Aufruf Methode anderer Klasse

[pappender]

public class ControllerViewEinsatzplan {
   
   
    private DatabaseModel databaseModel;
    private ViewEinsatzplan viewEinsatzplan;
    private JPanel mainPanel;
    private String[] tableData;
    private String[] tableColumnName;
   
   
    public ControllerViewEinsatzplan() {
        databaseModel = new DatabaseModel();
        viewEinsatzplan = new ViewEinsatzplan(this);
    }
   
   
    public JPanel buildView() {
        mainPanel = viewEinsatzplan.getPanel();
        return mainPanel;
    }
   
   
    public void getTableData() {
        tableData = databaseModel.getTableData();
        tableColumnName = databaseModel.getTableColumnsName();
        viewEinsatzplan.setTableData();
    }
   
   
}

Warum bekomme ich in der Methode 'getTableData' beim Aufruf dieser Methode: viewEinsatzplan.setTableData(); eine NullPointerException?​

 

[Elenteria]

Der Fehler müsste irgendwo in ViewEinsatzplan sein. Wie sieht denn die Klasse ViewEinsatzplan aus?

 

[Joose]

viewEinsatzplan.setTableData(); eine NullPointerException?

Es ist immer praktisch den StackTrace und den dazugehörigen Code zu posten

 

[pappender]

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at de.swing.mvc.ids.ControllerViewEinsatzplan.getTableData(ControllerViewEinsatzplan.java:30)
at de.swing.mvc.ids.ViewEinsatzplan.<init>(ViewEinsatzplan.java:89)
at de.swing.mvc.ids.ControllerViewEinsatzplan.<init>(ControllerViewEinsatzplan.java:17)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at de.swing.mvc.ids.Controller.handleMenu(Controller.java:27)
at de.swing.mvc.ids.View$MenuActionListener.actionPerformed(View.java:83)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.AbstractButton.doClick(Unknown Source)
at javax.swing.plaf.basic.BasicMenuItemUI.doClick(Unknown Source)
at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)


und Nochmal die Methode in der andere Klasse, sie kann nichts, ist nur ein Test:

    public void setTableData() {
        System.out.println("testSetTable");
    }

 

[Joose]

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at de.swing.mvc.ids.ControllerViewEinsatzplan.getTableData(ControllerViewEinsatzplan.java:30)
....
und Nochmal die Methode in der andere Klasse, sie kann nichts, ist nur ein Test:

Und was macht deine Methode getTableData weil dort passiert der Fehler und nicht in setTableData

 

[Elenteria]

Ah da haben wir ja das Problem. Du versuchst im Konstruktor von ControllerViewEinsatzplan ein neuen ViewEinsatzplan zu erstellen. Der Konstruktor von ViewEinsatzplan ruft dann die getTableData() des Controllers auf welcher wiederum für die Methode die View benötigt. Diese ist aber beim Aufruf der Methode noch gar nicht mit fertig erstellt.