1

デバイスが衛星からデータを取得しているかどうかを確認したいと思います。現在地を取得したら、何かをします。それ以外の場合、まだ座標を取得していない場合は、メッセージをトーストしたいと思います。すでに座標を持っているかどうかはどうすればわかりますか？

GeoPoint h = null;
double latitude = 10, longitude = 10;
public void onClick(View v) 
{
    switch (v.getId())
    {
      case R.id.get_GPS:
          final LocationManager manager = (LocationManager) getSystemService( Context.LOCATION_SERVICE );
          if(isInternetOn() && manager.isProviderEnabled(LocationManager.GPS_PROVIDER))
          {
//I want here to check, if I get latitude and longitude values, which differ from 10 x 10, I go to my map, otherwise I say, that there's no information received from satellite.
/*
              h = new GeoPoint((int) (latitude * 1000000), (int) (longitude * 1000000));

              if(h.getLatitudeE6()==h.getLongitudeE6() && h.getLongitudeE6()==10000000)
              {
                  Toast.makeText(this, "No information received from satellite yet.", Toast.LENGTH_LONG).show();
                  break;
              }
              */
              Intent i = new Intent (this,getGPS.class);
              startActivity(i);
          }
          else
          {   
              if(!isInternetOn() && !manager.isProviderEnabled( LocationManager.GPS_PROVIDER))
              {
                  buildAlertMessageNoGpsNoInternet();
                  break;
              }

              if(!isInternetOn())
              {
                  buildAlertMessageNoInternet();
                  break;
              }
              if(!manager.isProviderEnabled( LocationManager.GPS_PROVIDER))
              {
                  buildAlertMessageNoGps();
                  break;
              }
          }

        break;
      case R.id.about_button:
        Intent j = new Intent(this, About.class);
        startActivity(j);
        break;
      case R.id.exit_button:
        this.moveTaskToBack(true);
        break;
    }
}

サム、「if」でNullPointerExceptionが発生します。

if(manager.isProviderEnabled(LocationManager.GPS_PROVIDER))
          {

              Location location = manager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

              /*Here ->*/if(location.getTime() > ((Calendar.getInstance().getTimeInMillis()) - 10000))
              {
                  Intent i = new Intent (this, getGPS.class);
                  startActivity(i);
              }

              else 
              {
                    // Wait for new location
                    LocationListener locationListener = new myLocationListener();
                    manager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0,locationListener);
              }
}

Logcat

05-05 11：42：49.444：E / AndroidRuntime（300）：java.lang.NullPointerException

4

1 に答える 1

1

私はこれに沿って何かを試みます：

public class Example extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        LocationManager manager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        Location location = manager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

        if(location.getTime() > Calendar.getInstance().getTimeInMillis() - 2 * 60 * 1000) {
            // Do something with the recent location fix
        }
        else {
            // Wait for new location
            LocationListener locationListener = new myLocationListener();
            manager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0,locationListener);
        }
    }

    private class myLocationListener implements LocationListener {
        public void onLocationChanged(Location location) {
            if (location != null) {
                Log.v("Location Changed", location.getLatitude() + " " + location.getLongitude());
                // Do something with current location
            }
        }

        // Must implement missing functions!
    }
}

添加

ここで場所がnullの場合、それはおそらく何らかの理由で最後の既知の場所がないことを意味します。簡単な修正：

if(location != null && location.getTime() > ((Calendar.getInstance().getTimeInMillis()) - 10000))
于 2012-05-03T20:14:37.833 に答える