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

其中一些人现在已经过时了,所以我回答说,

FusedLocationProviderClient fusedLocationProviderClient; //set global variable
Location currentLocation;//set global var
private boolean mLocationPermissionGranted; //set global var
 fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(getContext()); //write this oncreate
        fetchLastLocation();  // call the funct for current location
//here is the function
private void fetchLastLocation() {

    if (ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.ACCESS_FINE_LOCATION)
            != PackageManager.PERMISSION_GRANTED) {

        ActivityCompat.requestPermissions(getActivity(),new String[]{
                Manifest.permission.ACCESS_FINE_LOCATION},REQUEST_CODE);
        return;
    }else {
        mLocationPermissionGranted=true;
    }
    Task<Location> task= fusedLocationProviderClient.getLastLocation();
    task.addOnSuccessListener(new OnSuccessListener<Location>() {
        @Override
        public void onSuccess(Location location) {
            if(location != null){
                currentLocation =location;
               Toast.makeText(getContext(), currentLocation.getLatitude()+"" +
                        " "+currentLocation.getLongitude(), 
                   Toast.LENGTH_SHORT).show();
//if you want to show in google maps
                SupportMapFragment supportMapFragment =(SupportMapFragment)
                        getChildFragmentManager().findFragmentById(R.id.map);
                supportMapFragment.getMapAsync(MapsFragment.this);
            }
        }
    });


}

其他回答

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。

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) {}
}

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。

编辑:更新了Google Play Services库中的最新位置服务API(2014年7月)

我建议您使用新的位置服务API,该API可从Google Play Services库中获得,它提供了一个更强大的高级框架,可自动执行位置提供商选择和电源管理等任务。根据官方文档:“……位置API使您可以轻松地构建位置感知应用程序,而无需关注底层位置技术的细节。它们还允许您通过使用设备硬件的所有功能来最小化功耗。”

有关更多信息,请访问:使您的应用程序位置感知

要查看使用最新位置服务API的完整示例,请访问:Android LocationClient类已弃用,但在文档中使用

我已经在demonuts.com上写了详细的教程,介绍了当前位置。您可以在这里找到更多描述,也可以下载整个演示源代码以更好地理解。

这里已经有很多答案,但我想展示使用Google API获取位置的最新方法,这样新程序员就可以使用新方法:

首先,将其放在gradle文件中

compile 'com.google.android.gms:play-services:8.4.0'

然后实现必要的接口

public class MainActivity  extends BaseActivitiy implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, com.google.android.gms.location.LocationListener

声明实例

  private GoogleApiClient mGoogleApiClient;
  private Location mLocation;
  private LocationManager locationManager;
  private LocationRequest mLocationRequest;

将其放入onCreate()中

 mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

最后,重写必要的方法

 @Override
    public void onConnected(Bundle bundle) {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    ActivityCompat#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for ActivityCompat#requestPermissions for more details.
            return;
        }
        mLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
        if(mLocation == null){
            startLocationUpdates();
        }
        if (mLocation != null) {
            double latitude = mLocation.getLatitude();
            double longitude = mLocation.getLongitude();
        } else {
            // Toast.makeText(this, "Location not Detected", Toast.LENGTH_SHORT).show();
        }
    }

    protected void startLocationUpdates() {
        // Create the location request
        mLocationRequest = LocationRequest.create()
                .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
                .setInterval(UPDATE_INTERVAL)
                .setFastestInterval(FASTEST_INTERVAL);
        // Request location updates
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    ActivityCompat#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for ActivityCompat#requestPermissions for more details.
            return;
        }
        LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
                mLocationRequest, this);
        Log.d("reque", "--->>>>");
    }

    @Override
    public void onConnectionSuspended(int i) {
        Log.i(TAG, "Connection Suspended");
        mGoogleApiClient.connect();
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
        Log.i(TAG, "Connection failed. Error: " + connectionResult.getErrorCode());
    }

    @Override
    public void onStart() {
        super.onStart();
        mGoogleApiClient.connect();
    }

    @Override
    public void onStop() {
        super.onStop();
        if (mGoogleApiClient.isConnected()) {
            mGoogleApiClient.disconnect();
        }
    }
    @Override
    public void onLocationChanged(Location location) {

    }

在运行应用程序之前,不要忘记在设备中启动GPS。