Olá Pessoal,
Tenho um Class JanelaPrincipal com um menu, que quando clico em Cadastrar deveria chamar a classe JanelaCadastro, mas não funciona, não sei pq, aparece o seguinte erro:
[color=“red”]Exception in thread “AWT-EventQueue-0” java.lang.NullPointerException
at java.awt.Container.addImpl(Unknown Source)
at java.awt[/color].Container.add(Unknown Source)
at JanelaCadastro.<init>(JanelaCadastro.java:36)
at Janelas.getJanelaCadastro(Janelas.java:25)
at JanelaPrincipal.Cadastrar(JanelaPrincipal.java:105)
at JanelaPrincipal.actionPerformed(JanelaPrincipal.java:94)
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.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(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)[/color]
A Classe Janelacadastro está assim:
import javax.swing.JFrame;
import java.awt.Container;
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class JanelaCadastro extends JFrame implements ActionListener{
JButton Cadastrar;
JButton Cancelar;
JLabel Lmarca;
JTextField Marca;
JLabel Lmodelo;
JTextField Modelo;
JLabel Lcor;
JTextField Cor;
JLabel Lano;
JTextField Ano;
JLabel Lobservacoes;
JTextArea Observacoes;
public JanelaCadastro () {
Cadastrar = new JButton("Cadastrar");
Cancelar = new JButton("Cancelar");
Cadastrar.addActionListener(this);
Cancelar.addActionListener(this);
Container c = getContentPane();
c.setLayout(new FlowLayout());
c.add(Lmarca);
c.add(Marca);
c.add(Lmodelo);
c.add(Modelo);
c.add(Lcor);
c.add(Cor);
c.add(Lano);
c.add(Ano);
c.add(Lobservacoes);
c.add(Observacoes);
c.add(Cadastrar);
c.add(Cancelar);
pack();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
}
public void actionPerformed(ActionEvent e) {
}
}
Agradeço,
Mauro Santos