Java 获取Android中的最后一个位置

我按照本教程检索设备的位置，但它不起作用

当我这样做时：

mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

“mLastLocation”为空，为什么

编辑

我试着在尼鲁的安萨雷那样做：

public Location setLocation()
    {
        Location location;
        final int MIN_TIME_BW_UPDATES = 300;
        final int MIN_DISTANCE_CHANGE_FOR_UPDATES = 50;
        Criteria criteria = new Criteria();
        criteria.setAccuracy(Criteria.ACCURACY_FINE);
        criteria.setAltitudeRequired(false);
        criteria.setBearingRequired(false);
        criteria.setCostAllowed(true);
        criteria.setPowerRequirement(Criteria.POWER_LOW);

        locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

        String bestProvider = locationManager.getBestProvider(criteria, true);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
        {
            if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {}
        }

        location = locationManager.getLastKnownLocation(bestProvider);

        localStorage.putFloat("latitude", (float) location.getLatitude());
        localStorage.putFloat("longitude", (float) location.getLongitude());
        localStorage.commit();

        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, (LocationListener) this);



        return location;
    }

    @Override
    public void onLocationChanged(Location location)
    {
        localStorage.putFloat("latitude", (float) location.getLatitude());
        localStorage.putFloat("longitude", (float) location.getLongitude());
        localStorage.commit();
    }

---

但是“location”为空，为什么？

getLastKnownLocation（）返回最后一个已知位置…重新安装应用程序后，它将没有任何最后一个已知位置…因此将导致NPE…而使用下面的代码

public Location getLocation() {
    try {
        locationManager = (LocationManager) mContext
                .getSystemService(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
        } else {
            this.canGetLocation = true;
            if (isNetworkEnabled) {
                locationManager.requestLocationUpdates(
                        LocationManager.NETWORK_PROVIDER,
                        MIN_TIME_BW_UPDATES,
                        MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                Log.d("Network", "Network Enabled");
                if (locationManager != null) {
                    location = locationManager
                            .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                    if (location != null) {
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                    }
                }
            }
            // if GPS Enabled get lat/long using GPS Services
            if (isGPSEnabled) {
                if (location == null) {
                    locationManager.requestLocationUpdates(
                            LocationManager.GPS_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    Log.d("GPS", "GPS Enabled");
                    if (locationManager != null) {
                        location = locationManager
                                .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        if (location != null) {
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
                        }
                    }
                }
            }
        }

    } catch (Exception e) {
        e.printStackTrace();
    }

    return location;

---

您可以尝试以下代码段：

public class LocationProvider
{
    private static final String     TAG         = "DEBUG";
    private static final String[]   provider    = new String[]
                                                {
            LocationManager.GPS_PROVIDER,
            LocationManager.NETWORK_PROVIDER,
            LocationManager.PASSIVE_PROVIDER
                                                };

    public Location getLocationByProvider(Context context)
    {
        Location location = null;
        // LocationManager locationManager = (LocationManager) context.getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
        LocationManager locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
        try
        {
            for (int i = 0; i < provider.length; i++)
            {
                if (locationManager.isProviderEnabled(provider[i]))
                {
                    // locationManager.requestLocationUpdates(provider[i], 0, 0, locationListenerGps);
                    location = locationManager.getLastKnownLocation(provider[i]);
                    if (location != null)
                    {
                        break;
                    }
                }
            }
        }
        catch (IllegalArgumentException e)
        {
            Log.d(TAG, "Cannot acces Provider " + provider);
        }
        return location;
    }

}

---

希望这对您有所帮助。：-）

文档本身说，当位置不可用时，getLastLocation可能返回null。 如果为null，则在OnConnected（）方法中调用requestLocationUpdate方法，如下所示：

@Override
public void onConnected(Bundle connectionHint) {
    mCurrentLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
    if (mCurrentLocation == null) {
        LocationServices.FusedLocationApi.requestLocationUpdates(
            mGoogleApiClient, mLocationRequest, this);
    }
}

在调用RequestLocationUpdate之前，请创建mLocationRequest对象：

mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(10000);   
mLocationRequest.setFastestInterval(5000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);

当位置可用时，OnLocationChanged将自动触发。获取此回调的速率由创建请求对象时放入setInterval（）的时间间隔定义

@Override
public void onLocationChanged(Location location) {
    mCurrentLocation = location;        
}

然后将更新您的位置对象

---

请点击此链接：

多亏了这篇文章，我解决了类似的问题：

事实上，如果您使用

compileSdkVersion 23

（或更高版本），如果您希望应用程序在android 6.0+设备上正确运行，您必须处理新的android权限系统。。。更多信息可在此处找到：

测试应用程序的一个快速而肮脏的解决方法是将build.gradle中的

compileSdkVersion

和

targetSdkVersion

更改为22

---

然而，我认为这是愚蠢的，没有明确的错误信息，但只有一个空…

可能重复相同的问题，在安卓6.0上的Nexus 6p和安卓6.0.1上的Nexus 5，但它在5.1.1上的Nexus 4上运行良好，所以可能是平台问题。。。你使用哪个版本的Android？冷静，祝你有一个愉快的一天：-）

@Override
public void onLocationChanged(Location location) {
    mCurrentLocation = location;        
}