loc=null;
if(gps_enabled)
gps_loc=lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if(network_enabled)
net_loc=lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
//if there are both values use the latest one
if(gps_loc!=null && net_loc!=null){
if(gps_loc.getTime()>net_loc.getTime())
locationResult.gotLocation(gps_loc);
else
locationResult.gotLocation(net_loc);
return;
}
if(gps_loc!=null){
locationResult.gotLocation(gps_loc);
return;
}
if(net_loc!=null){
locationResult.gotLocation(net_loc);
return;
}
locationResult.gotLocation(null);
}
}
public static abstract class LocationResult{
public abstract void gotLocation(Location location);
}
}
可能有人也想修改我的逻辑。例如，如果您从网络提供商获得更新，不要停止侦听器，而是继续等待。GPS提供了更准确的数据，所以值得等待。如果计时器过去了，并且您从网络获得了更新，而不是GPS，那么您可以使用网络提供的值。
还有一种方法是使用LocationClienthttp://developer.android.com/training/location/retrieve-current.html.但它需要在用户设备上安装Google Play Services apk。
以下是我所做的：
首先，我检查是否启用了网络或GPS提供商。有些可能在设备上禁用，有些可能在应用程序清单中禁用。如果启用了任何提供程序，我将获取该提供程序的缓存最后位置，并启动该提供程序位置更新侦听器。有一种方法可以确定某个位置是否优于链接中提到的上次接收位置：-https://developer.android.com/guide/topics/location/strategies.html#BestEstimate如果我从位置侦听器获得更新，我会检查这个位置是否比以前接收的位置更好。以及如果它比将此位置替换为先前的最佳位置（mFinalLocation）更好。还有一个两分钟的处理程序（计时器），它最终会停止服务，在服务的onDestroy（）方法中，停止侦听每个提供程序的位置更新。
以下是服务代码。您可以根据需要的位置更新频率运行它。
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.support.annotation.Nullable;
import android.util.Log;
public class RecordLocationService extends Service {
private final String TAG = RecordLocationService.class.getSimpleName();
private final int TWO_MINUTES = 1000 * 60 * 2;
private LocationManager mLocationManager;
private MyLocationListener mLocationListeners[] = new MyLocationListener[]{
new MyLocationListener(LocationManager.NETWORK_PROVIDER),
new MyLocationListener(LocationManager.GPS_PROVIDER)
};
private Location mFinalLocation;
private class MyLocationListener implements LocationListener {
private String mProvider;
public MyLocationListener(String provider) {
Log.d(TAG, "LocationListener : " + provider);
mProvider = provider;
}
public String getProvider() {
return mProvider;
}
@Override
public void onLocationChanged(Location location) {
Log.d(TAG, "onLocationChanged : " + location);
if (isBetterLocation(location, mFinalLocation)) {
Log.d(TAG, "Setting current Final Location to recent most Location for Provider : " + location.getProvider());
Log.d(TAG, "Setting current Final Location to : " + location);
mFinalLocation = location;
} else {
Log.d(TAG, "Keeping current Final Location to previous Final Location");
}
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
Log.d(TAG, "onStatusChanged provider " + provider);
}
@Override
public void onProviderEnabled(String provider) {
Log.d(TAG, "onProviderEnabled provider " + provider);
}
@Override
public void onProviderDisabled(String provider) {
Log.d(TAG, "onProviderDisabled provider " + provider);
}
}
private Handler mStopServiceHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 1: {
stopSelf();
}
break;
}
}
};
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
super.onStartCommand(intent, flags, startId);
Log.d(TAG, "onStartCommand");
return START_STICKY;
}
@Override
public void onCreate() {
super.onCreate();
Log.d(TAG, "onCreate");
requestLocation();
mStopServiceHandler.sendEmptyMessageDelayed(1, TWO_MINUTES);
}
private void requestLocation() {
// Acquire a reference to the system Location Manager
if (mLocationManager == null) {
mLocationManager = (LocationManager) this.getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
}
try {
if (mLocationManager.getAllProviders().contains(LocationManager.NETWORK_PROVIDER) && mLocationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
Log.d(TAG, "Fetching Cached Location for Provider : " + LocationManager.NETWORK_PROVIDER);
Location cachedNetworkLocation = mLocationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (cachedNetworkLocation != null) {
Log.d(TAG, "Setting Final Location to Cached Location for Provider : " + LocationManager.NETWORK_PROVIDER);
Log.d(TAG, "Setting Final Location to : " + cachedNetworkLocation);
mFinalLocation = cachedNetworkLocation;
} else {
Log.d(TAG, "Cached Location for Provider : " + LocationManager.NETWORK_PROVIDER + " is NULL");
}
Log.d(TAG, "Requesting Location Update for Provider : " + LocationManager.NETWORK_PROVIDER);
mLocationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, mLocationListeners[0]);
}
} catch (SecurityException se) {
Log.e(TAG, se.getMessage(), se);
} catch (IllegalArgumentException iae) {
Log.e(TAG, iae.getMessage(), iae);
}
try {
if (mLocationManager.getAllProviders().contains(LocationManager.GPS_PROVIDER) && mLocationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
Log.d(TAG, "Fetching Cached Location for Provider : " + LocationManager.GPS_PROVIDER);
Location cachedGPSLocation = mLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (cachedGPSLocation != null) {
if (isBetterLocation(cachedGPSLocation, mFinalLocation)) {
Log.d(TAG, "Setting Final Location to Cached Location for Provider : " + LocationManager.GPS_PROVIDER);
Log.d(TAG, "Setting Final Location to : " + cachedGPSLocation);
mFinalLocation = cachedGPSLocation;
}
} else {
Log.d(TAG, "Cached Location for Provider : " + LocationManager.GPS_PROVIDER + " is NULL");
}
Log.d(TAG, "Requesting Location Update for Provider : " + LocationManager.GPS_PROVIDER);
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mLocationListeners[1]);
}
} catch (SecurityException se) {
Log.e(TAG, se.getMessage(), se);
} catch (IllegalArgumentException iae) {
Log.e(TAG, iae.getMessage(), iae);
}
}
/**
* Determines whether one Location reading is better than the current Location fix
*
* @param location The new Location that you want to evaluate
* @param currentBestLocation The current Location fix, to which you want to compare the new one
*/
protected boolean isBetterLocation(Location location, Location currentBestLocation) {
if (currentBestLocation == null) {
// A new location is always better than no location
return true;
}
// Check whether the new location fix is newer or older
long timeDelta = location.getTime() - currentBestLocation.getTime();
boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;
boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;
boolean isNewer = timeDelta > 0;
// If it's been more than two minutes since the current location, use the new location
// because the user has likely moved
if (isSignificantlyNewer) {
return true;
// If the new location is more than two minutes older, it must be worse
} else if (isSignificantlyOlder) {
return false;
}
// Check whether the new location fix is more or less accurate
int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation.getAccuracy());
boolean isLessAccurate = accuracyDelta > 0;
boolean isMoreAccurate = accuracyDelta < 0;
boolean isSignificantlyLessAccurate = accuracyDelta > 200;
// Check if the old and new location are from the same provider
boolean isFromSameProvider = isSameProvider(location.getProvider(),
currentBestLocation.getProvider());
// Determine location quality using a combination of timeliness and accuracy
if (isMoreAccurate) {
return true;
} else if (isNewer && !isLessAccurate) {
return true;
} else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) {
return true;
}
return false;
}
/**
* Checks whether two providers are the same
*/
private boolean isSameProvider(String provider1, String provider2) {
if (provider1 == null) {
return provider2 == null;
}
return provider1.equals(provider2);
}
@Override
public void onDestroy() {
super.onDestroy();
Log.d(TAG, "onDestroy");
if (mLocationManager != null) {
for (int i = 0; i < mLocationListeners.length; i++) {
try {
Log.d(TAG, "Removing Location Update for Provider : " + mLocationListeners[i].getProvider());
mLocationManager.removeUpdates(mLocationListeners[i]);
} catch (Exception ex) {
Log.e(TAG, "fail to remove location listeners, ignore", ex);
}
}
}
}
}
Kotlin版本的@Fedor Greate回答：
类的用法：
val locationResult = object : MyLocation.LocationResult() {
override fun gotLocation(location: Location?) {
val lat = location!!.latitude
val lon = location.longitude
Toast.makeText(context, "$lat --SLocRes-- $lon", Toast.LENGTH_SHORT).show()
}
}
val myLocation = MyLocation()
myLocation.getLocation(inflater.context, locationResult)
MyLocation类：
class MyLocation {
internal lateinit var timer1: Timer
internal var lm: LocationManager? = null
internal lateinit var locationResult: LocationResult
internal var gps_enabled = false
internal var network_enabled = false
internal var locationListenerGps: LocationListener = object : LocationListener {
override fun onLocationChanged(location: Location) {
timer1.cancel()
locationResult.gotLocation(location)
lm!!.removeUpdates(this)
lm!!.removeUpdates(locationListenerNetwork)
}
override fun onProviderDisabled(provider: String) {}
override fun onProviderEnabled(provider: String) {}
override fun onStatusChanged(provider: String, status: Int, extras: Bundle) {}
}
internal var locationListenerNetwork: LocationListener = object : LocationListener {
override fun onLocationChanged(location: Location) {
timer1.cancel()
locationResult.gotLocation(location)
lm!!.removeUpdates(this)
lm!!.removeUpdates(locationListenerGps)
}
override fun onProviderDisabled(provider: String) {}
override fun onProviderEnabled(provider: String) {}
override fun onStatusChanged(provider: String, status: Int, extras: Bundle) {}
}
fun getLocation(context: Context, result: LocationResult): Boolean {
//I use LocationResult callback class to pass location value from MyLocation to user code.
locationResult = result
if (lm == null)
lm = context.getSystemService(Context.LOCATION_SERVICE) as LocationManager?
//exceptions will be thrown if provider is not permitted.
try {
gps_enabled = lm!!.isProviderEnabled(LocationManager.GPS_PROVIDER)
} catch (ex: Exception) {
}
try {
network_enabled = lm!!.isProviderEnabled(LocationManager.NETWORK_PROVIDER)
} catch (ex: Exception) {
}
//don't start listeners if no provider is enabled
if (!gps_enabled && !network_enabled)
return false
if (ActivityCompat.checkSelfPermission(context,
Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED ||
ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) run {
ActivityCompat.requestPermissions(context as Activity,
arrayOf(Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION), 111)
}
if (gps_enabled)
lm!!.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0f, locationListenerGps)
if (network_enabled)
lm!!.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0f, locationListenerNetwork)
timer1 = Timer()
timer1.schedule(GetLastLocation(context), 20000)
return true
}
internal inner class GetLastLocation(var context: Context) : TimerTask() {
override fun run() {
lm!!.removeUpdates(locationListenerGps)
lm!!.removeUpdates(locationListenerNetwork)
var net_loc: Location? = null
var gps_loc: Location? = null
if (ActivityCompat.checkSelfPermission(context,
Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED ||
ActivityCompat.checkSelfPermission(context, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED
) run {
ActivityCompat.requestPermissions(context as Activity,
arrayOf(Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION),111)
}
if (gps_enabled)
gps_loc = lm!!.getLastKnownLocation(LocationManager.GPS_PROVIDER)
if (network_enabled)
net_loc = lm!!.getLastKnownLocation(LocationManager.NETWORK_PROVIDER)
//if there are both values use the latest one
if (gps_loc != null && net_loc != null) {
if (gps_loc.getTime() > net_loc.getTime())
locationResult.gotLocation(gps_loc)
else
locationResult.gotLocation(net_loc)
return
}
if (gps_loc != null) {
locationResult.gotLocation(gps_loc)
return
}
if (net_loc != null) {
locationResult.gotLocation(net_loc)
return
}
locationResult.gotLocation(null)
}
}
abstract class LocationResult {
abstract fun gotLocation(location: Location?)
}
}
通过使用FusedLocationProviderApi，这是最新的API，也是在Android中获取位置的最佳可能性。将其添加到build.gradle文件中
dependencies {
compile 'com.google.android.gms:play-services:6.5.87'
}
您可以通过此url获取完整的源代码http://javapapers.com/android/android-location-fused-provider/
