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POnullpointerException on a JTextfield with Text in it
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copied!<p>So you guys said you don't have enough information to help me. I'm sorry it's the first time I asked a question in such a forum and I didn't work a long time with Java.</p> <p>So here's my whole code, there could be a lots of faults but I'm glad if you help me to solve them and say me how to do better Java Programming in all. </p> <p><strong>Main Class:</strong></p> <pre><code>public class Main { public static void main(String[] args) { new Main().top(); } void top() { GUI g = new GUI(); } } </code></pre> <p><strong>Class GUI:</strong></p> <pre><code>import java.awt.event.ActionListener; import java.text.SimpleDateFormat; import javax.swing.*; public class GUI { JFrame frame; JPanel panel; static JLabel label; static JLabel username_bezeichnung; static JLabel vorname_bezeichnung; static JLabel nachname_bezeichnung; static JLabel geburtstag_bezeichnung; static JLabel email_bezeichnung; static JLabel passwort_bezeichnung; static JButton registrieren; static JButton login; static JButton registrierenBestätigen; static JTextField username; static JTextField vorname; static JTextField nachname; static JTextField email; static JFormattedTextField geburtstag; static JPasswordField passwort; void gui() { ListenerHome h = new ListenerHome(); ListenerRegistrieren r = new ListenerRegistrieren(); /** * Frames */ // Frame Main frame = new JFrame("Main"); frame.setSize(800, 600); frame.setLocation(600, 200); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); /** * Panels */ // Panel Main panel = new JPanel(); panel.setSize(780, 475); panel.setLayout(null); frame.add(panel); /** * Labels */ // Label Main label = new JLabel(); label.setSize(200, 300); label.setLocation(230, 30); label.setVisible(true); label.setText("Guten Tag, was möchten Sie tun?"); panel.add(label); // Label Username username_bezeichnung = new JLabel(); username_bezeichnung.setBounds(65, 50, 120, 30); username_bezeichnung.setVisible(false); username_bezeichnung.setText("Username"); panel.add(username_bezeichnung); // Label Vorname vorname_bezeichnung = new JLabel(); vorname_bezeichnung.setBounds(65, 90, 120, 30); vorname_bezeichnung.setVisible(false); vorname_bezeichnung.setText("Vorname"); panel.add(vorname_bezeichnung); // Label Nachname nachname_bezeichnung = new JLabel(); nachname_bezeichnung.setBounds(65, 130, 120, 30); nachname_bezeichnung.setVisible(false); nachname_bezeichnung.setText("Nachname"); panel.add(nachname_bezeichnung); // Label Geburtstag geburtstag_bezeichnung = new JLabel(); geburtstag_bezeichnung.setBounds(390, 50, 120, 30); geburtstag_bezeichnung.setVisible(false); geburtstag_bezeichnung.setText("Geburtstag"); panel.add(geburtstag_bezeichnung); // Label E-Mail email_bezeichnung = new JLabel(); email_bezeichnung.setBounds(390, 90, 120, 30); email_bezeichnung.setVisible(false); email_bezeichnung.setText("E-Mail"); panel.add(email_bezeichnung); // Label Passwort passwort_bezeichnung = new JLabel(); passwort_bezeichnung.setBounds(390, 130, 120, 30); passwort_bezeichnung.setVisible(false); passwort_bezeichnung.setText("Passwort"); panel.add(passwort_bezeichnung); /** * Buttons */ // Button registrieren registrieren = new JButton("Registrieren"); registrieren.setLocation(200, 320); registrieren.setSize(120, 50); registrieren.setVisible(true); registrieren.addActionListener(h); panel.add(registrieren); // Button login login = new JButton("Login"); login.setLocation(350, 320); login.setSize(120, 50); login.setVisible(true); login.addActionListener(h); panel.add(login); // Button registrieren bestätigen registrierenBestätigen = new JButton("Registrieren"); registrierenBestätigen.setLocation(390, 350); registrierenBestätigen.setSize(120, 50); registrierenBestätigen.setVisible(false); registrierenBestätigen.addActionListener(r); panel.add(registrierenBestätigen); /** * Textfields */ // Textfield Username username = new JTextField("", 20); username.setBounds(150, 50, 120, 30); username.setVisible(false); panel.add(username); // Textfield Vorname vorname = new JTextField("", 20); vorname.setBounds(150, 90, 120, 30); vorname.setVisible(false); panel.add(vorname); // Textfield Nachname nachname = new JTextField("", 20); nachname.setBounds(150, 130, 120, 30); nachname.setVisible(false); panel.add(nachname); // Textfield Geburtstag geburtstag = new JFormattedTextField(new SimpleDateFormat("dd.MM.yyyy")); geburtstag.setValue(new java.util.Date()); geburtstag.setBounds(475, 90, 120, 30); geburtstag.setVisible(false); panel.add(geburtstag); // Textfield E-Mail email = new JTextField("", 25); email.setBounds(475, 50, 120, 30); email.setVisible(false); panel.add(email); // Passwortfield Passwort passwort = new JPasswordField("", 20); passwort.setBounds(475, 130, 120, 30); passwort.setVisible(false); panel.add(passwort); } } </code></pre> <p><strong>Class ListenerHome</strong></p> <pre><code>import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class ListenerHome implements ActionListener { @Override public void actionPerformed(ActionEvent e) { if (e.getSource() == GUI.registrieren) { GUI.label.setVisible(false); GUI.username_bezeichnung.setVisible(true); GUI.vorname_bezeichnung.setVisible(true); GUI.nachname_bezeichnung.setVisible(true); GUI.geburtstag_bezeichnung.setVisible(true); GUI.email_bezeichnung.setVisible(true); GUI.passwort_bezeichnung.setVisible(true); GUI.registrieren.setVisible(false); GUI.login.setVisible(false); GUI.registrierenBestätigen.setVisible(true); GUI.username.setVisible(true); GUI.vorname.setVisible(true); GUI.nachname.setVisible(true); GUI.email.setVisible(true); GUI.geburtstag.setVisible(true); GUI.passwort.setVisible(true); } } } </code></pre> <p><strong>Class ListenerRegistrieren</strong></p> <pre><code>import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.SQLException; public class ListenerRegistrieren implements ActionListener { public void actionPerformed(ActionEvent e) { if(e.getSource() == GUI.registrierenBestätigen) { addBenutzer(); } } private static void addBenutzer() { try { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); Connection conn = DriverManager.getConnection("jdbc:odbc:MSAccess"); PreparedStatement pstm; String sql = "Insert Into Benutzer ('Benutername', 'Vorname', 'Nachname', 'E-Mail') values ('?','?','?','?')"; pstm = conn.prepareStatement(sql); // SQL Statements pstm.setString(1, GUI.username.getText()); pstm.setString(2, GUI.vorname.getText()); pstm.setString(3, GUI.nachname.getText()); pstm.setString(4, GUI.email.getText()); pstm.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } } } </code></pre> <p><strong>Stack Trace</strong></p> <pre><code>java.lang.NullPointerException at sun.jdbc.odbc.JdbcOdbcPreparedStatement.clearParameter(Unknown Source) at sun.jdbc.odbc.JdbcOdbcPreparedStatement.setChar(Unknown Source) at sun.jdbc.odbc.JdbcOdbcPreparedStatement.setString(Unknown Source) at verwaltung.ListenerRegistrieren.addBenutzer(ListenerRegistrieren.java:37) at verwaltung.ListenerRegistrieren.actionPerformed(ListenerRegistrieren.java:20) 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.plaf.basic.BasicButtonListener.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$200(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$1.doIntersectionPrivilege(Unknown Source) at java.security.ProtectionDomain$1.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$1.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) </code></pre> <p>I hope you can help me better now. Thanks for your help guys! </p>

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