如何获取Android中位置管理器的上一个已知位置？

Question

我使用简单的位置管理对象来获取lastKnownLocation()装置,但得到的空对象在返回任何一个可以告诉我为什么？

代码:

public Location getLocation() {
    LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);        
    if (locationManager != null) {          
        Location lastKnownLocationGPS = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        if (lastKnownLocationGPS != null) {             
            return lastKnownLocationGPS;
        } else {                
            Location loc =  locationManager.getLastKnownLocation(LocationManager.PASSIVE_PROVIDER);
            System.out.println("1::"+loc);----getting null over here
            System.out.println("2::"+loc.getLatitude());
            return loc;
        }
    } else {            
        return null;
    }
}
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.location);
    getLocation();-----calling service

 }

权限给出:

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

所以缺少什么设置？我已经检查了我的位置服务在设备中,请提供一些工作示例的链接

Answer 1

在获取最后一个位置之前，也许您想获取当前位置，检查是否为空或有。如果没有设置最后一个位置，如果你想使用FusedLocationProviderClient 并且在使用它之前添加这个：

实现 'com.google.android.gms:play-services-location:16.0.0'

在您的 build.gradle(Module: app) 上，并在活动创建时调用方法 zoomMyCuurentLocation()。

private void zoomMyCuurentLocation() {
    LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
    Criteria criteria = new Criteria();
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION);
    }
    Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
    if (location != null) {
        double lat = location.getLatitude();
        double longi = location.getLongitude();
        LatLng latLng = new LatLng(lat,longi);
        mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 14.f));
        Log.d(TAG, "zoomMyCuurentLocation: location not null");
    } else {
        setMyLastLocation();
    }
}

private void setMyLastLocation() {
    Log.d(TAG, "setMyLastLocation: excecute, and get last location");
    FusedLocationProviderClient fusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        return;
    }
    fusedLocationClient.getLastLocation().addOnSuccessListener(this, new OnSuccessListener<Location>() {
        @Override
        public void onSuccess(Location location) {
            if (location != null){
                double lat = location.getLatitude();
                double longi = location.getLongitude();
                LatLng latLng = new LatLng(lat,longi);
                Log.d(TAG, "MyLastLocation coordinat :"+latLng);
                mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 14.f));
            }
        }
    });
}

Answer 2

愚蠢的事情作为答案...我重新启动了我的设备...并且它起作用了...请确保您的位置服务已启用并正常工作