在 JOptionPane.showOptionDialog() 中设置组件焦点

Question

为了在输入对话框中有自定义按钮标题，我创建了以下代码：

String key = null;
JTextField txtKey = new JTextField();        
int answerKey = JOptionPane.showOptionDialog(this, new Object[] {pleaseEnterTheKey, txtKey}, decryptionKey, JOptionPane.OK_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE, null, new Object[] {okCaption, cancelCaption}, okCaption);        
if (answerKey == JOptionPane.OK_OPTION && txtKey.getText() != null) {
  key = txtKey.getText();
}

如何在显示对话框时将焦点（光标）移动到文本字段？

更新

这对我不起作用，我的意思是文本字段没有焦点： 操作系统：Fedora - Gnome

public class Test {
  public static void main(String[] args) {
    String key = null;
    JTextField txtKey = new JTextField();
    txtKey.addAncestorListener(new RequestFocusListener());
    int answerKey = JOptionPane.showOptionDialog(null, new Object[]{"Please enter the key:", txtKey}, "Title", JOptionPane.OK_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE, null, new Object[]{"OKKK", "CANCELLLL"}, "OKKK");
    if (answerKey == JOptionPane.OK_OPTION && txtKey.getText() != null) {
      key = txtKey.getText();
    }
  }
}

Answer 1

我找到了解决办法！ 非常原始，但有效。

只需通过 java.awt 跳转到该字段。Robot 使用“Tab”键。
我创建了 utils 方法调用“pressTab(..)” 例如：

GuiUtils.pressTab(1);   <------------- // add this method before popup show

int result = JOptionPane.showConfirmDialog(this, inputs, "Text search window", JOptionPane.PLAIN_MESSAGE);
if (result == JOptionPane.OK_OPTION)
{
    
}

如果您应该多次按“Tab”来获取您的组件，您可以使用以下方法：

GUIUtils.pressTab(3);

定义：

public static void pressTab(int amountOfClickes)
{
    SwingUtilities.invokeLater(new Runnable()
    {
        public void run()
        {
            try
            {
                Robot robot = new Robot();
                int i = amountOfClickes;
                while (i-- > 0)
                {
                    robot.keyPress(KeyEvent.VK_TAB);
                    robot.delay(100);
                    robot.keyRelease(KeyEvent.VK_TAB);
                }
            }
            catch (AWTException e)
            {
                System.out.println("Failed to use Robot, got exception: " + e.getMessage());
            }
        }
    });
}

如果您的组件位置是动态的，您可以不受限制地运行 while 循环，但在组件上添加一些焦点侦听器，以便在到达时停止循环。

Answer 2

更好的方法：使用构造函数创建 JOptionPane，覆盖 selectInitialValue 以设置焦点，然后使用 createDialog 构建对话框。

// Replace by the constructor you want
JOptionPane pane = new JOptionPane(panel, JOptionPane.PLAIN_MESSAGE, JOptionPane.OK_CANCEL_OPTION) {
  @Override
  public void selectInitialValue() {
    textArea.requestFocusInWindow();
  }
};

JDialog dialog = pane.createDialog(owner, title);
dialog.setVisible(true);

Answer 3

    public static String getPassword(String title) {
        JPanel panel = new JPanel();
        final JPasswordField passwordField = new JPasswordField(10);
        panel.add(new JLabel("Password"));
        panel.add(passwordField);
        JOptionPane pane = new JOptionPane(panel, JOptionPane.QUESTION_MESSAGE, JOptionPane.OK_CANCEL_OPTION) {
            @Override
            public void selectInitialValue() {
                passwordField.requestFocusInWindow();
            }
        };
        pane.createDialog(null, title).setVisible(true);
        return passwordField.getPassword().length == 0 ? null : new String(passwordField.getPassword());
    }

Answer 4

诀窍是 (a) 在文本组件上使用 AncestorListener 来请求焦点，当焦点再次丢失时（给定默认按钮），在文本组件上使用 FocusListener 再次请求焦点（但之后不要一直要求焦点）：

final JPasswordField accessPassword = new JPasswordField();

accessPassword.addAncestorListener( new AncestorListener()
{
  @Override
  public void ancestorRemoved( final AncestorEvent event )
  {
  }
  @Override
  public void ancestorMoved( final AncestorEvent event )
  {
  }
  @Override
  public void ancestorAdded( final AncestorEvent event )
  {
    // Ask for focus (we'll lose it again)
    accessPassword.requestFocusInWindow();
  }
} );

accessPassword.addFocusListener( new FocusListener()
{
  @Override
  public void focusGained( final FocusEvent e )
  {
  }
  @Override
  public void focusLost( final FocusEvent e )
  {
    if( isFirstTime )
    {
      // When we lose focus, ask for it back but only once
      accessPassword.requestFocusInWindow();
      isFirstTime = false;
    }
  }
  private boolean isFirstTime = true;
} );

Answer 5

我遇到了同样的问题，RequestFocusListener() 在 Linux 上不起作用，在关注 http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5018574 的讨论后，我发现添加一个 invokeLater 暂时修复了它...

public class RequestFocusListener implements AncestorListener
{
public void ancestorAdded(final AncestorEvent e)
{
    final AncestorListener al= this;   
    SwingUtilities.invokeLater(new Runnable(){

        @Override
        public void run() {
            JComponent component = (JComponent)e.getComponent();
            component.requestFocusInWindow();
            component.removeAncestorListener( al );
        }
    });
}

public void ancestorMoved(AncestorEvent e) {}
public void ancestorRemoved(AncestorEvent e) {}
}

Answer 6

Dialog Focus 展示了如何轻松地将焦点设置在模态对话框中的任何组件上。

Answer 7

将 null 作为最后一个参数传递是解决方案。至少它对我有用。

String key = null;
JTextField txtKey = new JTextField();        
int answerKey = JOptionPane.showOptionDialog(this, new Object[] {pleaseEnterTheKey, txtKey}, decryptionKey, JOptionPane.OK_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE, null, new Object[] {okCaption, cancelCaption}, null);        
if (answerKey == JOptionPane.OK_OPTION && txtKey.getText() != null) {
  key = txtKey.getText();
}

但即使是这种解决方案也会带来另一个问题：

Focused 组件和Default 组件是不同的。默认组件或默认按钮是点击ENTER KEY时触发的按钮。最后一个参数定义了默认组件，它也获得焦点，传递null会带来没有默认组件的问题！ 我以这种方式为我的代码解决了这个问题，但我想这不是最佳实践：

String key = null;
    final JTextField txtKey = new JTextField();
    txtKey.addKeyListener(new KeyAdapter() {

      @Override
      public void keyPressed(KeyEvent e) {
        int keyCode = e.getKeyCode();
        if (keyCode == 10) { //enter key
          Container parent = txtKey.getParent();              
          while (!(parent instanceof JOptionPane)) {
            parent = parent.getParent();
          }

          JOptionPane pane = (JOptionPane) parent;
          final JPanel pnlBottom = (JPanel) pane.getComponent(pane.getComponentCount() - 1);
          for (int i = 0; i < pnlBottom.getComponents().length; i++) {
            Component component = pnlBottom.getComponents()[i];
            if (component instanceof JButton) {
              final JButton okButton = ((JButton)component);
              if (okButton.getText().equalsIgnoreCase(okCaption)) {
                ActionListener[] actionListeners = okButton.getActionListeners();
                if (actionListeners.length > 0) {
                  actionListeners[0].actionPerformed(null);
                }
              }
            }
          }
        }
      }

    });

Answer 8

试试这个

String key = null;
JTextField txtKey = new JTextField();
Object[] foo = {pleaseEnterTheKey, txtKey};      
int answerKey = JOptionPane.showOptionDialog(this, foo, decryptionKey, JOptionPane.OK_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE, null, new Object[] {okCaption, cancelCaption}, foo[1]);        
if (answerKey == JOptionPane.OK_OPTION && txtKey.getText() != null) {
  key = txtKey.getText();
}