Question

在我的应用中，我需要用户当前位置的纬度和经度值。最初我检查GPS坐标是否可用，如果不可用，我将使用网络提供商获取用户位置的这些拉特隆值，因为取得GPS坐标是耗时的。一旦GPS co ordiantes可用，我需要获得这些值。谷歌搜索大约2天我发现了一些有关该问题的信息，并设法构建了一些代码，如下所示。我被困住了，无法前进。

我的活动

public class MainActivity extends Activity {

    double x, y;

    Timer timer;
    LocationManager lm;
    boolean gps_enabled = false;
    boolean network_enabled = false;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        lm = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);

        gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
        network_enabled = lm
                .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        if (!gps_enabled && !network_enabled) {
            Context context = getApplicationContext();
            int duration = Toast.LENGTH_SHORT;
            Toast toast = Toast.makeText(context, "nothing is enabled",
                    duration);
            toast.show();

        }

        if (gps_enabled)
            lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0,
                    locationListenerGps);
        if (network_enabled)
            lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0,
                    locationListenerNetwork);
        timer = new Timer();
        timer.schedule(new GetLastLocation(), 20000);

    }

    LocationListener locationListenerGps = new LocationListener() {
        public void onLocationChanged(Location location) {
            timer.cancel();
            x = location.getLatitude();
            y = location.getLongitude();
            lm.removeUpdates(this);
            lm.removeUpdates(locationListenerNetwork);

            Context context = getApplicationContext();
            int duration = Toast.LENGTH_SHORT;
            Toast toast = Toast.makeText(context,
                    "gps enabled " + x + "\n" + y, duration);
            toast.show();
        }

        public void onProviderDisabled(String provider) {
        }

        public void onProviderEnabled(String provider) {
        }

        public void onStatusChanged(String provider, int status, Bundle extras) {
        }
    };

    LocationListener locationListenerNetwork = new LocationListener() {
        public void onLocationChanged(Location location) {
            timer.cancel();
            x = location.getLatitude();
            y = location.getLongitude();
            lm.removeUpdates(this);
            lm.removeUpdates(locationListenerGps);

            Context context = getApplicationContext();
            int duration = Toast.LENGTH_SHORT;
            Toast toast = Toast.makeText(context, "network enabled" + x + "\n"
                    + y, duration);
            toast.show();
        }

        public void onProviderDisabled(String provider) {
        }

        public void onProviderEnabled(String provider) {
        }

        public void onStatusChanged(String provider, int status, Bundle extras) {
        }
    };

    class GetLastLocation extends TimerTask {
        @Override
        public void run() {
            lm.removeUpdates(locationListenerGps);
            lm.removeUpdates(locationListenerNetwork);

            Location net_loc = null, gps_loc = null;
            if (gps_enabled)
                gps_loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
            if (network_enabled)
                net_loc = lm
                        .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

            // if there are both values use the latest one
            if (gps_loc != null && net_loc != null) {
                if (gps_loc.getTime() > net_loc.getTime()) {
                    x = gps_loc.getLatitude();
                    y = gps_loc.getLongitude();
                    Context context = getApplicationContext();
                    int duration = Toast.LENGTH_SHORT;
                    Toast toast = Toast.makeText(context, "gps lastknown " + x
                            + "\n" + y, duration);
                    toast.show();
                } else {
                    x = net_loc.getLatitude();
                    y = net_loc.getLongitude();
                    Context context = getApplicationContext();
                    int duration = Toast.LENGTH_SHORT;
                    Toast toast = Toast.makeText(context, "network lastknown "
                            + x + "\n" + y, duration);
                    toast.show();

                }

            }

            if (gps_loc != null) {
                {
                    x = gps_loc.getLatitude();
                    y = gps_loc.getLongitude();
                    Context context = getApplicationContext();
                    int duration = Toast.LENGTH_SHORT;
                    Toast toast = Toast.makeText(context, "gps lastknown " + x
                            + "\n" + y, duration);
                    toast.show();
                }

            }
            if (net_loc != null) {
                {
                    x = net_loc.getLatitude();
                    y = net_loc.getLongitude();
                    Context context = getApplicationContext();
                    int duration = Toast.LENGTH_SHORT;
                    Toast toast = Toast.makeText(context, "network lastknown "
                            + x + "\n" + y, duration);
                    toast.show();

                }
            }
            Context context = getApplicationContext();
            int duration = Toast.LENGTH_SHORT;
            Toast toast = Toast.makeText(context, "no last know avilable",
                    duration);
            toast.show();

        }
    }
}

到目前为止，使用上面的代码我从网络提供商那里获得了lat lon值，但无法获得GPS坐标。我应该在上面的代码中添加或编辑什么来获取GPS坐标？

Answer 1

我发现Android开发人员指南非常有用：http://developer.android.com/guide/topics/location/strategies.html#BestEstimate

它说明了典型的程序流程应该如何使用不同的位置提供程序来获得最准确的用户位置。

Android最初使用网络提供商获取经度和经度，之后使用GPS获取

1 个答案: