Android在用户在地图上移动时绘制路线

Question

我正在尝试绘制一条路线，因为用户使用GPS移动但出现了问题，并且没有显示该行。我不确定问题是什么。 任何人都可以向我指出我做了什么错误。 提前致谢

public class MainActivity extends FragmentActivity implements OnMyLocationChangeListener, OnMapClickListener, OnMapLongClickListener {

    GoogleMap g1;
    private double longitude = -1;
    private double latitude = -1;
    private double lastLocationTime = 0;
    Polyline line, distance;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);        
        SupportMapFragment sf1 = (SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map); 
        g1 = sf1.getMap(); 
        g1.setMapType(GoogleMap.MAP_TYPE_NORMAL);
        g1.setMyLocationEnabled(true);
        g1.setOnMapClickListener(this);
        g1.setOnMapLongClickListener( this);
        g1.setOnMyLocationChangeListener(this);        
        distance = line;     
    }
    @Override
    public void onMapClick(LatLng arg0) { }     
    @Override
    public void onMapLongClick(LatLng arg0) {}
    @Override
    public void onMyLocationChange(Location location) {
   TextView Location = (TextView) findViewById(R.id.textView1);
     double oldlat = latitude;
        double oldlong = longitude;
      latitude = calcLatitude(location, latitude);
      longitude = calcLongitude(location, longitude);
Location.setText("Latitude:" +  latitude  + ", Longitude:"+ longitude );
line = g1.addPolyline(new PolylineOptions().add(new LatLng(oldlat, oldlong), new LatLng(latitude, longitude)).width(5).color(Color.RED));}

private double calcLongitude(Location location, double oldlongitude) {
       double newlongitude = oldlongitude;
    if(oldlongitude == -1)
    {oldlongitude = newlongitude;}
    if(location.getAccuracy() <= 30)
       {
        newlongitude = (2 * oldlongitude + location.getLatitude())  / (2 + 1);
     lastLocationTime = System.currentTimeMillis();
    }
    if (lastLocationTime >= 2) {
     newlongitude = location.getLatitude();
     }
    return newlongitude;    
    }
    private double calcLatitude(Location location, double oldlatitude) {        double newlatitude = oldlatitude;
        if(oldlatitude == -1){
    oldlatitude = newlatitude; }
        if(location.getAccuracy() <= 30){ 
       newlatitude = (2 * oldlatitude + location.getLatitude()) / (2 + 1);
            lastLocationTime = System.currentTimeMillis();
        }
    if (lastLocationTime >= 2) {
            newlatitude = location.getLatitude();
        }
        return newlatitude;
       }
  }