pegar e legar um item

não estou a conseguir por a funcionar o pegar e lagar

segue-se o codigo

package mygame.menus;

import org.slf4j.*;

import com.jme3.app.Application;
import com.jme3.app.state.BaseAppState;
import com.jme3.math.*;
import com.jme3.scene.*;

import com.simsilica.lemur.*;
import com.simsilica.lemur.component.QuadBackgroundComponent;

import com.simsilica.lemur.grid.ArrayGridModel;
import com.simsilica.lemur.input.InputMapper;
import com.simsilica.lemur.style.ElementId;
import mygame.Main;
import mygame.MainGameFunctions;
import mygame.MainMenuState;
import mygame.panels.CustomGridPanel;

/**
*
*
* @author Pedro Alves
*/
public class InventoryMenuState extends BaseAppState {

 static Logger log = LoggerFactory.getLogger(InventoryMenuState.class);

 private Container mainWindow;

 //private Container sessionButtons;
 public InventoryMenuState(boolean enabled) {
 setEnabled(enabled);

 }

 /**
 * Returns the tabbed panel used in the in-game menu. This lets other states
 * potentially add their own in-game menu tabs.
 *
 * @return
 */
 /* public TabbedPanel getTabs() {
 return tabs;
 }

 public List<Action> getSessionActions() {
 return sessionActions;
 }
 */
 public void toggleEnabled() {
 setEnabled(!isEnabled());
 }

 @Override
 protected void initialize(Application app) {
 mainWindow = new Container();

 // mainWindow.addChild(new Label("Inventory", new ElementId("title")));
 Label o = mainWindow.addChild(new Label("Inventory", new ElementId("title")));
 o.setFontSize(12);
 o.setPreferredSize(new Vector3f(50, 25, 0));
 o.setTextHAlignment(HAlignment.Center);
 Label f = mainWindow.addChild(new Label("Default Cube", new ElementId("title")));
 f.setTextHAlignment(HAlignment.Center);
 f.setFontSize(12);
 f.setPreferredSize(new Vector3f(50, 25, 0));
 Panel[][] data = new Panel[4][8];
 Panel[][] data1 = new Panel[4][8];
 Label slot1 = new Label("1");
 Label slot2 = new Label("2");
 Label slot3 = new Label("3");
 Label slot4 = new Label("4");
 Label slot5 = new Label("5");
 Label slot6 = new Label("6");
 Label slot7 = new Label("7");
 Label slot8 = new Label("8");
 Label slot9 = new Label("1");
 Label slot10 = new Label("2");
 Label slot11 = new Label("3");
 Label slot12 = new Label("4");
 Label slot13 = new Label("5");
 Label slot14 = new Label("6");
 Label slot15 = new Label("7");
 Label slot16 = new Label("8");
 Label slot17 = new Label("1");
 Label slot18 = new Label("2");
 Label slot19 = new Label("3");
 Label slot20 = new Label("4");
 Label slot21 = new Label("5");
 Label slot22 = new Label("6");
 Label slot23 = new Label("7");
 Label slot24 = new Label("8");
 Label slot25 = new Label("1");
 Label slot26 = new Label("2");
 Label slot27 = new Label("3");
 Label slot28 = new Label("4");
 Label slot29 = new Label("5");
 Label slot30 = new Label("6");
 Label slot31 = new Label("7");
 Label slot32 = new Label("8");
 Label slot33 = new Label("1");
 Label slot34 = new Label("2");
 Label slot35 = new Label("3");
 Label slot36 = new Label("4");
 Label slot37 = new Label("5");
 Label slot38 = new Label("6");
 Label slot39 = new Label("7");
 Label slot40 = new Label("8");
 Label slot41 = new Label("1");
 Label slot42 = new Label("2");
 Label slot43 = new Label("3");
 Label slot44 = new Label("4");
 Label slot45 = new Label("5");
 Label slot46 = new Label("6");
 Label slot47 = new Label("7");
 Label slot48 = new Label("8");
 Label slot49 = new Label("1");
 Label slot50 = new Label("2");
 Label slot51 = new Label("3");
 Label slot52 = new Label("4");
 Label slot53 = new Label("5");
 Label slot54 = new Label("6");
 Label slot55 = new Label("7");
 Label slot56 = new Label("8");
 Label slot57 = new Label("1");
 Label slot58 = new Label("2");
 Label slot59 = new Label("3");
 Label slot60 = new Label("4");
 Label slot61 = new Label("5");
 Label slot62 = new Label("6");
 Label slot63 = new Label("7");
 Label slot64 = new Label("8");

 slot2.setPreferredSize(new Vector3f(50, 25, 0));
 slot3.setPreferredSize(new Vector3f(50, 25, 0));
 slot4.setPreferredSize(new Vector3f(50, 25, 0));
 slot5.setPreferredSize(new Vector3f(50, 25, 0));
 slot6.setPreferredSize(new Vector3f(50, 25, 0));
 slot7.setPreferredSize(new Vector3f(50, 25, 0));
 slot8.setPreferredSize(new Vector3f(50, 25, 0));

 data[0][0] = slot1;
 data[0][1] = slot2;
 data[0][2] = slot3;
 data[0][3] = slot4;
 data[0][4] = slot5;
 data[0][5] = slot6;
 data[0][6] = slot7;
 data[0][7] = slot8;
 data[1][0] = slot9;
 data[1][1] = slot10;
 data[1][2] = slot11;
 data[1][3] = slot12;
 data[1][4] = slot13;
 data[1][5] = slot14;
 data[1][6] = slot15;
 data[1][7] = slot16;
 data[2][0] = slot17;
 data[2][1] = slot18;
 data[2][2] = slot19;
 data[2][3] = slot20;
 data[2][4] = slot21;
 data[2][5] = slot22;
 data[2][6] = slot23;
 data[2][7] = slot24;
 data[3][0] = slot25;
 data[3][1] = slot26;
 data[3][2] = slot27;
 data[3][3] = slot28;
 data[3][4] = slot29;
 data[3][5] = slot30;
 data[3][6] = slot31;
 data[3][7] = slot32;

 CustomGridPanel ola = new CustomGridPanel(new ArrayGridModel<>(data));
ola.getModel().setCell(3, 7, data[3][7]);
ola.setVisibleRows(4);

ola.setVisibleColumns(8);
 ola.setInsets(new Insets3f(10, 10, 0, 10));
 System.err.println(""+ola.getModel().getColumnCount());
 System.err.println(""+ola.getModel().getRowCount());
//ola.setPreferredSize(new Vector3f(400, 400, 0));

 mainWindow.addChild(ola);
 // ola.setPreferredSize(new Vector3f(25, 350, 0));

 mainWindow.addChild(new Label("Inventory", new ElementId("title")));
 data1[0][0] = slot33;
 data1[0][1] = slot34;
 data1[0][2] = slot35;
 data1[0][3] = slot36;
 data1[0][4] = slot37;
 data1[0][5] = slot38;
 data1[0][6] = slot39;
 data1[0][7] = slot40;
 data1[1][0] = slot41;
 data1[1][1] = slot42;
 data1[1][2] = slot43;
 data1[1][3] = slot44;
 data1[1][4] = slot45;
 data1[1][5] = slot46;
 data1[1][6] = slot47;
 data1[1][7] = slot48;
 data1[2][0] = slot49;
 data1[2][1] = slot50;
 data1[2][2] = slot51;
 data1[2][3] = slot52;
 data1[2][4] = slot53;
 data1[2][5] = slot54;
 data1[2][6] = slot55;
 data1[2][7] = slot56;
 data1[3][0] = slot57;
 data1[3][1] = slot58;
 data1[3][2] = slot59;
 data1[3][3] = slot60;
 data1[3][4] = slot61;
 data1[3][5] = slot62;
 data1[3][6] = slot63;
 data1[3][7] = slot64;
 Container loginPanel=mainWindow.addChild(new Container());
 GridPanel maria = new GridPanel(new ArrayGridModel<>(data1));
 loginPanel.addChild(maria);
 maria.setVisibleRows(4);
maria.setVisibleColumns(8);
 mainWindow.addChild(new Label("Inventory", new ElementId("title")));
 mainWindow.addChild(new Label("Inventory", new ElementId("title")));
 mainWindow.addChild(new Label("Inventory", new ElementId("title")));
 mainWindow.addChild(new Label("Inventory", new ElementId("title")));
 mainWindow.addChild(new Label("Inventory", new ElementId("title")));

 mainWindow.setPreferredSize(new Vector3f(350, 450, 0));
 int height = app.getCamera().getHeight();
 Vector3f pref = mainWindow.getPreferredSize().clone();

 float standardScale = getState(MainMenuState.class).getStandardScale();
 pref.multLocal(1.5f * standardScale);

 // With a slight bias toward the top
 float y = height * 0.9f + pref.y * 0.0f;

 mainWindow.setLocalTranslation(250 * standardScale, y, 0);

 InputMapper inputMapper = GuiGlobals.getInstance().getInputMapper();
 inputMapper.addDelegate(MainGameFunctions.F_IN_GAME_INVENTORY, this, "toggleEnabled");
 }

 @Override
 protected void cleanup(Application app) {

 InputMapper inputMapper = GuiGlobals.getInstance().getInputMapper();
 inputMapper.removeDelegate(MainGameFunctions.F_IN_GAME_INVENTORY, this, "toggleEnabled");
 }

 @Override
 protected void onEnable() {
 Node gui = ((Main) getApplication()).getGuiNode();
 gui.attachChild(mainWindow);
 }

 @Override
 protected void onDisable() {
 mainWindow.removeFromParent();
 }

}