java - JComboBox:ItemStateChange 上的行为

Question

所以我有一个要求，基于从 JComboBox 中选择一个项目，我需要向用户显示一个选择确认对话框。我所做的是添加一个ItemListener，然后根据一定的逻辑，弹出这个对话框。

我面临的相当棘手的问题是对话框首先弹出(即使 ComboBox 项目选择处于打开状态)，我必须单击两次以确认我的选择。第一个是关闭 ComboBox 弹出窗口，第二个是确认对话框中的实际那个。

这是一个强调我的问题的 SSCCE:

import java.awt.event.ItemEvent;
import javax.swing.JOptionPane;

public class TestFrame extends javax.swing.JFrame {

    /**
     * Creates new form TestFrame
     */
    public TestFrame() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
    private void initComponents() {

        jLabel1 = new javax.swing.JLabel();
        selectCombo = new javax.swing.JComboBox();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jLabel1.setText("Select Option");

        selectCombo.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Option 1", "Option 2", "Option 3", "Option 4" }));
        selectCombo.addItemListener(new java.awt.event.ItemListener() {
            public void itemStateChanged(java.awt.event.ItemEvent evt) {
                selectComboItemStateChanged(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jLabel1)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(selectCombo, javax.swing.GroupLayout.PREFERRED_SIZE, 155, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(168, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(22, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1)
                    .addComponent(selectCombo, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(19, 19, 19))
        );

        pack();
    }// </editor-fold>//GEN-END:initComponents

    private void selectComboItemStateChanged(java.awt.event.ItemEvent evt) {//GEN-FIRST:event_selectComboItemStateChanged
        if (evt.getStateChange() == ItemEvent.SELECTED) {
            String selectedItem = (String) selectCombo.getSelectedItem();
            if (selectedItem == null || selectedItem.equals("Option 1")) {
                return;
            } else {
                JOptionPane.showConfirmDialog(this, "Do you want to change option to - " + selectedItem + " ?", "Confirm Option Selection", JOptionPane.YES_NO_OPTION);
            }
        }
    }//GEN-LAST:event_selectComboItemStateChanged

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {

        try {
             javax.swing.UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(TestFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(TestFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(TestFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(TestFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                new TestFrame().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JLabel jLabel1;
    private javax.swing.JComboBox selectCombo;
    // End of variables declaration//GEN-END:variables
}

有人能告诉我我做错了什么吗？我希望在用户选择完他的选项并且 ComboBox 弹出窗口关闭后弹出确认对话框。

Answer 1

我会通过调用适当的方法来做到这一点:

else {
            selectCombo.setPopupVisible(false);
            JOptionPane.showConfirmDialog(this, "Do you want to change option to - " + selectedItem
                    + " ?", "Confirm Option Selection", JOptionPane.YES_NO_OPTION);
        }