我仅从以下对象得到null：对象selectedValue = jPane.getValue（）; （jPane =新的JOptionPane（...）

Question

    private void cancelButtonPressed() {  
    jPane = new JOptionPane("quit?", JOptionPane.QUESTION_MESSAGE, JOptionPane.YES_NO_OPTION, null, buttons, buttons[1]);
    jPane.setName("WPane");
    dialog = jPane.createDialog(jPane.getParent(), "Confirm Dialog");

    dialog.setVisible(true);
    dialog.dispose();

    Object selectedValue = jPane.getValue();
    System.out.println("selectedValue:" + selectedValue);
    if(selectedValue == null)
        System.out.println("selectedValue:" + selectedValue);
        //return CLOSED_OPTION;
    if(buttons == null) {
        if(selectedValue instanceof Integer) {
            //return ((Integer)selectedValue).intValue();
            System.out.println("selectedValue instanceof Integer, selectedValue:" + selectedValue);
        //return CLOSED_OPTION;
        }
    }
    for(int counter = 0, maxCounter = buttons.length;
        counter < maxCounter; counter++) {
        if(buttons[counter].equals(selectedValue)){
            System.out.println("buttons[counter].equals(selectedValue) selectedValue:" + selectedValue);
            //return counter;
        }
    }
    //return CLOSED_OPTION;
}

在构造函数中，我设置按钮的名称：

    buttons[0]= new JButton("Yes");
    buttons[1]= new JButton("No");
    buttons[0].setName("Yes_Next_Btn");
    buttons[1].setName("No_Back_Btn");

问题是，我需要setNames使用以下组件：JOptionPane和按钮。所以我不用：JOptionPane.showConfirmDialog。

并且在这种情况下：当我单击按钮（是，否）时，只有单击“ X”，我不会得到任何值，退出时我得到null。

Answer 1

如果将JButtons选项作为放入JOptionPane，则需要指定单击它们时发生的情况。由于您似乎没有任何按钮Action或ActionListener绑定到按钮，因此什么也没有发生。

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;

public class JOptionPaneTest {

    public void createAndShowJOptionPane() {
        final JButton b1 = new JButton("Yes, please");
        b1.setName("yes_please");
        final JButton b2 = new JButton("No, thx");
        b2.setName("no_thx");
        final JButton b3 = new JButton("Leave me alone");
        b3.setName("leave_me_alone");
        Object[] options = new Object[]{b1, b2, b3};

        final JOptionPane optionPane = new JOptionPane("Message", JOptionPane.QUESTION_MESSAGE, JOptionPane.YES_NO_CANCEL_OPTION, null, options, options[2]);
        final JDialog dialog = optionPane.createDialog("Title");
        b1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println(b1.getText());
                optionPane.setValue(0);
                dialog.dispose();
            }
        });
        b2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println(b2.getText());
                optionPane.setValue(1);
                dialog.dispose();
            }
        });
        b3.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println(b3.getText());
                optionPane.setValue(2);
                dialog.dispose();
            }
        });
        dialog.setVisible(true);

        if ((Integer)optionPane.getValue() == 0) {
            System.out.println("Woohoo!");
        }
    }

    public static void main(String[] argv) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JOptionPaneTest test = new JOptionPaneTest();
                test.createAndShowJOptionPane();
            }
        });
    }
}