Focusing a JTextArea in a JTabbedPane

Question

I'm programming a chat client in Java, where I'd like to have one single JDialog for all open chats. So I decided to work with a JTabbedPane where a tab represents a single chat.

I put a JPanel into every tab, which simply contains a JTextPane for the message history and a JTextArea where users input their messages.

For a better usability I implemented a feature that focuses the JTextArea when

a new ChatTab is opened
the user changes between the ChatTabs (the ChangeListener of the JTabbedPane fires)

I have a class ChatWindow, which extends JDialog and displays the JTabbedPane. This is where I implemented the ChangeListener.

private JTabbedPane chatTabPane;
private List<ChatTab> chatTabs;

public ChatWindow() {
    chatTabs = new ArrayList<ChatTab>();

    JPanel chatWindowPanel = new JPanel(new BorderLayout());

    chatTabPane = new JTabbedPane(JTabbedPane.TOP);
    chatWindowPanel.add(chatTabPane);

    this.add(chatWindowPanel, BorderLayout.CENTER);

    chatTabPane.addChangeListener(new ChangeListener() {

        @Override
        public void stateChanged(ChangeEvent arg0) {
            focusInputField();
        }
    });
}

public ChatTab addChatTab(Contact contact) {
    ChatTab newChatTab = new ChatTab();
    chatTabs.add(newChatTab);
    chatTabPane.addTab(contact.toString(), null, newChatTab.getPanel());
    return newChatTab;
}

public void focusInputField() {
    for (ChatTab chatTab : chatTabs) {
        if(chatTab.getPanel() == chatTabPane.getSelectedComponent()) {
            chatTab.focusInputField();
        }
    }
}

public JTabbedPane getChatTabs() {
    return chatTabPane;
}
}

The method focusInputField() in the class ChatTab simply looks like this:

public void focusInputField() {
    inputField.requestFocusInWindow();
    inputField.requestFocus();
}

Okay, that's for the focus when the tab is changed. Beside that, I have also implemented that the JTextArea is focused when a new chat tab is created. That is handled in the class ChatWindowController. There is a method setChatVisible() that I call when I add a new tab to the ChatWindow class:

public void setChatVisible() {
    if(!chatWindow.isVisible()) {
        chatWindow.setVisible(true);

        chatWindow.focusInputField();
    }
}

So here is my problem: The focus works when I open a new chattab. In most cases it also works when the user changes the tabs, BUT it does not focus when I opened more than one new chat tab and switch between the tabs FOR THE FIRST TIME. The JTextArea of the tab where I switched to does not focus. However, when I switch again it works all the time.

Does anyone know what the problem could be? I'm really out of ideas.

score 4 · Accepted Answer · edited May 23 '17 at 12:18

4

Intermittent failure may result from incorrect synchronization. Several thing should be examined critically:

Verify that you construct all GUI elements on the event dispatch thread (EDT).
As you are surely using multiple threads, verify that all updates occur on the EDT, for example.
You can use invokeLater() to order events on the EDT, as shown here.
Prefer requestFocusInWindow() over requestFocus(), but don't use both.

edited May 23 '17 at 12:18

Community

1
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answered Feb 17 '13 at 16:27

trashgod

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Thank you so much! I didn't consider that the EDT could be the problem. Calling the focusInputField() method in the ChatTab class with EventQueue.invokeLater() solved my problem. – Cosmo Jasra Feb 17 '13 at 17:36

Focusing a JTextArea in a JTabbedPane

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