Как обеспечить, чтобы JPanel сжималась при изменении размера родительского фрейма?

Question

У меня есть панель основных заметок, в которой я хочу сжать ширину, когда размер матрицы jarrame изменяется, но этого не происходит. Я использую вложенные gridbaglayouts.

package com.protocase.notes.views; 

import com.protocase.notes.controller.NotesController; 
import com.protocase.notes.model.Subject; 
import com.protocase.notes.model.Note; 
import com.protocase.notes.model.database.PMSNotesAdapter; 
import java.awt.Color; 
import java.awt.GridBagConstraints; 
import java.awt.GridBagLayout; 
import javax.swing.BorderFactory; 
import javax.swing.JButton; 
import javax.swing.JLabel; 
import javax.swing.JPanel; 
import javax.swing.JScrollPane; 

/** 
* @author DavidH 
*/ 
public class NotesViewer extends JPanel { 
    // <editor-fold defaultstate="collapsed" desc="Attributes"> 

    private Subject subject; 
    private NotesController controller; 

    //</editor-fold> 
    // <editor-fold defaultstate="collapsed" desc="Getters N' Setters"> 
    /** 
    * Gets back the current subject. 
    * @return 
    */ 
    public Subject getSubject() { 
     return subject; 
    } 

    public NotesController getController() { 
     return controller; 
    } 

    public void setController(NotesController controller) { 
     this.controller = controller; 
    } 

    /** 
    * Should clear the panel of the current subject and load the details for 
    * the other object. 
    * @param subject 
    */ 
    public void setSubject(Subject subject) { 
     this.subject = subject; 
    } 
    //</editor-fold> 
    // <editor-fold defaultstate="collapsed" desc="Constructor"> 

    /** 
    * -- Sets up a note viewer with a subject and a controller. Likely this 
    * would be the constructor used if you were passing off from another 
    * NoteViewer or something else that used a notes adapter or controller. 
    * @param subject 
    * @param controller 
    */ 
    public NotesViewer(Subject subject, NotesController controller) { 
     this.subject = subject; 
     this.controller = controller; 
     initComponents(); 
    } 

    /** 
    * -- Sets up a note view with a subject and creates a new controller. This 
    * would be the constructor typically chosen if choosing notes was 
    * infrequent and only one or two notes needs to be displayed. 
    * @param subject 
    */ 
    public NotesViewer(Subject subject) { 
     this(subject, new NotesController(new PMSNotesAdapter())); 
    } 

    /** 
    * -- Sets up a note view without a subject and creates a new controller. 
    *  This would be for a note viewer without any notes, perhaps populating 
    *  as you choose values in another form. 
    * @param subject 
    */ 
    public NotesViewer() { 
     this(null); 
    } 
    //</editor-fold> 
    // <editor-fold defaultstate="collapsed" desc="initComponents()"> 

    /** 
    * Sets up the view for the NotesViewer 
    */ 
    private void initComponents() { 
     // -- Make a new panel for the header 
     JPanel panel = new JPanel(); 

     panel.setLayout(new GridBagLayout()); 
     GridBagConstraints c = new GridBagConstraints(); 


     c.gridx = 0; 
     c.fill = GridBagConstraints.HORIZONTAL; 
     c.gridy = 0; 
     c.weightx = .5; 
     //c.anchor = GridBagConstraints.NORTHWEST; 
     JLabel label = new JLabel("Viewing Notes for [Subject]"); 
     label.setAlignmentX(JLabel.LEFT_ALIGNMENT); 
     label.setBorder(BorderFactory.createLineBorder(Color.YELLOW)); 

     panel.add(label); 

     JButton newNoteButton = new JButton("New"); 
     c = new GridBagConstraints(); 
//  c.fill = GridBagConstraints.HORIZONTAL; 
     c.gridx = 1; 
     c.gridy = 0; 
     c.weightx = .5; 
     c.anchor = GridBagConstraints.EAST; 
     panel.add(newNoteButton, c); 

     // -- NotePanels 
     c = new GridBagConstraints(); 
     c.fill = GridBagConstraints.HORIZONTAL; 
     c.weightx = 1; 
     c.weighty = 1; 
     c.gridx = 0; 
     c.gridwidth = 2; 


     int y = 1; 
     for (Note n : subject.getNotes()) { 
      c.gridy = y++; 
      panel.add(new NotesPanel(n, controller), c); 
     } 


     this.setLayout(new GridBagLayout()); 
     GridBagConstraints pc = new GridBagConstraints(); 
     pc.gridx = 0; 
     pc.gridy = 0; 
     pc.weightx = 1; 
     pc.weighty = 1; 
     pc.fill = GridBagConstraints.BOTH; 

     panel.setBackground(Color.blue); 
     JScrollPane scroll = new JScrollPane(); 
     scroll.setViewportView(panel); 
     //scroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); 
     this.add(scroll, pc); 
     //this.add(panel, pc); 
     // -- Add it all to the layout 
    } 
    //</editor-fold> 
    // <editor-fold defaultstate="collapsed" desc="private methods"> 
    //</editor-fold> 
} 

---

package com.protocase.notes.views; 

import com.protocase.notes.controller.NotesController; 
import com.protocase.notes.model.Note; 
import java.awt.CardLayout; 
import java.awt.Color; 
import java.awt.Component; 
import java.awt.Dimension; 
import java.awt.GridBagConstraints; 
import java.awt.GridBagLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.text.DateFormat; 
import java.text.SimpleDateFormat; 
import javax.swing.BorderFactory; 
import javax.swing.JButton; 
import javax.swing.JLabel; 
import javax.swing.JPanel; 
import javax.swing.JScrollPane; 
import javax.swing.JTextArea; 
import javax.swing.JTextField; 
import javax.swing.border.BevelBorder; 
import javax.swing.border.Border; 
import javax.swing.border.MatteBorder; 

/** 
* @author dah01 
*/ 
public class NotesPanel extends JPanel { 
    // <editor-fold defaultstate="collapsed" desc="Attributes"> 
    private Note note; 
    private NotesController controller; 
    private CardLayout cardLayout; 
    private JTextArea viewTextArea; 
    private JTextArea editTextArea; 
    //</editor-fold> 
    // <editor-fold defaultstate="collapsed" desc="Getters N' Setters"> 

    public NotesController getController() { 
     return controller; 
    } 

    public void setController(NotesController controller) { 
     this.controller = controller; 
    } 

    public Note getNote() { 
     return note; 
    } 

    public void setNote(Note note) { 
     this.note = note; 
    } 
    //</editor-fold> 
    // <editor-fold defaultstate="collapsed" desc="Constructor"> 

    /** 
    * Sets up a note panel that shows everything about the note. 
    * @param note 
    */ 
    public NotesPanel(Note note, NotesController controller) { 

     this.note = note; 
     cardLayout = new CardLayout(); 
     this.setLayout(cardLayout); 


     // -- Setup the layout manager. 
     this.setBackground(new Color(199, 187, 192)); 
     this.setBorder(new BevelBorder(BevelBorder.RAISED)); 



     // -- ViewPanel 
     this.add("ViewPanel", initViewPanel()); 
     this.add("EditPanel", initEditPanel()); 

    } 
    //</editor-fold> 
    // <editor-fold defaultstate="collapsed" desc="EditPanel"> 
    private JPanel initEditPanel() { 
     JPanel editPanel = new JPanel(); 
     editPanel.setLayout(new GridBagLayout()); 
     GridBagConstraints c = new GridBagConstraints(); 

     c.fill = GridBagConstraints.HORIZONTAL; 
     c.gridy = 0; 
     c.weightx = 1; 
     c.weighty = 0.3; 
     editPanel.add(initCreatorLabel(), c); 

     c.gridy++; 
     editPanel.add(initEditTextScroll(), c); 

     c.gridy++; 
     c.anchor = GridBagConstraints.WEST; 
     c.fill = GridBagConstraints.NONE; 
     editPanel.add(initEditorLabel(), c); 

     c.gridx++; 
     c.anchor = GridBagConstraints.EAST; 
     editPanel.add(initSaveButton(), c); 




     return editPanel; 
    } 

    private JScrollPane initEditTextScroll() { 
     this.editTextArea = new JTextArea(note.getContents()); 
     editTextArea.setLineWrap(true); 
     editTextArea.setWrapStyleWord(true); 
     JScrollPane scrollPane = new JScrollPane(editTextArea); 
     scrollPane.setAlignmentX(JScrollPane.LEFT_ALIGNMENT); 
     Border b = scrollPane.getViewportBorder(); 

     MatteBorder mb = BorderFactory.createMatteBorder(2, 2, 2, 2, Color.BLUE); 

     scrollPane.setBorder(mb); 
     return scrollPane; 
    } 

    private JButton initSaveButton() { 
     final CardLayout l = this.cardLayout; 
     final JPanel p = this; 

     final NotesController c = this.controller; 
     final Note n = this.note; 
     final JTextArea noteText = this.viewTextArea; 
     final JTextArea textToSubmit = this.editTextArea; 
     ActionListener al = new ActionListener() { 
      @Override 
      public void actionPerformed(ActionEvent e) { 
       //controller.saveNote(n); 
       noteText.setText(textToSubmit.getText()); 
       l.next(p); 
      } 
     }; 

     JButton saveButton = new JButton("Save"); 
     saveButton.addActionListener(al); 
     saveButton.setPreferredSize(new Dimension(62, 26)); 



     return saveButton; 
    } 

    //</editor-fold> 
    // <editor-fold defaultstate="collapsed" desc="ViewPanel"> 
    private JPanel initViewPanel() { 
     JPanel viewPanel = new JPanel(); 
     viewPanel.setLayout(new GridBagLayout()); 
     GridBagConstraints c = new GridBagConstraints(); 

     c.fill = GridBagConstraints.HORIZONTAL ; 
     c.gridy = 0; 
     c.weightx = 1; 
     c.weighty = 0.3; 
     viewPanel.add(initCreatorLabel(), c); 

     c.gridy++; 

     viewPanel.add(this.initNoteTextArea(), c); 

     c.fill = GridBagConstraints.NONE; 
     c.anchor = GridBagConstraints.WEST; 
     c.gridy++; 
     viewPanel.add(initEditorLabel(), c); 

     c.gridx++; 
     c.anchor = GridBagConstraints.EAST; 
     viewPanel.add(initEditButton(), c); 

     return viewPanel; 
    } 

    private JLabel initCreatorLabel() { 
     DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd"); 
     if (note != null) { 
      String noteBy = "Note by " + note.getCreator(); 

      String noteCreated = formatter.format(note.getDateCreated()); 
      JLabel creatorLabel = new JLabel(noteBy + " @ " + noteCreated); 
      creatorLabel.setAlignmentX(JLabel.LEFT_ALIGNMENT); 
      return creatorLabel; 
     } else { 
      System.out.println("NOTE IS NULL"); 
      return null; 
     } 


    } 

    private JScrollPane initNoteTextArea() { 
     // -- Setup the notes area. 
     this.viewTextArea = new JTextArea(note.getContents()); 
     viewTextArea.setEditable(false); 
     viewTextArea.setLineWrap(true); 
     viewTextArea.setWrapStyleWord(true); 
     JScrollPane scrollPane = new JScrollPane(viewTextArea); 
     scrollPane.setAlignmentX(JScrollPane.LEFT_ALIGNMENT); 

     return scrollPane; 
    } 

    private JLabel initEditorLabel() { 
     // -- Setup the edited by label. 
     JLabel editorLabel = new JLabel(" -- Last edited by " + note.getLastEdited() + " at " + note.getDateModified()); 
     editorLabel.setAlignmentX(Component.LEFT_ALIGNMENT); 
     return editorLabel; 
    } 

    private JButton initEditButton() { 
     final CardLayout l = this.cardLayout; 
     final JPanel p = this; 

     ActionListener ar = new ActionListener() { 

      @Override 
      public void actionPerformed(ActionEvent e) { 
       l.next(p); 
      } 
     }; 

     JButton editButton = new JButton("Edit"); 
     editButton.setPreferredSize(new Dimension(62,26)); 
     editButton.addActionListener(ar); 

     return editButton; 
    } 
    //</editor-fold> 
    // <editor-fold defaultstate="collapsed" desc="Grow Width When Resized"> 

    @Override 
    public Dimension getPreferredSize() { 
     int fw = this.getParent().getSize().width; 
     int fh = super.getPreferredSize().height; 
     return new Dimension(fw,fh); 
    } 
    //</editor-fold> 
} 

Answer 1

Для ручного управления добавить компонент слушателя родительского компонента, как это:

MyParentComponent.addComponentListener(new java.awt.event.ComponentAdapter() { 
    public void componentResized(java.awt.event.ComponentEvent evt) { 
     ComponentResized(evt); 
    } 
}); 

Создать метод «ComponentResized» и изменить размер, чтобы все, что вам нужно, как это :

private void ComponentResized(ComponentEvent evt) 
{ 
    MyChildComponent.setSize(newWidth, newHeight); 
}