在調用setComponentAt（）後無法將面板添加到jtabbed窗格（）

Question

我添加了一個名爲MyEditorPanel的自定義面板，它將JPanel擴展到JTabbedPanel，並且希望每個選項卡上都有一個關閉按鈕，以便我使用以下代碼並使用ButtonTabbedComponent.java從ButtonTabbedComponent.java

public void addTab(String name, String desc) { 
    MyEditorPane textEditorPane = new MyEditorPane(this, name, desc); 
    this.addTab(name, normal, textEditorPane, desc); 
    int i = this.getComponentCount() - 1; 
    textEditorPane.setTabCount(i); 
    this.setTabComponentAt(i, new ButtonTabComponent(this, normal, normalFont)); 
} 

，但我想保存MyEditorPane文本關閉我怎樣才能得到它MyEditorPane正在將關閉在關閉之前單擊

當我得到JTabbedPane的組件的名稱類沒有MyEditorPane類對象

方法

@Override 
public void remove(int index) { 

Component component = this.getTabComponentAt(index); 
if (component instanceof ButtonTabComponent) { 
    ButtonTabComponent tab = (ButtonTabComponent) component; 
    System.out.println("remove method called if : " + tab.getComponentCount()); 
    component = tab.getComponent(0); 
    System.out.println("remove method called if : " + component.getClass().getName()); 

    component = tab.getComponent(1); 
    System.out.println("remove method called if : " + component.getClass().getName()); 
    JPanel pane = (JPanel) component; 
    Component[] components = pane.getComponents(); 
    for (int i = 0, l = components.length; i < l; i++) { 
      System.out.println("remove method called for : " + components[i].getClass().getName());     
    } 
    super.remove(index); 
} 
} 

輸出刪除

remove method called if : 2 
remove method called if : javax.swing.JLabel 
remove method called if : javax.swing.JPanel 
remove method called for : pkginterface.ButtonTabComponent$1 
remove method called for : pkginterface.ButtonTabComponent$TabButton 

Answer 1

因此，基於從How to Use Tabbed Panes的例子，你可以使用類似...

public void actionPerformed(ActionEvent e) { 
    int i = pane.indexOfTabComponent(ButtonTabComponent.this); 
    if (i != -1) { 
     Component comp = pane.getComponentAt(i); 
     if (comp instanceof JLabel) { 
      JLabel label = (JLabel) comp; 
      System.out.println("Label text = " + label.getText()); 
      switch (JOptionPane.showConfirmDialog(this, "Are you sure you want to close the \"" + pane.getTitleAt(i) + "\" tab?", "Close", JOptionPane.OK_CANCEL_OPTION)) { 
       case JOptionPane.OK_OPTION: 
        pane.remove(i); 
        break; 
      } 
     } 
    } 
} 

這可以讓你確定哪些是製表已關閉，找到用作選項卡視圖的組件，詢問用戶是否要關閉此特定選項卡並根據其反饋採取適當的操作

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.ActionListener; 
import java.awt.event.ActionEvent; 
import java.awt.event.InputEvent; 
import java.awt.event.KeyEvent; 
import java.awt.event.MouseAdapter; 
import java.awt.event.MouseEvent; 
import java.awt.event.MouseListener; 
import javax.swing.plaf.basic.BasicButtonUI; 

public class TabComponentsDemo extends JFrame { 

    private final int tabNumber = 5; 
    private final JTabbedPane pane = new JTabbedPane(); 
    private JMenuItem tabComponentsItem; 
    private JMenuItem scrollLayoutItem; 

    public static void main(String[] args) { 
     //Schedule a job for the event dispatch thread: 
     //creating and showing this application's GUI. 
     SwingUtilities.invokeLater(new Runnable() { 
      public void run() { 
       try { 
        //Turn off metal's use of bold fonts 
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); 
       } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { 
        ex.printStackTrace(); 
       } 
       new TabComponentsDemo("TabComponentsDemo").runTest(); 
      } 
     }); 
    } 

    public TabComponentsDemo(String title) { 
     super(title); 
     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     initMenu(); 
     add(pane); 
    } 

    public void runTest() { 
     pane.removeAll(); 
     for (int i = 0; i < tabNumber; i++) { 
      String title = "Tab " + i; 
      pane.add(title, new JLabel(title)); 
      initTabComponent(i); 
     } 
     tabComponentsItem.setSelected(true); 
     pane.setTabLayoutPolicy(JTabbedPane.WRAP_TAB_LAYOUT); 
     scrollLayoutItem.setSelected(false); 
     setSize(new Dimension(400, 200)); 
     setLocationRelativeTo(null); 
     setVisible(true); 
    } 

    private void initTabComponent(int i) { 
     pane.setTabComponentAt(i, 
       new ButtonTabComponent(pane)); 
    } 

    //Setting menu 
    private void initMenu() { 
     JMenuBar menuBar = new JMenuBar(); 
     //create Options menu 
     tabComponentsItem = new JCheckBoxMenuItem("Use TabComponents", true); 
     tabComponentsItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_T, InputEvent.ALT_MASK)); 
     tabComponentsItem.addActionListener(new ActionListener() { 
      public void actionPerformed(ActionEvent e) { 
       for (int i = 0; i < pane.getTabCount(); i++) { 
        if (tabComponentsItem.isSelected()) { 
         initTabComponent(i); 
        } else { 
         pane.setTabComponentAt(i, null); 
        } 
       } 
      } 
     }); 
     scrollLayoutItem = new JCheckBoxMenuItem("Set ScrollLayout"); 
     scrollLayoutItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S, InputEvent.ALT_MASK)); 
     scrollLayoutItem.addActionListener(new ActionListener() { 
      public void actionPerformed(ActionEvent e) { 
       if (pane.getTabLayoutPolicy() == JTabbedPane.WRAP_TAB_LAYOUT) { 
        pane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT); 
       } else { 
        pane.setTabLayoutPolicy(JTabbedPane.WRAP_TAB_LAYOUT); 
       } 
      } 
     }); 
     JMenuItem resetItem = new JMenuItem("Reset JTabbedPane"); 
     resetItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_R, InputEvent.ALT_MASK)); 
     resetItem.addActionListener(new ActionListener() { 
      public void actionPerformed(ActionEvent e) { 
       runTest(); 
      } 
     }); 

     JMenu optionsMenu = new JMenu("Options"); 
     optionsMenu.add(tabComponentsItem); 
     optionsMenu.add(scrollLayoutItem); 
     optionsMenu.add(resetItem); 
     menuBar.add(optionsMenu); 
     setJMenuBar(menuBar); 
    } 

    public static class ButtonTabComponent extends JPanel { 

     private final JTabbedPane pane; 

     public ButtonTabComponent(final JTabbedPane pane) { 
      //unset default FlowLayout' gaps 
      super(new FlowLayout(FlowLayout.LEFT, 0, 0)); 
      if (pane == null) { 
       throw new NullPointerException("TabbedPane is null"); 
      } 
      this.pane = pane; 
      setOpaque(false); 

      //make JLabel read titles from JTabbedPane 
      JLabel label = new JLabel() { 
       public String getText() { 
        int i = pane.indexOfTabComponent(ButtonTabComponent.this); 
        if (i != -1) { 
         return pane.getTitleAt(i); 
        } 
        return null; 
       } 
      }; 

      add(label); 
      //add more space between the label and the button 
      label.setBorder(BorderFactory.createEmptyBorder(0, 0, 0, 5)); 
      //tab button 
      JButton button = new TabButton(); 
      add(button); 
      //add more space to the top of the component 
      setBorder(BorderFactory.createEmptyBorder(2, 0, 0, 0)); 
     } 

     private class TabButton extends JButton implements ActionListener { 

      public TabButton() { 
       int size = 17; 
       setPreferredSize(new Dimension(size, size)); 
       setToolTipText("close this tab"); 
       //Make the button looks the same for all Laf's 
       setUI(new BasicButtonUI()); 
       //Make it transparent 
       setContentAreaFilled(false); 
       //No need to be focusable 
       setFocusable(false); 
       setBorder(BorderFactory.createEtchedBorder()); 
       setBorderPainted(false); 
       //Making nice rollover effect 
       //we use the same listener for all buttons 
       addMouseListener(buttonMouseListener); 
       setRolloverEnabled(true); 
       //Close the proper tab by clicking the button 
       addActionListener(this); 
      } 

      public void actionPerformed(ActionEvent e) { 
       int i = pane.indexOfTabComponent(ButtonTabComponent.this); 
       if (i != -1) { 
        Component comp = pane.getComponentAt(i); 
        if (comp instanceof JLabel) { 
         JLabel label = (JLabel) comp; 
         System.out.println("Label text = " + label.getText()); 
         switch (JOptionPane.showConfirmDialog(this, "Are you sure you want to close the \"" + pane.getTitleAt(i) + "\" tab?", "Close", JOptionPane.OK_CANCEL_OPTION)) { 
          case JOptionPane.OK_OPTION: 
           pane.remove(i); 
           break; 
         } 
        } 
       } 
      } 

      //we don't want to update UI for this button 
      public void updateUI() { 
      } 

      //paint the cross 
      protected void paintComponent(Graphics g) { 
       super.paintComponent(g); 
       Graphics2D g2 = (Graphics2D) g.create(); 
       //shift the image for pressed buttons 
       if (getModel().isPressed()) { 
        g2.translate(1, 1); 
       } 
       g2.setStroke(new BasicStroke(2)); 
       g2.setColor(Color.BLACK); 
       if (getModel().isRollover()) { 
        g2.setColor(Color.MAGENTA); 
       } 
       int delta = 6; 
       g2.drawLine(delta, delta, getWidth() - delta - 1, getHeight() - delta - 1); 
       g2.drawLine(getWidth() - delta - 1, delta, delta, getHeight() - delta - 1); 
       g2.dispose(); 
      } 
     } 

     private final static MouseListener buttonMouseListener = new MouseAdapter() { 
      public void mouseEntered(MouseEvent e) { 
       Component component = e.getComponent(); 
       if (component instanceof AbstractButton) { 
        AbstractButton button = (AbstractButton) component; 
        button.setBorderPainted(true); 
       } 
      } 

      public void mouseExited(MouseEvent e) { 
       Component component = e.getComponent(); 
       if (component instanceof AbstractButton) { 
        AbstractButton button = (AbstractButton) component; 
        button.setBorderPainted(false); 
       } 
      } 
     }; 
    } 
}