Question

我想每5分钟获取一次用户的位置，因此我使用以下代码创建了Service：

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.util.Log;

public class Tracker extends Service {

    private SharedPreferences prefs;
    private LocationManager locationManager;
    private long minTime = 300000; // miliseconds
    private float minDistance = 10; // meters
    private boolean gpsStatus;
    private boolean networkStatus;

    @Override
    public void onCreate() {
        Log.i("Location2", "Location: Created");
        super.onCreate();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i("Location2", "Location: Started");

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

        gpsStatus = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
        networkStatus = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
        locationManager.requestLocationUpdates(getProviderName(), minTime, minDistance, locationListener);

        return Service.START_STICKY;
    }

    private void resetLocationProvider() {
        Log.e("Location2", "Provider Reset");
        deleteLocationListener();
        locationManager.requestLocationUpdates(getProviderName(), minTime, minDistance, locationListener);
    }

    private void deleteLocationListener() {
        locationManager.removeUpdates(locationListener);
    }

    private LocationListener locationListener = new LocationListener() {

        @Override
        public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
        }

        @Override
        public void onProviderEnabled(String provider) {
            resetLocationProvider();
            Log.e("Location2", "Provider Enabled: " + provider);
        }

        @Override
        public void onProviderDisabled(String provider) {
            resetLocationProvider();
            Log.e("Location2", "Provider Disabled: " + provider);
        }

        @Override
        public void onLocationChanged(Location location) {
            Log.i("Location2", "Location Time: " + TimeToDate.getDate(location.getTime(), "yyyy-MM-dd HH:mm:ss"));
            Log.i("Location2", "Location Provider: " + location.getProvider());
            Log.i("Location2", "Location Accuracy: " + location.getAccuracy());
            Log.i("Location2", "Location Latitude: " + location.getLatitude());
            Log.i("Location2", "Location Longitude: " + location.getLongitude());

            if (gpsStatus != locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
                gpsStatus = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
                resetLocationProvider();
                return;
            }

            if (networkStatus != locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
                networkStatus = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
                resetLocationProvider();
            }
        }
    };

    private String getProviderName() {
        LocationManager locationManager = (LocationManager) this
                .getSystemService(Context.LOCATION_SERVICE);

        Criteria criteria = new Criteria();
        criteria.setPowerRequirement(Criteria.POWER_MEDIUM); // Chose your desired power consumption level.
        criteria.setAccuracy(Criteria.ACCURACY_FINE); // Choose your accuracy requirement.
        criteria.setSpeedRequired(false); // Chose if speed for first location fix is required.
        criteria.setAltitudeRequired(false); // Choose if you use altitude.
        criteria.setBearingRequired(false); // Choose if you use bearing.
        criteria.setCostAllowed(false); // Choose if this provider can waste money :-)

        // Provide your criteria and flag enabledOnly that tells
        // LocationManager only to return active providers.
        return locationManager.getBestProvider(criteria, true);
    }

    @Override
    public void onDestroy() {
        deleteLocationListener();
        super.onDestroy();
    };

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

}

如图所示，我使用了minTime 300,000 ms，但我每隔约20秒而不是每5分钟获得一个位置。正如documentation所说：

位置更新之间经过的时间永远不会少于 minTime，虽然它可能更多取决于位置提供者实施和其他应用程序请求的更新间隔

我也知道，active provider不是background process的好选择。但是，我的代码出了什么问题？

Answer 1

根据this answer，我将代码更改为：

        @Override
        public void onLocationChanged(Location location) {
            if (location != null) {
                if (location.getProvider().equals(LocationManager.GPS_PROVIDER) && android.os.Build.VERSION.SDK_INT < 16) {
                    Log.i("TEST", "DATE: " + TimeToDate.getDate(location.getTime(), "yyyy-MM-dd HH:mm:ss"));
                    Log.i("TEST", "LAT: " + location.getLatitude());
                    Log.i("TEST", "LONG: " + location.getLongitude());
                    locationManager.removeUpdates(locationListener);
                    new Handler().postDelayed(new Runnable() {

                        @Override
                        public void run() {
                            locationManager.requestLocationUpdates(getProviderName(), minTime, minDistance, locationListener);
                        }
                    }, minTime);
                }
                ...

现在它有效。

LocationManager minTime无法正常工作

1 个答案: