Controlling the scroll pane in JComboBox

Discussion in 'Java' started by Aaron Fude, Jun 10, 2008.

  1. Aaron Fude

    Aaron Fude Guest

    Hi,

    I'm having all sorts of problems controlling dimensions in Swing with
    LayoutManagers. (Is there an article somewhere about this?)

    Here's an example. I have a custom ComboBox that narrows down the
    choices depending on the input. I implement ListCellRenderer, which:
    if there is no input, returns a JLabel; if there is input, it returns
    a panel with three labels with the middle one "highlighting" the
    selection. You can see the demo here:

    file:///C:/pg/InstantDemo/Projects/ComboBox.html

    Question: How come the scroll bars appear for the labels but not for
    the panels?

    The panel uses a BoxLayout.

    If you need more information, I'm happy to provide it.

    Thanks!
    Aaron Fude, Jun 10, 2008
    #1
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  2. Aaron Fude

    Aaron Fude Guest

    Aaron Fude, Jun 10, 2008
    #2
    1. Advertising

  3. On Jun 10, 2:26 pm, Aaron Fude <> wrote:
    > Hi,
    >
    > I'm having all sorts of problems controlling dimensions in Swing with
    > LayoutManagers. (Is there an article somewhere about this?)


    <http://java.sun.com/docs/books/tutorial/uiswing/layout/using.html>

    --
    Andrew T.
    Andrew Thompson, Jun 10, 2008
    #3
  4. Aaron Fude

    Aaron Fude Guest

    Good suggestion, Pete! The code is below.

    I welcome comments about all aspects of my code, but for now I'm
    mostly interested in why there are no scroll bars when there is a
    query and a panel is used for rendering...

    Many thanks in advance,

    Aaron

    package pmg;

    import java.awt.*;

    import javax.swing.*;
    import javax.swing.event.*;

    import java.awt.event.*;
    import java.util.ArrayList;

    public class ChoiceGui extends JComboBox {
    private ArrayList<String> myList = new ArrayList<String>();
    private boolean mySettingItem = false;
    private boolean myRespondingToChangedQuery = false;


    public static void main(String[] args) {

    ArrayList<String> choices = new ArrayList<String>();
    choices.addAll(java.util.Arrays.asList(
    "Hello;Hello, World!;A very looooooooooooooong String;Very
    Slow;Bad dog, bad!".split(";")));

    JFrame frame = new JFrame("Choice");
    frame.getContentPane().add(new ChoiceGui(choices));
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
    }

    public ChoiceGui(ArrayList<String> choices) {

    myList = choices;

    setEditor(new Editor());
    setRenderer(new Renderer3());
    setBackground(Color.getHSBColor(1f/6, .2f, 1f));

    this.setPreferredSize(new Dimension(150, 22));

    for (int s = 0; s < myList.size(); s++)
    this.addItem(myList.get(s));

    this.setSelectedIndex(-1);

    this.setEditable(true); // This is when the first setItem() is
    called!
    }


    public class Editor implements ComboBoxEditor {
    private JTextField myTextField = new JTextField();

    public void addActionListener(ActionListener l)
    { myTextField.addActionListener(l); }
    public void removeActionListener(ActionListener l) { }
    public void setItem(Object item) {
    if (myRespondingToChangedQuery)
    return;

    System.out.println("setItem called!!!");
    mySettingItem = true;
    if (item != null) {
    myTextField.setText(item.toString());
    myTextField.setCaretPosition(0);
    }
    else if (!myRespondingToChangedQuery) // The value of
    SuperChoice changed for a different reason, so the query must be
    reset.
    myTextField.setText("");

    mySettingItem = false;
    }
    public void selectAll() { myTextField.selectAll(); }
    public Object getItem() { return null; }
    public Component getEditorComponent() { return myTextField; }


    public Editor() {
    myTextField.getDocument().addDocumentListener(new
    DocumentListener() {
    public void dodo() {

    javax.swing.SwingUtilities.invokeLater(new Runnable() {
    public void run() {
    myRespondingToChangedQuery = true;

    String q =
    ((JTextField)getEditor().getEditorComponent()).getText();
    removeAllItems();
    for (int i = 0; i < myList.size(); i++)
    if
    (myList.get(i).toUpperCase().contains(q.toUpperCase()))
    addItem(myList.get(i));

    setPopupVisible(true);

    myRespondingToChangedQuery = false;

    }
    });
    }

    public void changedUpdate(DocumentEvent e) {
    if (mySettingItem)
    return;
    dodo();
    }
    public void insertUpdate(DocumentEvent e) {
    if (mySettingItem)
    return;
    dodo();
    }
    public void removeUpdate(DocumentEvent e) {
    if (mySettingItem)
    return;

    dodo();
    }
    });

    }
    }
    class Renderer3 implements ListCellRenderer {
    JPanel panel = new JPanel();
    JLabel label = new JLabel();
    JLabel label1 = new JLabel();
    JLabel label2 = new JLabel();
    JLabel label3 = new JLabel();

    public Renderer3() {
    panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));

    panel.add(label1);
    panel.add(label2);
    panel.add(label3);

    panel.setOpaque(true);
    panel.setBackground(Color.RED);
    Font font = label1.getFont();
    label.setFont(new Font(font.getName(), Font.PLAIN,
    font.getSize()-2));
    label1.setFont(new Font(font.getName(), Font.PLAIN,
    font.getSize()));
    label2.setFont(new Font(font.getName(), Font.BOLD,
    font.getSize()));
    label3.setFont(new Font(font.getName(), Font.PLAIN,
    font.getSize()));

    label.setOpaque(true);
    panel.setBackground(Color.getHSBColor(1f/6, .2f, 1f));
    }

    public Component getListCellRendererComponent(JList list, Object
    value, int index, boolean isSelected, boolean cellHasFocus) {
    String str = (value!=null)?value.toString():"null";
    String q =
    ((JTextField)getEditor().getEditorComponent()).getText();
    if (q.length() != 0 &&
    str.toUpperCase().indexOf(q.toUpperCase()) != -1) {
    int start = str.toUpperCase().indexOf(q.toUpperCase());
    label1.setText(str.substring(0, start));
    label2.setText(str.substring(start, start + q.length()));
    label3.setText(str.substring(start + q.length()));
    panel.setBackground(isSelected?
    list.getSelectionBackground():list.getBackground());
    panel.setForeground(isSelected?
    list.getSelectionForeground():list.getForeground());

    return panel;
    }
    else {
    Font font = label.getFont();
    label.setFont(new Font("Dialog", Font.PLAIN, 12));
    label.setBackground(isSelected?
    list.getSelectionBackground():list.getBackground());
    label.setForeground(isSelected?
    list.getSelectionForeground():list.getForeground());
    label.setText(" " + str);
    return label;
    }

    }
    }

    }
    Aaron Fude, Jun 10, 2008
    #4
  5. Aaron Fude

    Guest

    Use the setUI() method
    and an extended BasicComboBoxUI class.

    also import javax.swing.plaf.basic.*;

    regards

    Chinthaka Weerasinghe - Your friendly java tutor




    package pmg;

    import java.awt.*;

    import javax.swing.*;
    import javax.swing.event.*;

    import java.awt.event.*;
    import java.util.ArrayList;

    import javax.swing.plaf.basic.*;

    public class ChoiceGui extends JComboBox {
    private ArrayList<String> myList = new ArrayList<String>();
    private boolean mySettingItem = false;
    private boolean myRespondingToChangedQuery = false;

    public static void main(String[] args) {

    ArrayList<String> choices = new ArrayList<String>();
    choices.addAll(java.util.Arrays.asList("Hello;Hello, World!;A very
    looooooooooooooong String;Very Slow;Bad dog, bad!".split(";")));

    JFrame frame = new JFrame("Choice");
    frame.getContentPane().add(new ChoiceGui(choices));
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
    }

    public ChoiceGui(ArrayList<String> choices) {

    myList = choices;

    setEditor(new Editor());
    setRenderer(new Renderer3());
    setBackground(Color.getHSBColor(1f/6, .2f, 1f));

    this.setPreferredSize(new Dimension(150, 22));

    for (int s = 0; s < myList.size(); s++)
    this.addItem(myList.get(s));

    this.setSelectedIndex(-1);

    this.setEditable(true); // This is when the first setItem() is
    called!
    setUI(new myComboUI());
    }

    public class myComboUI extends BasicComboBoxUI{
    protected ComboPopup createPopup(){
    BasicComboPopup popup = new BasicComboPopup(comboBox){
    protected JScrollPane createScroller() {
    return new JScrollPane( list,
    ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
    ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED );
    }// end of method createScroller
    };
    return popup;
    }// end of method createPopup
    }// end of inner class myComboUI



    public class Editor implements ComboBoxEditor {
    private JTextField myTextField = new JTextField();

    public void addActionListener(ActionListener l)
    { myTextField.addActionListener(l); }
    public void removeActionListener(ActionListener l) { }
    public void setItem(Object item) {
    if (myRespondingToChangedQuery)
    return;

    System.out.println("setItem called!!!");
    mySettingItem = true;
    if (item != null) {
    myTextField.setText(item.toString());
    myTextField.setCaretPosition(0);
    }
    else if (!myRespondingToChangedQuery) // The value of SuperChoice
    changed
    // for a different reason, so the
    // query must be reset.
    myTextField.setText("");

    mySettingItem = false;
    }
    public void selectAll() { myTextField.selectAll(); }
    public Object getItem() { return null; }
    public Component getEditorComponent() { return myTextField; }

    public Editor() {
    myTextField.getDocument().addDocumentListener(new
    DocumentListener() {
    public void dodo() {

    javax.swing.SwingUtilities.invokeLater(new Runnable() {
    public void run() {
    myRespondingToChangedQuery = true;

    String q =
    ((JTextField)getEditor().getEditorComponent()).getText();
    removeAllItems();
    for (int i = 0; i < myList.size(); i++)
    if (myList.get(i).toUpperCase().contains(q.toUpperCase()))
    addItem(myList.get(i));

    setPopupVisible(true);

    myRespondingToChangedQuery = false;

    }
    });
    }

    public void changedUpdate(DocumentEvent e) {
    if (mySettingItem)
    return;
    dodo();
    }
    public void insertUpdate(DocumentEvent e) {
    if (mySettingItem)
    return;
    dodo();
    }
    public void removeUpdate(DocumentEvent e) {
    if (mySettingItem)
    return;

    dodo();
    }
    });

    }
    }
    class Renderer3 implements ListCellRenderer {
    JPanel panel = new JPanel();
    JLabel label = new JLabel();
    JLabel label1 = new JLabel();
    JLabel label2 = new JLabel();
    JLabel label3 = new JLabel();

    public Renderer3() {
    panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));

    panel.add(label1);
    panel.add(label2);
    panel.add(label3);

    panel.setOpaque(true);
    panel.setBackground(Color.RED);
    Font font = label1.getFont();
    label.setFont(new Font(font.getName(),
    Font.PLAIN,font.getSize()-2));
    label1.setFont(new Font(font.getName(),
    Font.PLAIN,font.getSize()));
    label2.setFont(new Font(font.getName(), Font.BOLD,font.getSize()));
    label3.setFont(new Font(font.getName(),
    Font.PLAIN,font.getSize()));
    label.setOpaque(true);
    panel.setBackground(Color.getHSBColor(1f/6, .2f, 1f));
    }

    public Component getListCellRendererComponent(JList list, Object
    value, int index, boolean isSelected, boolean cellHasFocus) {
    String str = (value!=null)?value.toString():"null";
    String q =
    ((JTextField)getEditor().getEditorComponent()).getText();
    if (q.length() != 0 && str.toUpperCase().indexOf(q.toUpperCase()) !
    = -1) {
    int start = str.toUpperCase().indexOf(q.toUpperCase());
    label1.setText(str.substring(0, start));
    label2.setText(str.substring(start, start + q.length()));
    label3.setText(str.substring(start + q.length()));
    panel.setBackground(isSelected?
    list.getSelectionBackground():list.getBackground());
    panel.setForeground(isSelected?
    list.getSelectionForeground():list.getForeground());

    return panel;
    }
    else {
    Font font = label.getFont();
    label.setFont(new Font("Dialog", Font.PLAIN, 12));
    label.setBackground(isSelected?
    list.getSelectionBackground():list.getBackground());
    label.setForeground(isSelected?
    list.getSelectionForeground():list.getForeground());
    label.setText(" " + str);
    return label;
    }
    }
    }
    }

    On Jun 10, 9:26 am, Aaron Fude <> wrote:
    > Hi,
    >
    > I'm having all sorts of problems controlling dimensions in Swing with
    > LayoutManagers. (Is there an article somewhere about this?)
    >
    , Jun 11, 2008
    #5
  6. Aaron Fude

    Aaron Fude Guest

    Thanks!

    But can you explain why it makes a difference?
    Why would, in the original solution, the scroll bars not appear for
    JPanels but appear for the labels?

    Also, how do I control the numbers of rows that is shown in the popup?

    Thanks!
    Aaron Fude, Jun 12, 2008
    #6
  7. On Jun 10, 2:26=A0pm, Aaron Fude <> wrote:
    > Hi,
    >
    > I'm having all sorts of problems controlling dimensions in Swing with
    > LayoutManagers. (Is there an article somewhere about this?)



    --
    Patty T.


    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    "This is Preservation Month.
    I appreciate preservation.
    It's what you do when you run for president.
    You gotta preserve."

    --- Adolph Bush,
    Speaking during "Perseverance Month"
    at Fairgrounds Elementary School in Nashua, N.H.
    As quoted in the Los Angeles Times, Jan. 28, 2000
    Andrew Thompson, Jun 29, 2008
    #7
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