CardLayout示例程序

缺乏、安全感 2022-12-07 12:09 152阅读 0赞

The following is an example of the [Java code][] you can use to show the `CardLayout` layout manager in action.

以下是可用于显示`CardLayout`布局管理器的[Java代码][Java code]示例。

## Java代码 **(** Java Code **)** ##

The `JFrame` uses a BorderLayout to position two `JPanels`, one above the other. The top panel uses the FlowLayout to show a "Switch Card" button which controls which card is show in the bottom panel. The bottom panel uses the `CardLayout` to position two `JPanels`. The `JPanel` on show is determined by the `CardLayout` (which is changed to the next card by pressing the "Switch Card" button).

`JFrame`使用BorderLayout `JPanels`两个`JPanels` ，一个`JPanels`在另一个之上。 顶部面板使用FlowLayout显示“切换卡”按钮，该按钮控制在底部面板中显示哪个卡。 底部面板使用`CardLayout`两个`JPanels` 。 所显示的`JPanel`由`CardLayout` (通过单击“切换卡”按钮更改为下一张卡)确定。

//Imports are listed in full to show what's being used
    //could just import javax.swing.* and java.awt.* etc..
    import java.awt.EventQueue;
    import java.awt.BorderLayout;
    import java.awt.CardLayout;
    import java.awt.Color;
    import javax.swing.BorderFactory;
    import javax.swing.border.Border;
    import javax.swing.JFrame;
    import javax.swing.JPanel;
    import javax.swing.JComboBox;
    import javax.swing.JButton;
    import javax.swing.JLabel;
    import javax.swing.SwingConstants;
    import java.awt.Container;
    import java.awt.event.ActionListener;
    import java.awt.event.ActionEvent;
    public class CardLayoutExample {
    JFrame guiFrame;
    CardLayout cards;
    JPanel cardPanel;
    public static void main(String[] args) {
    //Use the event dispatch thread for Swing components
    EventQueue.invokeLater(new Runnable()
    {
    @Override
    public void run()
    {
    new CardLayoutExample();
    }
    });
    }
    public CardLayoutExample()
    {
    guiFrame = new JFrame();
    //make sure the program exits when the frame closes
    guiFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    guiFrame.setTitle("CardLayout Example");
    guiFrame.setSize(400,300);
    //This will center the JFrame in the middle of the screen
    guiFrame.setLocationRelativeTo(null);
    guiFrame.setLayout(new BorderLayout());
    //creating a border to highlight the JPanel areas
    Border outline = BorderFactory.createLineBorder(Color.black);
    JPanel tabsPanel = new JPanel();
    tabsPanel.setBorder(outline);
    JButton switchCards = new JButton("Switch Card");
    switchCards.setActionCommand("Switch Card");
    switchCards.addActionListener(new ActionListener()
    {
    @Override
    public void actionPerformed(ActionEvent event)
    {
    cards.next(cardPanel);
    }
    });
    tabsPanel.add(switchCards);
    guiFrame.add(tabsPanel,BorderLayout.NORTH);
    cards = new CardLayout();
    cardPanel = new JPanel();
    cardPanel.setLayout(cards);
    cards.show(cardPanel, "Fruits");
    JPanel firstCard = new JPanel();
    firstCard.setBackground(Color.GREEN);
    addButton(firstCard, "APPLES");
    addButton(firstCard, "ORANGES");
    addButton(firstCard, "BANANAS");
    JPanel secondCard = new JPanel();
    secondCard.setBackground(Color.BLUE);
    addButton(secondCard, "LEEKS");
    addButton(secondCard, "TOMATOES");
    addButton(secondCard, "PEAS");
    cardPanel.add(firstCard, "Fruits");
    cardPanel.add(secondCard, "Veggies");
    guiFrame.add(tabsPanel,BorderLayout.NORTH);
    guiFrame.add(cardPanel,BorderLayout.CENTER);
    guiFrame.setVisible(true);
    }
    //All the buttons are following the same pattern
    //so create them all in one place.
    private void addButton(Container parent, String name)
    {
    JButton but = new JButton(name);
    but.setActionCommand(name);
    parent.add(but);
    }
    }

## 附加信息 **(** Additional Information **)** ##

The article that goes with this example is Using the CardLayout. For more information on other layout managers, have a look at [an Overview of Layout Managers][].

此示例附带的文章是使用CardLayout。 有关其他布局管理器的更多信息，看看[布局管理器的概述][an Overview of Layout Managers] 。

> 翻译自: [https://www.thoughtco.com/cardlayout-example-program-2033962][https_www.thoughtco.com_cardlayout-example-program-2033962]

[Java code]: https://www.thoughtco.com/creating-your-first-java-program-2034124
[an Overview of Layout Managers]: https://www.thoughtco.com/gridpane-overview-2033946
[https_www.thoughtco.com_cardlayout-example-program-2033962]: https://www.thoughtco.com/cardlayout-example-program-2033962