使某些面板显示在cardlayout

Question

所以我正在用gui进行研究任务，我在左侧面板上有3个框"输入"，"处理"one_answers"显示"，如果使用CardLayout选择"输入"则第一个面板显示在右侧，如果选择"显示"则显示最后一个面板，但我无法获得"处理"显示在这部分:

public void actionPerformed( ActionEvent event )   {
    // show first card
    if ( event.getSource() == controls[ 0 ] )    
        cardManager.first( deck ); 
    else if ( event.getSource() == controls[ 1 ] )    
        cardManager.show( card2Panel(), "c2");  
    // show previous card
    else if ( event.getSource() == controls[ 2 ] )
        cardManager.last( deck );

完整形式的代码:

import java.awt.*;

进口java.awt.event。;进口javax.swing。,

公共类BookCentre扩展JFrame实现ActionListener {

private CardLayout cardManager;
private JPanel deck;
private JButton controls[];
private String names[] = { "Input", "Processing", "Display"};
public BookCentre(){
    super( "CardLayout" );
    Container container = getContentPane();
    deck = new JPanel();
    cardManager = new CardLayout(); 
    deck.setLayout( cardManager );  
    deck.add( card1Panel(), "c1" );
    deck.add( card2Panel(), "c2" );
    deck.add( card3Panel(), "c3" );
    JPanel buttons = new JPanel();
    buttons.setLayout( new GridLayout( 2, 2 ) );
    controls = new JButton[ names.length ];
    for ( int count = 0; count < controls.length; count++ ) {
        controls[ count ] = new JButton( names[ count ] );
        controls[ count ].addActionListener( this );
        buttons.add( controls[ count ] );
        container.add( buttons, BorderLayout.WEST );
        container.add( deck, BorderLayout.EAST );
        setSize( 450, 200 );
        setVisible( true );}

}

public JPanel card1Panel(){ 
JLabel label1 = new JLabel( "card one",  SwingConstants.CENTER );
JPanel card1 = new JPanel();
card1.add( label1 ); 
return card1;

}

public JPanel card2Panel(){
    JLabel label2 = new JLabel( "card two", SwingConstants.CENTER );
    JPanel card2 = new JPanel();
    card2.setBackground( Color.yellow );
    card2.add( label2 );
    return card2;

}

public JPanel card3Panel(){
    JLabel label3 = new JLabel( "card three" );
    JPanel card3 = new JPanel();
    card3.setLayout( new BorderLayout() );  
    card3.add( new JButton( "North" ), BorderLayout.NORTH);
    card3.add( new JButton( "West" ), BorderLayout.WEST );
    card3.add( new JButton( "East" ), BorderLayout.EAST );
    card3.add( new JButton( "South" ), BorderLayout.SOUTH);
    card3.add( label3, BorderLayout.CENTER );
    return card3;

}

public void actionPerformed( ActionEvent event )   {
    // show first card
    if ( event.getSource() == controls[ 0 ] )    
        cardManager.first( deck ); 
    else if ( event.getSource() == controls[ 1 ] )    
        cardManager.show( card2Panel(), "c2");  
    // show previous card
    else if ( event.getSource() == controls[ 2 ] )
        cardManager.last( deck );           

}

public static void main( String args[] )   {
    BookCentre cardDeckDemo = new BookCentre();
    cardDeckDemo.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );

}}

我可以使用cardManager。第一，下一个，前一个，最后一个。我只希望显示"Processing"面板(所以card2)，而不是用户首先看到，最后看到或循环遍历所有面板。

Answer 1

查看CardLayout的Java Trail。ActionListener中的cardManager.show()调用应该是

cardManager.show( deck, "c2" );

作为第一个参数是带有CardLayout的父容器，而不是您想要显示的组件。