如何删除 jbutton 的颜色保持

Question

When the validation is correct the si button is placed green, then I perform a incorrect validation and the si button is still in that color.

I tried to select the original color of both buttons, but it does not work for the si button.

private void btn_validarActionPerformed(java.awt.event.ActionEvent evt) {                                            
    String w_correo = caja_correo.getText();
    Pattern p_correo1 = Pattern.compile("^(?=.{1,129}$)[a-zA-Z][a-zA-Z][a-zA-Z]*\\.[a-zA-Z][a-zA-Z][a-zA-Z]*\\.(?:2019|20[2-9][0-9]|2[1-9][0-9]{2}|[3-9][0-9]{3})@([0-9]|[a-z]|[A-Z])+\\.edu.?[a-z]*$");
        Matcher m_correo1 = p_correo1.matcher(w_correo);
     Pattern p_correo2 = Pattern.compile("^(?=.{1,129}$)(?:2018|201[0-7]|200[0-9]|1[0-9]{1,3}|[0-9]{1,3})\\.[a-zA-Z][a-zA-Z][a-zA-Z]*\\.[a-zA-Z][a-zA-Z][a-zA-Z]*@\\w+(?:\\.\\w+)*\\.com\\.co$");
    Matcher m_correo2 = p_correo2.matcher(w_correo);    

    correcto.setBackground(null);  
    incorrecto.setBackground(null);

    if (m_correo1.matches()|| m_correo2.matches()) {
        correcto.setBackground(null);  
        incorrecto.setBackground(null);
        String validacion = "";
        validacion = validacion +  "Direccion de correo electrónico correcta";
        JOptionPane.showMessageDialog(null, validacion);
        correcto.setForeground(Color.GREEN);

    }

    else { 

        String validacion = "";
        if (!m_correo1.matches() || m_correo2.matches()) {
            correcto.setBackground(null);  
            incorrecto.setBackground(null);    
            validacion = validacion + "Direccion de correo electrónico incorrecta";
            JOptionPane.showMessageDialog(null, validacion);
                incorrecto.setBackground(Color.RED);
        }
    }
}

that I must change so that the si button stops holding the green color

Answer 1

Within your correct-block (the one setting the text green) you want to call incorrect.setBackground(null) in order to remove the background color from it. In the other block, you should also remove the green color from the correcto -Button ( setForeground(null) ) to signify a Change to a false answer.

Notice that Swing requires you to call repaint() on a changed UI element, to ensure it is redrawn, otherwise it will only be redrawn after a specific event causes the UI to redraw (for example a change in the JFrame size).

As a hint on the side, you should find more qualifying names for your variables. The ones you picked are very hard to read, since they are all effectively the same, but for some single characters or digits. For example your patterns could be named p_correctEdu and the other p_correctCom .