JOptionPane - 检查用户输入并防止关闭，直到满足条件

问题描述

除非满足用户输入字段的条件，否则有人可以告诉我是否有一种方便的方法可以阻止 JOptionPane 关闭，除非满足用户输入字段的条件？

Please can someone tell me if there is a convenient way of prevent JOptionPane from closing upon clicking OK unless the conditions for user input fields are met?

或者我别无选择，只能使用 JFrame ？

Or do I have no choice but to use JFrame?

我的验证逻辑到目前为止。似乎没有用，因为按钮因某种原因一次性可点击...

My validation logic so far. Doesn't seem to work because the buttons are one-time clickable to some reason...

final JDialog dialog3 = new JDialog(OmniGUI.getFrame(), "Create new Node - id:" + newNodeID);
dialog3.setContentPane(theOPane);
dialog3.setDefaultCloseOperation(JDialog.DO_NOTHING_ON_CLOSE);

theOPane.addPropertyChangeListener(new PropertyChangeListener(){
   public void propertyChange(PropertyChangeEvent e) {

       if(e.getSource() == theOPane){
           String val = (String) ((JOptionPane) e.getSource()).getValue();

           if(val=="Create"){
               System.out.println("Checking content");

               if(!valid){
                   System.out.println("closing the window");

                   dialog3.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
                   dialog3.removeAll();
                   dialog3.dispatchEvent(new WindowEvent(dialog3, WindowEvent.WINDOW_CLOSING));
               }

           }
       }
   }
});

    dialog3.setLocation(p);
    dialog3.pack();
    dialog3.setVisible(true);

推荐答案

您可以创建自己的自定义 JDialog 在关闭或继续之前检查用户输入等。看到这个链接：

You can create your own Custom JDialog to check user input etc before closing or moving on. See this link:

这是我做的一个例子：

如果输入错误/无文本并单击Enter，将显示验证消息：

If you type wrong/no text and click Enter a validation message will be displayed:

如果您单击 X 以关闭对话框或单击取消，则还会显示验证消息：

If you click X to close Dialog or click Cancel a validation message will be shown also:

如果输入了正确的文字（在这个案例大卫）并点击输入显示一条消息并退出 JDialog ：

If correct text is entered (in this case "David") and enter is clicked a message is shown and JDialog is exited:

CustomDialog.java：

import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import javax.swing.JDialog;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

class CustomDialog extends JDialog
        implements ActionListener,
        PropertyChangeListener {

    private String typedText = null;
    private JTextField textField;
    private String magicWord;
    private JOptionPane optionPane;
    private String btnString1 = "Enter";
    private String btnString2 = "Cancel";

    /**
     * Returns null if the typed string was invalid; otherwise, returns the
     * string as the user entered it.
     */
    public String getValidatedText() {
        return typedText;
    }

    /**
     * Creates the reusable dialog.
     */
    public CustomDialog(Frame aFrame, String aWord) {
        super(aFrame, true);

        magicWord = aWord.toUpperCase();
        setTitle("Quiz");

        textField = new JTextField(10);

        //Create an array of the text and components to be displayed.
        String msgString1 = "What was Dr. SEUSS's real last name?";
        String msgString2 = "(The answer is \"" + magicWord
                + "\".)";
        Object[] array = {msgString1, msgString2, textField};

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

        //Create the JOptionPane.
        optionPane = new JOptionPane(array,
                JOptionPane.QUESTION_MESSAGE,
                JOptionPane.YES_NO_OPTION,
                null,
                options,
                options[0]);

        //Make this dialog display it.
        setContentPane(optionPane);

        //Handle window closing correctly.
        setDefaultCloseOperation(DISPOSE_ON_CLOSE);

        //Ensure the text field always gets the first focus.
        addComponentListener(new ComponentAdapter() {
            @Override
            public void componentShown(ComponentEvent ce) {
                textField.requestFocusInWindow();
            }
        });

        //Register an event handler that puts the text into the option pane.
        textField.addActionListener(this);

        //Register an event handler that reacts to option pane state changes.
        optionPane.addPropertyChangeListener(this);
        pack();
    }

    /**
     * This method handles events for the text field.
     */
    @Override
    public void actionPerformed(ActionEvent e) {
        optionPane.setValue(btnString1);
    }

    /**
     * This method reacts to state changes in the option pane.
     */
    @Override
    public void propertyChange(PropertyChangeEvent e) {
        String prop = e.getPropertyName();

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

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

            //Reset the JOptionPane's value.
            //If you don't do this, then if the user
            //presses the same button next time, no
            //property change event will be fired.
            optionPane.setValue(
                    JOptionPane.UNINITIALIZED_VALUE);

            if (btnString1.equals(value)) {
                typedText = textField.getText();
                String ucText = typedText.toUpperCase();
                if (magicWord.equals(ucText)) {
                    JOptionPane.showMessageDialog(this, "Correct answer given");
                    exit();
                } else {
                    //text was invalid
                    textField.selectAll();
                    JOptionPane.showMessageDialog(this,
                            "Sorry, \"" + typedText + "\" "
                            + "isn't a valid response.\n"
                            + "Please enter "
                            + magicWord + ".",
                            "Try again",
                            JOptionPane.ERROR_MESSAGE);
                    typedText = null;
                    textField.requestFocusInWindow();
                }
            } else { //user closed dialog or clicked cancel
                JOptionPane.showMessageDialog(this, "It's OK.  "
                        + "We won't force you to type "
                        + magicWord + ".");
                typedText = null;
                exit();
            }
        }
    }

    /**
     * This method clears the dialog and hides it.
     */
    public void exit() {
        dispose();
    }

    public static void main(String... args) {
        //create JDialog and components on EDT
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new CustomDialog(null, "David").setVisible(true);
            }
        });
    }
}

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