math
Legacy Member
yo, ik ben bezig met een gui te maken waarop er een jtextarea of jtextpane komt met daarin namen van klanten. Maar als ik de tekst erin zet krijg ik een error. Als ik op de error klik selecteer het de for lus: for ( String klanten : dc.geefKlanten())
dc.geefKlanten geeft een array van Strings terug.
dc.geefKlanten geeft een array van Strings terug.
Code:
package gui;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JOptionPane;
import javax.swing.WindowConstants;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextPane;
import domein.DomeinController;
/**
* This code was edited or generated using CloudGarden's Jigloo
* SWT/Swing GUI Builder, which is free for non-commercial
* use. If Jigloo is being used commercially (ie, by a corporation,
* company or business for any purpose whatever) then you
* should purchase a license for each developer using Jigloo.
* Please visit www.cloudgarden.com for details.
* Use of Jigloo implies acceptance of these licensing terms.
* A COMMERCIAL LICENSE HAS NOT BEEN PURCHASED FOR
* THIS MACHINE, SO JIGLOO OR THIS CODE CANNOT BE USED
* LEGALLY FOR ANY CORPORATE OR COMMERCIAL PURPOSE.
*/
public class SelecteerKlantScherm extends javax.swing.JPanel implements ActionListener{
private JPanel jPanel1;
private JTextPane TextPane1;
private JButton jButton3;
private JButton jButton2;
private JButton jButton1;
private JTextArea TextArea1;
private JPanel jPanel2;
private DomeinController dc;
private String res;
/**
* Auto-generated main method to display this
* JPanel inside a new JFrame.
*/
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.getContentPane().add(new SelecteerKlantScherm());
frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
public SelecteerKlantScherm() {
super();
initGUI();
}
private void initGUI() {
try {
BorderLayout thisLayout = new BorderLayout();
this.setLayout(thisLayout);
setPreferredSize(new Dimension(400, 300));
{
jPanel1 = new JPanel();
jPanel1.setPreferredSize(new java.awt.Dimension(400, 30));
this.add(jPanel1, BorderLayout.NORTH);
}
{
jPanel2 = new JPanel();
jPanel2.setPreferredSize(new java.awt.Dimension(400, 50));
this.add(jPanel2, BorderLayout.SOUTH);
{
jButton1 = new JButton();
jPanel2.add(jButton1);
jButton1.setText("selecteer");
}
{
jButton2 = new JButton();
jPanel2.add(jButton2);
jButton2.setText("maak nieuwe klant");
}
{
jButton3 = new JButton();
jPanel2.add(jButton3);
jButton3.setText("vorige");
}
}
{
TextPane1 = new JTextPane();
this.add(TextPane1, BorderLayout.CENTER);
TextPane1.setEditable(false);
String res="";
for ( String klanten : dc.geefKlanten())/*hier zit de fout ergens*/{
res+=String.format("%s /n", klanten);
}
TextPane1.setText(res);
}
jButton1.addActionListener(this);
} catch (Exception e) {
e.printStackTrace();
}
}
public void actionPerformed(ActionEvent e){
if(e.getSource()==jButton1){
}
}
}
Code:
java.lang.NullPointerException
at gui.SelecteerKlantScherm.initGUI(SelecteerKlantScherm.java:92)
at gui.SelecteerKlantScherm.<init>(SelecteerKlantScherm.java:54)
at gui.SelecteerKlantScherm.main(SelecteerKlantScherm.java:46)