Codename one GPS tracker

Question

我想用GPS信號跟蹤設備。同時顯示緯度，經度，高度和速度。

我用這個代碼並且在屏幕上沒有任何結果：

@Override 
protected void onGpsTracker_ButtonAction(Component c, ActionEvent event) { 
    try { 
     int i = 0; 
     Location loc = mylocLocationManager.getCurrentLocation(); 
     if(loc.getStatus()==LocationManager.AVAILABLE) { 
     } else { 
      Dialog.show("Error!", "Falla de señal", "OK", null); 
     } 
     mylocLocationManager.setLocationListener(new LocationListener() { 
      public void locationUpdated(Location location) { 
       gpsLocation= location; 
       Component c = null; 
       Label labelalt = (Label)findByName("altitudT", c); 
       Label labellat = (Label)findByName("latitudT", c); 
       Label labellng = (Label)findByName("longitudT", c); 
       Label labeldist = (Label)findByName("distanciaT", c); 
       Label labelspeed = (Label)findByName("speedT", c); 
       altmax= location.getAltitude(); 
       double lat = location.getLatitude(); 
       double lng = location.getLongitude(); 
       float speed = location.getVelocity(); 

       double alt = location.getAltitude(); 
       velprompos = velprompos + 1; 
       totspeed = (int) (totspeed + speed); 
       velopro = totspeed/velprompos; 
       totalt = altmax - alt; 

       velmax=speed; 
       Coord lastLocation = new Coord(lat, lng); 
       mapComponent.zoomTo(lastLocation, 15); 

       prevdistance = totdistance; 
       prevLon = currentLon; 
       prevLat = currentLat; 
       String Salt = String.valueOf(alt); 
       labelalt.setText(Salt); 
       String Slat = String.valueOf(lat); 
       labellat.setText(Slat); 
       String Slng = String.valueOf(lng); 
       labellng.setText(Slng); 
       String Sspeed = String.valueOf(speed); 
       labelspeed.setText(Sspeed); 

       //aca hay q pner dibujo lineas 
      } 

      public void providerStateChanged(int newState) { 
       //positionMethod(); 
      } 
     }); 
    } catch (Exception ex) { 
     ex.printStackTrace(); 
     gpsLocation = null; 
    } 
}  

的想法是讓當設備被移動的位置，並顯示這導致一些標籤。任何幫助？

Answer 1

您正在錯誤地實施一些事情。

1. 添加@override到被覆蓋的方法，如locationUpdated和providerStateChanged。

2. 不要重新申報Component c爲，並將其設置爲null

3. 直接與find方法調用它們讓你的標籤，並通過c作爲參數

4. revalidate或repaint表單後每次更新。

5. 作爲一般的建議，讓您的變量聲明一致，聲明芒果數爲numOfMangoes和不numberofmangoes也不numofmangoes也不Numberofmangoes。

   @Override 
   protected void onGpsTracker_ButtonAction(Component c, ActionEvent event) { 
       try { 
        int i = 0; 
        Location loc = mylocLocationManager.getCurrentLocation(); 
        if (loc.getStatus() == LocationManager.AVAILABLE) { 
         System.out.println("Location available"); 
        } else { 
         Dialog.show("Error!", "Falla de señal", "OK", null); 
        } 
        final LocationManager mylocLocationManager = LocationManager.getLocationManager(); 
        mylocLocationManager.setLocationListener(new LocationListener() { 
         @Override 
         public void locationUpdated(Location location) { 
          gpsLocation = location; 
          Label labelspeed = ; 
          altmax = location.getAltitude(); 
          double lat = location.getLatitude(); 
          double lng = location.getLongitude(); 
          float speed = location.getVelocity(); 
   
          double alt = location.getAltitude(); 
          velprompos = velprompos + 1; 
          totspeed = (int) (totspeed + speed); 
          velopro = totspeed/velprompos; 
          totalt = altmax - alt; 
   
          velmax = speed; 
          Coord lastLocation = new Coord(lat, lng); 
          mapComponent.zoomTo(lastLocation, 15); 
   
          prevdistance = totdistance; 
          prevLon = currentLon; 
          prevLat = currentLat; 
          String Salt = String.valueOf(alt); 
          findAltitudT(c).setText(Salt); 
          String Slat = String.valueOf(lat); 
          findLatitudT(c).setText(Slat); 
          String Slng = String.valueOf(lng); 
          findLongitudT(c).setText(Slng); 
          String Sspeed = String.valueOf(speed); 
          findSpeedT(c).setText(Sspeed); 
   
          c.getComponentForm().revalidate(); 
          //aca hay q pner dibujo lineas 
         } 
   
         @Override 
         public void providerStateChanged(int newState) { 
          //positionMethod(); 
         } 
        }); 
   
       } catch (Exception ex) { 
        ex.printStackTrace(); 
        gpsLocation = null; 
       } 
   }