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Activity Class中创建自定义方法:

private void getTheUserPermission() {
        ActivityCompat.requestPermissions(this, new String[]
                {Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION);
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        LocationGetter locationGetter = new LocationGetter(FreshMenuSearchActivity.this, REQUEST_LOCATION, locationManager);


        if (!locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {

            locationGetter.OnGPS();
        } else {

            locationGetter.getLocation();
        }
    }

生成用户定义的类名LocationGetter:-

public class LocationGetter {

        private int REQUEST_LOCATION;
        private FreshMenuSearchActivity mContext;
        private LocationManager locationManager;
        private Geocoder geocoder;

        public LocationGetter(FreshMenuSearchActivity mContext, int requestLocation, LocationManager locationManager) {
            this.mContext = mContext;
            this.locationManager = locationManager;
            this.REQUEST_LOCATION = requestLocation;
        }


        public void getLocation() {

            if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext,

                    Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(mContext, new String[]
                        {Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION);
            } else {
                Location LocationGps = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                Location LocationNetwork = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                Location LocationPassive = locationManager.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);

                if (LocationGps != null) {
                    double lat = LocationGps.getLatitude();
                    double longi = LocationGps.getLongitude();
                    getTheAddress(lat, longi);
                } else if (LocationNetwork != null) {
                    double lat = LocationNetwork.getLatitude();
                    double longi = LocationNetwork.getLongitude();
                    getTheAddress(lat, longi);
                } else if (LocationPassive != null) {
                    double lat = LocationPassive.getLatitude();
                    double longi = LocationPassive.getLongitude();
                    getTheAddress(lat, longi);
                } else {
                    Toast.makeText(mContext, "Can't Get Your Location", Toast.LENGTH_SHORT).show();
                }

            }

        }

        private void getTheAddress(double latitude, double longitude) {
            List<Address> addresses;
            geocoder = new Geocoder(mContext, Locale.getDefault());

            try {
                addresses = geocoder.getFromLocation(latitude, longitude, 1);
                String address = addresses.get(0).getAddressLine(0);
                String city = addresses.get(0).getLocality();
                String state = addresses.get(0).getAdminArea();
                String country = addresses.get(0).getCountryName();
                String postalCode = addresses.get(0).getPostalCode();
                String knownName = addresses.get(0).getFeatureName();
                Log.d("neel", address);
            } catch (IOException e) {
                e.printStackTrace();
            }


        }

        public void OnGPS() {

            final AlertDialog.Builder builder = new AlertDialog.Builder(mContext);

            builder.setMessage("Enable GPS").setCancelable(false).setPositiveButton("YES", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    mContext.startActivity(new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS));
                }
            }).setNegativeButton("NO", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {

                    dialog.cancel();
                }
            });
            final AlertDialog alertDialog = builder.create();
            alertDialog.show();
        }

    }

其他回答

在Activity Class中创建自定义方法:

private void getTheUserPermission() {
        ActivityCompat.requestPermissions(this, new String[]
                {Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION);
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        LocationGetter locationGetter = new LocationGetter(FreshMenuSearchActivity.this, REQUEST_LOCATION, locationManager);


        if (!locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {

            locationGetter.OnGPS();
        } else {

            locationGetter.getLocation();
        }
    }

生成用户定义的类名LocationGetter:-

public class LocationGetter {

        private int REQUEST_LOCATION;
        private FreshMenuSearchActivity mContext;
        private LocationManager locationManager;
        private Geocoder geocoder;

        public LocationGetter(FreshMenuSearchActivity mContext, int requestLocation, LocationManager locationManager) {
            this.mContext = mContext;
            this.locationManager = locationManager;
            this.REQUEST_LOCATION = requestLocation;
        }


        public void getLocation() {

            if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext,

                    Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(mContext, new String[]
                        {Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION);
            } else {
                Location LocationGps = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                Location LocationNetwork = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                Location LocationPassive = locationManager.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);

                if (LocationGps != null) {
                    double lat = LocationGps.getLatitude();
                    double longi = LocationGps.getLongitude();
                    getTheAddress(lat, longi);
                } else if (LocationNetwork != null) {
                    double lat = LocationNetwork.getLatitude();
                    double longi = LocationNetwork.getLongitude();
                    getTheAddress(lat, longi);
                } else if (LocationPassive != null) {
                    double lat = LocationPassive.getLatitude();
                    double longi = LocationPassive.getLongitude();
                    getTheAddress(lat, longi);
                } else {
                    Toast.makeText(mContext, "Can't Get Your Location", Toast.LENGTH_SHORT).show();
                }

            }

        }

        private void getTheAddress(double latitude, double longitude) {
            List<Address> addresses;
            geocoder = new Geocoder(mContext, Locale.getDefault());

            try {
                addresses = geocoder.getFromLocation(latitude, longitude, 1);
                String address = addresses.get(0).getAddressLine(0);
                String city = addresses.get(0).getLocality();
                String state = addresses.get(0).getAdminArea();
                String country = addresses.get(0).getCountryName();
                String postalCode = addresses.get(0).getPostalCode();
                String knownName = addresses.get(0).getFeatureName();
                Log.d("neel", address);
            } catch (IOException e) {
                e.printStackTrace();
            }


        }

        public void OnGPS() {

            final AlertDialog.Builder builder = new AlertDialog.Builder(mContext);

            builder.setMessage("Enable GPS").setCancelable(false).setPositiveButton("YES", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    mContext.startActivity(new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS));
                }
            }).setNegativeButton("NO", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {

                    dialog.cancel();
                }
            });
            final AlertDialog alertDialog = builder.create();
            alertDialog.show();
        }

    }
public static Location getBestLocation(Context ctxt) {
    Location gpslocation = getLocationByProvider(
        LocationManager.GPS_PROVIDER, ctxt);
    Location networkLocation = getLocationByProvider(
        LocationManager.NETWORK_PROVIDER, ctxt);
    Location fetchedlocation = null;
    // if we have only one location available, the choice is easy
    if (gpslocation != null) {
        Log.i("New Location Receiver", "GPS Location available.");
        fetchedlocation = gpslocation;
    } else {
        Log.i("New Location Receiver",
            "No GPS Location available. Fetching Network location lat="
                + networkLocation.getLatitude() + " lon ="
                + networkLocation.getLongitude());
        fetchedlocation = networkLocation;
    }
    return fetchedlocation;
}

/**
 * get the last known location from a specific provider (network/gps)
 */
private static Location getLocationByProvider(String provider, Context ctxt) {
    Location location = null;
    // if (!isProviderSupported(provider)) {
    // return null;
    // }
    LocationManager locationManager = (LocationManager) ctxt
            .getSystemService(Context.LOCATION_SERVICE);
    try {
        if (locationManager.isProviderEnabled(provider)) {
            location = locationManager.getLastKnownLocation(provider);
        }
    } catch (IllegalArgumentException e) {
        Log.i("New Location Receiver", "Cannot access Provider " + provider);
    }
    return location;
}

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

我不确定基于位置的服务是否可以从GPS以外的其他基础设施获取位置,但根据那篇文章,这似乎是可能的:

应用程序可以调用几种类型的定位方法。使用移动电话网络:当前单元格ID可用于识别基站收发信机(BTS)设备正在通信以及该BTS的位置。显然,这种方法的准确性取决于单元格的大小,以及可能非常不准确。GSM蜂窝可以是2到20直径千米。另外与细胞ID一起使用的技术可以精度在150米以内。使用卫星:全球定位系统(GPS),受控美国国防部使用由24颗卫星组成的星座围绕地球运行。GPS确定通过计算设备的位置时间差信号来自不同的卫星到达接受者GPS信号是编码的,所以移动设备必须配备使用GPS接收器。GPS是可能是最准确的方法(如果GPS接收机具有清晰的天空视图),但它也有一些缺点:硬件可能很昂贵电池使用时,需要冷启动后的热身对可见卫星的初步定位。它还受到“峡谷效应”的影响在城市,卫星能见度是间歇性的。使用短程定位信标:相对小面积,如单个建筑,局域网可以提供其他位置服务。例如,适当地配备的设备可以使用蓝牙短程定位。

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" />