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

这是我请求用户权限的方式。

在AndroidManifest.xml中的应用程序标记外添加这些权限请求。

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

然后在App Gradle文件中添加Google的位置依赖项。

implementation 'com.google.android.gms:play-services-location:15.0.0'

现在声明一些全局变量。

private lateinit var mFusedLocationProvider:FusedLocationProviderClient
private lateinit var mLocationCallback: LocationCallback
private lateinit var mLocationRequest: LocationRequest
private var mLocationPermissionGranted:Boolean = false

在活动的OnCreate方法中(我无法正确格式化代码,对此深表歉意)

mFusedLocationProvider = LocationServices.getFusedLocationProviderClient(this)

//Location Callback
mLocationCallback = object: LocationCallback(){
 override fun onLocationResult(p0: LocationResult?) {
  if(p0==null){
     //todo(request user to enable location from settings then remove return)
     return
  }else{
      getDeviceLocation()
       }
  }
}

//Location Request
mLocationRequest = LocationRequest.create()
mLocationRequest.priority = LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY
//Set the Interval for Latest Interval Update
mLocationRequest.interval = 5000
//Set How Many Location Updated you Want
mLocationRequest.numUpdates = 1

getLocationPermission()
getDeviceLocation()

现在创建这两个函数。

 private fun getLocationPermission() {

            val permission:Array<String> = arrayOf(android.Manifest.permission.ACCESS_FINE_LOCATION,android.Manifest.permission.ACCESS_COARSE_LOCATION)
            if(ContextCompat.checkSelfPermission(applicationContext,Constant.FINE_LOCATION)== PermissionChecker.PERMISSION_GRANTED){
                if(ContextCompat.checkSelfPermission(applicationContext,Constant.COARSE_LOCATION)== PermissionChecker.PERMISSION_GRANTED){
                    mLocationPermissionGranted = true
                }
            }else{
                ActivityCompat.requestPermissions(this,permission,Constant.LOCATION_REQUEST_CODE)
            }

    }

第二种方法

private fun getDeviceLocation() {
        try{
            if(mLocationPermissionGranted){

                mFusedLocationProvider.lastLocation.addOnCompleteListener(this,{task: Task<Location> ->
                    if(task.isSuccessful){
                        var currentLocation: Location? = task.result
                        if(currentLocation!=null){

                            Log.i("Location","Latitude is ${currentLocation.latitude} and Longitude" +
                                    "${currentLocation.longitude}")
                        }

                        else
                            mFusedLocationProvider.requestLocationUpdates(mLocationRequest,mLocationCallback,null)
                    }
                })
            }
        }catch (e:SecurityException){
            Log.e("Error", "Security Exception ${e.message}")
        }
    }

对于常量.kt

class Constant{
    companion object {

        //Location Request Settings
        const val SET_INTERVAL:Long = 2000
        const val NUM_UPDATES:Int = 1

        //Location Permission
        const val FINE_LOCATION:String = android.Manifest.permission.ACCESS_FINE_LOCATION
        const val COARSE_LOCATION:String = android.Manifest.permission.ACCESS_COARSE_LOCATION
    }
}

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。

尽管这里已经给出了答案。我只是想向全世界分享这一点,以防遇到这种情况。

我的要求是,我需要在最长30到35秒内获取用户的当前位置,所以下面是我根据Nirav Ranpara的回答制定的解决方案。

1.我制作了MyLocationManager.java类,该类处理所有GPS和网络内容

import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import com.app.callbacks.OnLocationDetectectionListener;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.provider.Settings;
import android.util.Log;
import android.widget.Toast;

public class MyLocationManager {
    /** The minimum distance to GPS change Updates in meters **/
    private final long MIN_DISTANCE_CHANGE_FOR_UPDATES_FOR_GPS = 2; // 2
                                                                    // meters
    /** The minimum time between GPS updates in milliseconds **/
    private final long MIN_TIME_BW_UPDATES_OF_GPS = 1000 * 5 * 1; // 5
                                                                    // seconds

    /** The minimum distance to NETWORK change Updates in meters **/
    private final long MIN_DISTANCE_CHANGE_FOR_UPDATES_FOR_NETWORK = 5; // 5
                                                                        // meters
    /** The minimum time between NETWORK updates in milliseconds **/
    private final long MIN_TIME_BW_UPDATES_OF_NETWORK = 1000 * 10 * 1; // 10
                                                                        // seconds

    /**
     * Lets just say i don't trust the first location that the is found. This is
     * to avoid that
     **/

    private int NetworkLocationCount = 0, GPSLocationCount = 0;
    private boolean isGPSEnabled;
    private boolean isNetworkEnabled;
    /**
     * Don't do anything if location is being updated by Network or by GPS
     */
    private boolean isLocationManagerBusy;
    private LocationManager locationManager;
    private Location currentLocation;
    private Context mContext;
    private OnLocationDetectectionListener mListener;

    public MyLocationManager(Context mContext,
            OnLocationDetectectionListener mListener) {
        this.mContext = mContext;
        this.mListener = mListener;
    }

    /**
     * Start the location manager to find my location
     */
    public void startLocating() {
        try {
            locationManager = (LocationManager) mContext
                    .getSystemService(Context.LOCATION_SERVICE);

            // Getting GPS status
            isGPSEnabled = locationManager
                    .isProviderEnabled(LocationManager.GPS_PROVIDER);

            // Getting network status
            isNetworkEnabled = locationManager
                    .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

            if (!isGPSEnabled && !isNetworkEnabled) {
                // No network provider is enabled
                showSettingsAlertDialog();
            } else {
                // If GPS enabled, get latitude/longitude using GPS Services
                if (isGPSEnabled) {
                    locationManager.requestLocationUpdates(
                            LocationManager.GPS_PROVIDER,
                            MIN_TIME_BW_UPDATES_OF_GPS,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES_FOR_GPS,
                            gpsLocationListener);

                }
                if (isNetworkEnabled) {
                    locationManager.requestLocationUpdates(
                            LocationManager.NETWORK_PROVIDER,
                            MIN_TIME_BW_UPDATES_OF_NETWORK,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES_FOR_NETWORK,
                            networkLocationListener);

                }
            }
            /**
             * My 30 seconds plan to get myself a location
             */
            ScheduledExecutorService se = Executors
                    .newSingleThreadScheduledExecutor();
            se.schedule(new Runnable() {

                @Override
                public void run() {
                    if (currentLocation == null) {
                        if (isGPSEnabled) {
                            currentLocation = locationManager
                                    .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        } else if (isNetworkEnabled) {
                            currentLocation = locationManager
                                    .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

                        }
                        if (currentLocation != null && mListener != null) {
                            locationManager.removeUpdates(gpsLocationListener);
                            locationManager
                                    .removeUpdates(networkLocationListener);
                            mListener.onLocationDetected(currentLocation);
                        }
                    }
                }
            }, 30, TimeUnit.SECONDS);

        } catch (Exception e) {
            Log.e("Error Fetching Location", e.getMessage());
            Toast.makeText(mContext,
                    "Error Fetching Location" + e.getMessage(),
                    Toast.LENGTH_SHORT).show();
        }
    }

    /**
     * Handle GPS location listener callbacks
     */
    private LocationListener gpsLocationListener = new LocationListener() {

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onProviderEnabled(String provider) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onProviderDisabled(String provider) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onLocationChanged(Location location) {

            if (GPSLocationCount != 0 && !isLocationManagerBusy) {
                Log.d("GPS Enabled", "GPS Enabled");
                isLocationManagerBusy = true;
                currentLocation = location;
                locationManager.removeUpdates(gpsLocationListener);
                locationManager.removeUpdates(networkLocationListener);
                isLocationManagerBusy = false;
                if (currentLocation != null && mListener != null) {
                    mListener.onLocationDetected(currentLocation);
                }
            }
            GPSLocationCount++;
        }
    };
    /**
     * Handle Network location listener callbacks
     */
    private LocationListener networkLocationListener = new LocationListener() {

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onProviderEnabled(String provider) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onProviderDisabled(String provider) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onLocationChanged(Location location) {
            if (NetworkLocationCount != 0 && !isLocationManagerBusy) {
                Log.d("Network", "Network");
                isLocationManagerBusy = true;
                currentLocation = location;
                locationManager.removeUpdates(gpsLocationListener);
                locationManager.removeUpdates(networkLocationListener);
                isLocationManagerBusy = false;
                if (currentLocation != null && mListener != null) {
                    mListener.onLocationDetected(currentLocation);
                }
            }
            NetworkLocationCount++;
        }
    };

    /**
     * Function to show settings alert dialog. On pressing the Settings button
     * it will launch Settings Options.
     * */
    public void showSettingsAlertDialog() {
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

        // Setting Dialog Title
        alertDialog.setTitle("GPS is settings");

        // Setting Dialog Message
        alertDialog
                .setMessage("GPS is not enabled. Do you want to go to settings menu?");

        // On pressing the Settings button.
        alertDialog.setPositiveButton("Settings",
                new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Intent intent = new Intent(
                                Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                        mContext.startActivity(intent);
                    }
                });

        // On pressing the cancel button
        alertDialog.setNegativeButton("Cancel",
                new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });

        // Showing Alert Message
        alertDialog.show();
    }
}

2.我创建了一个接口(回调)OnLocationDetectionListener.java,以便将结果传递回调用片段或活动

import android.location.Location;

public interface OnLocationDetectectionListener {
    public void onLocationDetected(Location mLocation);
}

3.然后我制作了一个MainAppActivty.java Activity,它实现了OnLocationDetectionListener接口,下面是我如何在其中接收位置

public class MainAppActivty extends Activity implements
        OnLocationDetectectionListener {

    private Location currentLocation;
    private MyLocationManager mLocationManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        setContentView(R.layout.activity_home);
        super.onCreate(savedInstanceState);
            mLocationManager = new MyLocationManager(this, this);
            mLocationManager.startLocating();
    }

    @Override
    public void onLocationDetected(Location mLocation) {
        //Your new Location is received here
        currentLocation = mLocation;
    }

4.将以下权限添加到清单文件

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

希望这对其他人有帮助:)

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

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

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。