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/