java - JOptionPane 上的 ActionListener

Question

我正在学习有关如何创建自定义对话框的 Oracle 教程:http://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html

我有两个按钮:Save Object 和 Delete Object，点击它们会执行一段特定的代码。不幸的是，我似乎无法将任何 ActionListener 添加到 JOptionPane 按钮，因此当它们被点击时没有任何反应。

任何人都可以帮我告诉我该怎么做吗？到目前为止，这是我为对话框设置的类:

class InputDialogBox extends JDialog implements ActionListener, PropertyChangeListener {
    private String typedText = null;
    private JTextField textField;

    private JOptionPane optionPane;

    private String btnString1 = "Save Object";
    private String btnString2 = "Delete Object";

    /**
     * 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 InputDialogBox(Frame aFrame, int x, int y) {
        super(aFrame, true);

        setTitle("New Object");

        textField = new JTextField(10);

        //Create an array of the text and components to be displayed.
        String msgString1 = "Object label:";

        Object[] array = {msgString1, 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.PLAIN_MESSAGE,
                JOptionPane.YES_NO_OPTION,
                null,
                options,
                options[0]);


        setSize(new Dimension(300,250));
        setLocation(x, y);

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

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

        addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent we) {
                /*
                 * Instead of directly closing the window,
                 * we're going to change the JOptionPane's
                 * value property.
                 */
                optionPane.setValue(new Integer(
                        JOptionPane.CLOSED_OPTION));
            }
        });

        //Ensure the text field always gets the first focus.
        addComponentListener(new ComponentAdapter() {
            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);
    }

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

    /** This method reacts to state changes in the option pane. */
    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 (ucText != null ) {
                    //we're done; clear and dismiss the dialog
                    clearAndHide();
                } else {
                    //text was invalid
                    textField.selectAll();
                    JOptionPane.showMessageDialog(
                                InputDialogBox.this,
                                    "Please enter a label",
                                    "Try again",
                                    JOptionPane.ERROR_MESSAGE);
                    typedText = null;
                    textField.requestFocusInWindow();
                }
            } else { //user closed dialog or clicked delete
               // Delete the object ...

                typedText = null;
                clearAndHide();
            }
        }
    }

    /** This method clears the dialog and hides it. */
    public void clearAndHide() {
        textField.setText(null);
        setVisible(false);
    }

Answer 1

我认为您错过了 JOptionPane 的要点。它具有显示自己的对话框的能力...

public class TestOptionPane02 {

    public static void main(String[] args) {
        new TestOptionPane02();
    }

    public TestOptionPane02() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException ex) {
                } catch (InstantiationException ex) {
                } catch (IllegalAccessException ex) {
                } catch (UnsupportedLookAndFeelException ex) {
                }

                JTextField textField = new JTextField(10);

                String btnString1 = "Save Object";
                String btnString2 = "Delete Object";

                //Create an array of the text and components to be displayed.
                String msgString1 = "Object label:";
                Object[] array = {msgString1, textField};
                //Create an array specifying the number of dialog buttons
                //and their text.
                Object[] options = {btnString1, btnString2};

                int result = JOptionPane.showOptionDialog(null, array, "", JOptionPane.YES_NO_OPTION, JOptionPane.PLAIN_MESSAGE, "New Object", options, options[0]);
                switch (result) {
                    case 0:
                        System.out.println("Save me");
                        break;
                    case 1:
                        System.out.println("Delete me");
                        break;
                }
            }
        });
    }
}

要手动完成，您将需要做更多的工作。

首先，您将不得不监听面板的属性更改事件，寻找对 JOptionPane.VALUE_PROPERTY 的更改并忽略 JOptionPane.UNINITIALIZED_VALUE 的任何值...

一旦您检测到更改，您将需要处理您的对话框。

您需要提取通过 JOptionPane#getValue 方法选择的值，该方法返回一个 Object。您将不得不自己打断该值的含义...

不用说，JOptionPane.showXxxDialog 方法会为您完成这一切...

现在，如果您担心必须完成对话框的所有设置，我会编写一个实用程序方法，要么完全完成它，要么采用所需的参数……但这就是我

已更新

不知道为什么我没有早点想到...

传递JButton 数组而不是传递String 数组作为选项参数。这样您就可以附加自己的监听器。

options - an array of objects indicating the possible choices the user can make; if the objects are components, they are rendered properly; non-String objects are rendered using their toString methods; if this parameter is null, the options are determined by the Look and Feel