Ich werde verrückt!

[Guest]

Guten Morgen,

entschuldigt gleich mal für den Titel aber ich dreh wirklich am Rad.Ich bekomme seit 1 stunde immer nur eine Nullpointerexception....

Ich poste mal meine Codeschnipsel. Vielleicht weiss einer von euch an was es liegt:

private ArrayList<HeadInfo> test;
	private JButton Uebersicht_Button_Detailview;
	private JTable showtable;
	private TableModel hdM;


.....



{
						jPanel1 = new JPanel();
						GridBagLayout jPanel1Layout = new GridBagLayout();
						jTabbedPane2.addTab("CD Info", null, jPanel1, null);
						jPanel1Layout.rowWeights = new double[] {0.0, 0.1};
						jPanel1Layout.rowHeights = new int[] {804, 7};
						jPanel1Layout.columnWeights = new double[] {0.1};
						jPanel1Layout.columnWidths = new int[] {7};
						jPanel1.setLayout(jPanel1Layout);
						{
							ArrayList<HeadInfo> test = new ArrayList<HeadInfo>();
							int z = Database.get_Zeilen_Count();
							Database.Fill_ArrayList(test, z);
							TableModel hdM = new TableModel_DB(test);
							JTable showtable = new JTable(hdM);
							JScrollPane sp_show = new JScrollPane(showtable);
						
							sp_show.setPreferredSize(new java.awt.Dimension(600, 400));
							jPanel1.add(sp_show, new GridBagConstraints(0, 0, 1, 1, 0.0, 0.0, GridBagConstraints.CENTER, GridBagConstraints.BOTH, new Insets(0, 0, 0, 0), 0, 0));
						}	
						{
							Uebersicht_Button_Detailview = new JButton();
							jPanel1.add(Uebersicht_Button_Detailview, new GridBagConstraints(0, 1, 1, 1, 0.0, 0.0, GridBagConstraints.WEST, GridBagConstraints.NONE, new Insets(0, 30, 0, 0), 0, 0));
							Uebersicht_Button_Detailview.setText("Details");
							Uebersicht_Button_Detailview.addMouseListener(new MouseAdapter() {
								public void mousePressed(MouseEvent evt) {
									try {
										Uebersicht_Button_DetailviewMousePressed(evt);
									} catch (ClassNotFoundException e) {
										// TODO Auto-generated catch block
										e.printStackTrace();
									} catch (SQLException e) {
										// TODO Auto-generated catch block
										e.printStackTrace();
									}
								}
							});
						}
					}
				}

				}

nun der Mouseevent:

	private void Uebersicht_Button_DetailviewMousePressed(MouseEvent evt) throws ClassNotFoundException, SQLException {
		ArrayList<HeadInfo> test2 = new ArrayList<HeadInfo>();
		int x[] = showtable.getSelectedRows();

und genau : int x[] = showtable.getSelectedRows(); spuckt die Exception aus...Ich habe jeddoch in der Jtable etwas ausgewählt.


Exception:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at Java_Projekt_BA_FINAL.Java_Projekt_BA_FINAL.GUI.Uebersicht_Button_DetailviewMousePressed(GUI.java:3154)
	at Java_Projekt_BA_FINAL.Java_Projekt_BA_FINAL.GUI.access$22(GUI.java:3152)
	at Java_Projekt_BA_FINAL.Java_Projekt_BA_FINAL.GUI$25.mousePressed(GUI.java:2773)
	at java.awt.AWTEventMulticaster.mousePressed(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.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)

Wäre für jede Hilfe Dankbar.

 

[The_S]

JTable showtable = new JTable(hdM);

wird zu

showtable = new JTable(hdM);

 

[Gast]

Immernoch die gleiche Exception!

 

[Gast]

Ok nun hat es geklappt. Hab es bei dem Model und Scrollpane auch so gemacht. Danke für den Support.Ging wieder ratz fatz!

 

[ARadauer]

das thema würd ich mir generell nochmal anschaun

public class Test {

   public static String str; 

   public static void main(String[] args) throws IOException {

      String str = "test"; 
      doSomething();
   }

   public static void doSomething(){
      System.out.println(str);
   }


}

warum hier null ausgegeben wird sollte dir klar sein, wenn du innerhalb einer methode eine variable definierst die genau so heiß wie eine die für die ganze klasse gültig ist, wird innerhalb der methode die klassenvariable nicht verwendet....