Huhu Leute,
ich programmiere grade nen Adressbuch, bin schön am Klassen auslagern pi pa po.
Hier erstmal der Kot.
Ich übergebe die Buttons & die Textfelder an meinen ActionListener, die Buttons werden beim Klick erkannt & alles funktioniert bis dahin, jedoch kriege ich ne nullpointerexception sobald ich den inhalt abfrage..
seht ihr den fehler?
ich programmiere grade nen Adressbuch, bin schön am Klassen auslagern pi pa po.
Hier erstmal der Kot.
Java:
public class CMain
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
CGraphicalUserInterface GUI = new CGraphicalUserInterface();
}
});
}
}
Java:
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.Toolkit;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
public class CGraphicalUserInterface extends JFrame
{
GridBagConstraints c = new GridBagConstraints();
JPanel panel = new JPanel(new GridBagLayout());
Insets insets = new Insets(3, 3, 3, 3);
CGraphicalUserInterface()
{
super("Adressbuch");
setSize(400, 150);
centerWindow(this);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.add(panel);
createButton("Anmelden", 1, 2, panel, c);
createButton("Registration", 0, 2, panel, c);
createLabel("Benutzername", 0, 0, panel, c);
createLabel("Passwort", 0, 1, panel, c);
createTextField(20, 1, 0, panel, c);
JPasswordField pw = new JPasswordField(20);
c.gridx = 1;
c.gridy = 1;
panel.add(pw, c);
setVisible(true);
}
private void centerWindow(JFrame frame)
{
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
int x = screenSize.width;
int y = screenSize.height;
int posX = (x - frame.getWidth()) / 2;
int posY = (y - frame.getHeight()) / 2;
frame.setLocation(posX, posY);
}
private JButton createButton(String text, int posX, int posY, JPanel panel, GridBagConstraints c)
{
JButton button = new JButton(text);
button.addActionListener(new CActionListener(button));
c.gridx = posX;
c.gridy = posY;
c.insets = insets;
panel.add(button, c);
return button;
}
private JTextField createTextField(int length, int posX, int posY, JPanel panel, GridBagConstraints c)
{
JTextField textfield = new JTextField(length);
textfield.addActionListener(new CActionListener(textfield));
c.gridx = posX;
c.gridy = posY;
c.insets = insets;
panel.add(textfield, c);
return textfield;
}
private JLabel createLabel(String text, int posX, int posY, JPanel panel, GridBagConstraints c)
{
JLabel label = new JLabel(text);
c.gridx = posX;
c.gridy = posY;
c.insets = insets;
panel.add(label, c);
return label;
}
}
Java:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JTextField;
public class CActionListener implements ActionListener
{
private JButton button;
private JTextField textfield;
public CActionListener(JButton button)
{
this.button = button;
}
public CActionListener(JTextField textfield)
{
this.textfield = textfield;
}
public void actionPerformed(ActionEvent ae)
{
if (ae.getActionCommand() == "Anmelden")
{
if(isNullOrEmpty(textfield.getText()))
{
System.out.println("Jeah!");
}
}
if (ae.getActionCommand() == "Registration")
{
}
}
private boolean isNullOrEmpty(String s)
{
if (s != null && s != "")
{
return true;
}
else
{
return false;
}
}
}
Ich übergebe die Buttons & die Textfelder an meinen ActionListener, die Buttons werden beim Klick erkannt & alles funktioniert bis dahin, jedoch kriege ich ne nullpointerexception sobald ich den inhalt abfrage..
seht ihr den fehler?