Question

我看到这已被多次询问并提前道歉，如果我只是错过了一些简单的事情......

我创建了一个自定义JDialog，其中包含Java文档here中提供的示例，以及here提出的类似问题。

我的主应用程序是一个JFrame，它包含一个JPanel，其中包含一组显示各种员工姓名的JButtons。我已经为每个调用上述JDialog的JButton添加了一个自定义ActionListener：

//inner class for handling user button pushes
private class UserButtonHandler implements ActionListener
{
    //handle button event
    @Override
    public void actionPerformed(ActionEvent event)
    {
        statusDialog = new ChangeDialog(statusWindow);
        statusDialog.setVisible(true);
        statusDialog.setLocationRelativeTo(null);

        //set title for dialog box
        String dialogTitle = "Status change for " + event.getActionCommand();
        statusDialog.setTitle(dialogTitle);

        statNum = ((ChangeDialog) statusDialog).getInputStatus();
        System.out.println("Current num is: " + statNum);

        //statNum = statusDialog.getInputStatus();

    }
}

以下是自定义JDialog（ChangeDialog）的类：

class ChangeDialog extends JDialog implements ActionListener, PropertyChangeListener
{
    //create panel where users can modify their status
    private final ChangePanel empStatusChangePanel;

    //text of buttons in dialog
    private String btnString1 = "OK";
    private String btnString2 = "Cancel";
    private String btnString3 = "Clear Time-Off";

    private JOptionPane statusPane;

    //determines message to return for user input
    private int inputStatus; 

    public ChangeDialog(JFrame statusFrame)
    {
        empStatusChangePanel = new ChangePanel();

        //create an array specifying the number
        //of dialog buttons and their text
        Object[] options = {btnString1, btnString2, btnString3};

        //create the JOptionPane
        statusPane = new JOptionPane(empStatusChangePanel,
                JOptionPane.PLAIN_MESSAGE,
                JOptionPane.YES_NO_CANCEL_OPTION,
                null,
                options,
                options[0]);

        //set contents of dialog
        setContentPane(statusPane);

        //handle window closing
        setDefaultCloseOperation(DISPOSE_ON_CLOSE);

        //register event handler for changes in status pane state
        statusPane.addPropertyChangeListener(this);
        pack();

    }

    @Override
    public void actionPerformed(ActionEvent e)
    {
        statusPane.setValue(btnString1);
    }

    @Override
    public void propertyChange(PropertyChangeEvent e)
    {
        String prop = e.getPropertyName();

        if (isVisible()
                && (e.getSource() == statusPane)
                && (JOptionPane.VALUE_PROPERTY.equals(prop)))
        {
            Object value = statusPane.getValue();

            if (value == JOptionPane.UNINITIALIZED_VALUE)
            {
                //ignore reset
                return;
            }

            //Reset the JOptionPane's value. If this is not done,
            //then if the user presses the same button next time,
            //no property change event will be fired
            statusPane.setValue(JOptionPane.UNINITIALIZED_VALUE);

            if(value.equals(btnString1)) //user clicked "OK"
            {
                //validation of user input
                inputStatus = empStatusChangePanel.validateUserInput();

                //handle validation results
                switch (inputStatus)
                {
                case 0: //user input is good
                    JOptionPane.showMessageDialog(this, "Good input given");
                    dispose();
                    break;

                case 1: //one (or both) of the date pickers are empty
                    JOptionPane.showMessageDialog(this, "PTO pickers can't be empty.",
                            "ERROR", JOptionPane.ERROR_MESSAGE);
                    break;

                case 2:
                case 3: //bad date range (start before end or visa-versa)
                    JOptionPane.showMessageDialog(this, "Bad date range.",
                            "ERROR", JOptionPane.ERROR_MESSAGE);
                    break;

                case 99: //dates are equal
                    JOptionPane.showMessageDialog(this, "Single-day PTO");
                    dispose();
                    break;
                }
            }
            else if(value.equals(btnString3)) //user clicked "Clear Input"
            {
                JOptionPane.showMessageDialog(this, "User clicked 'clear input");
                //more processing should be done here
                empStatusChangePanel.recycle();

                //dispose();
            }
            else //user clicked "Cancel" or closed dialog
            {
                JOptionPane.showMessageDialog(this,  "User closed status window");
                dispose();
            }
        }
    }

    //returns value from user validation
    public int getInputStatus()
    {
        return inputStatus;
    }

}

我需要从自定义对话框中访问方法getInputStatus，但我尝试过的每次尝试都会回来说明：

getInputStatus is undefined for the type JDialog

我已经查看了其他几个类似的帖子，但觉得我在尝试解决这个问题时缺少一些基本的东西（或者我一直在查看代码太久了。）

让我难以理解的另一件事（以及为什么我将其留在第一个片段中）是我将该方法转换为类型ChangeDialog

statNum = ((ChangeDialog) statusDialog).getInputStatus();

它突然有访问权限（这是Eclipse的一个建议，对我来说没有意义）。再次感谢您的帮助。

Answer 1

这就是继承的工作原理，你已经将statusDialog定义为JDialog引用，而JDialog没有getInputStatus方法。要访问ChangeDialog的成员，您必须将statusDialog定义为ChangeDialog的变量。

从自定义JDialog返回值

1 个答案: