[RESOLVIDO] Problema em interface gráfica em java

Assuntos Gerais
#1

Erro:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at teste.TesteMenu.inicialixarComponentes(TesteMenu.java:26) at teste.TesteMenu.<init>(TesteMenu.java:14) at teste.TesteMenu.abrir(TesteMenu.java:51) at teste.Teste$1.actionPerformed(Teste.java:51) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022) at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402) at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252) at java.awt.Component.processMouseEvent(Component.java:6525) at javax.swing.JComponent.processMouseEvent(JComponent.java:3324) at java.awt.Component.processEvent(Component.java:6290) at java.awt.Container.processEvent(Container.java:2234) at java.awt.Component.dispatchEventImpl(Component.java:4881) at java.awt.Container.dispatchEventImpl(Container.java:2292) at java.awt.Component.dispatchEvent(Component.java:4703) at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898) at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462) at java.awt.Container.dispatchEventImpl(Container.java:2278) at java.awt.Window.dispatchEventImpl(Window.java:2750) at java.awt.Component.dispatchEvent(Component.java:4703) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758) at java.awt.EventQueue.access$500(EventQueue.java:97) at java.awt.EventQueue$3.run(EventQueue.java:709) at java.awt.EventQueue$3.run(EventQueue.java:703) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86) at java.awt.EventQueue$4.run(EventQueue.java:731) at java.awt.EventQueue$4.run(EventQueue.java:729) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) at java.awt.EventQueue.dispatchEvent(EventQueue.java:728) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

ProjetoPrincipal.java:

[code]package projetoprincipal;

import java.awt.;
import java.awt.event.;
import javax.swing.*;

public class ProjetoPrincipal extends JFrame{
private Container contentPane;
private JMenuBar mnBarra;
private JMenu mnArquivo, mnExemplos;
private JMenuItem miSair, miBotao;

public ProjetoPrincipal() {    
    inicialixarComponentes();    
    definirEventos();    
}    
    
private void inicialixarComponentes() {    
    setTitle("Login no Sistema");    
    setBounds(0, 0, 800, 600);    
    contentPane = getContentPane();    
    mnBarra = new JMenuBar();    
    mnArquivo =  new JMenu("Arquivo");    
    mnArquivo.setMnemonic('A');
    mnExemplos = new JMenu("Exemplos");    
    mnExemplos.setMnemonic('E');   
    miSair = new JMenuItem("Sair", new ImageIcon("sair.jpg"));
    miSair.setAccelerator(KeyStroke.getKeyStroke(    
            KeyEvent.VK_S, ActionEvent.ALT_MASK));    
    miBotao = new JMenuItem("Botao");    
    mnArquivo.add(miSair);    
    mnExemplos.add(miBotao);    
    mnBarra.add(mnArquivo);    
    mnBarra.add(mnExemplos);    
    setJMenuBar(mnBarra);    
}    
    
private void definirEventos() {    
    miSair.addActionListener(new ActionListener() {    
        public void actionPerformed(ActionEvent e) {    
            System.exit(0);    
        }    
    });    
    
    miBotao.addActionListener(new ActionListener() {    
        public void actionPerformed(ActionEvent e) {    
            System.exit(0);          
        }    
    });    
}    
    
    public static void abrir() {    
    ProjetoPrincipal frame = new ProjetoPrincipal();    
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    
    Dimension tela = Toolkit.getDefaultToolkit().getScreenSize();    
    frame.setLocation((tela.width - frame.getSize().width) / 2,    
            (tela.height - frame.getSize().height) / 2);    
    frame.setVisible(true);      
}

} [/code]

#2

Você tem que instanciar o JMenuItem antes de definir propriedades nele

O seu problema está na classe ProjetoPrincipal no metodo " inicialixarComponentes() "

Faça assim para todos os seus JMenuItens


miSair = new JMenuItem();//essa linha que está faltando no seu codigo
miSair.setAccelerator(KeyStroke.getKeyStroke(    
                KeyEvent.VK_S, ActionEvent.ALT_MASK)); 
...