Android - Google地图为位置返回null [重复]

Posted 2021-03-28

这个问题在这里已有答案：

• getLastKnownLocation() returns null [closed] 1回答

我需要在日志中看到我的位置，频率为0.1秒。

mMap.setMyLocationEnabled(true);
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
final Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
        for (int i = 1; i < 100; i++)
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    if (ActivityCompat.checkSelfPermission(MapsActivity.this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(MapsActivity.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;
                    }
                    mMap.setMyLocationEnabled(true);
                    LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
                    Criteria criteria = new Criteria();
                    final Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
                    Log.d("Coordinates: ",location.getLongitude() + "," + location.getLatitude());
                }
            }, 100 * i);

我通过模拟器看到日志中的坐标，但是当我通过USB连接手机时，我遇到了Log.d()线路崩溃，出现以下错误：

java.lang.NullPointerException: Attempt to invoke virtual method 'double android.location.Location.getLongitude()' on a null object reference

答案

当找不到先前记录的位置或者找到之前的位置是很久以前并且它的gps数据到期时，最后一个已知位置可以为空。

如果找到的最后一个位置为null，则可以使用融合位置提供程序API并查找位置。你将在onLocationChanged回调中获取它。