介绍

CardLayout类排列一张牌的容器中的每个组件。只有一张卡是可见的时间，与容器作为将整叠卡片。

类的声明

以下是声明的java.awt.CardLayout类：

public class CardLayout
   extends Object
      implements LayoutManager2, Serializable

类的构造函数

S.N.	构造函数与说明
1	CardLayout()  Creates a new card layout with gaps of size zero.
2	CardLayout(int hgap, int vgap)  Creates a new card layout with the specified horizontal and vertical gaps.

类方法

S.N.	方法和说明
1	void addLayoutComponent(Component comp, Object constraints)  Adds the specified component to this card layout's internal table of names.
2	void addLayoutComponent(String name, Component comp)  If the layout manager uses a per-component string, adds the component comp to the layout, associating it with the string specified by name.
3	void first(Container parent)  Flips to the first card of the container.
4	int getHgap()  Gets the horizontal gap between components.
5	float getLayoutAlignmentX(Container parent)  Returns the alignment along the x axis.
6	float getLayoutAlignmentY(Container parent)  Returns the alignment along the y axis.
7	int getVgap()  Gets the vertical gap between components.
8	void invalidateLayout(Container target)  Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
9	void last(Container parent)  Flips to the last card of the container.
10	void layoutContainer(Container parent)  Lays out the specified container using this card layout.
11	Dimension maximumLayoutSize(Container target)  Returns the maximum dimensions for this layout given the components in the specified target container.
12	Dimension minimumLayoutSize(Container parent)  Calculates the minimum size for the specified panel.
13	void next(Container parent)  Flips to the next card of the specified container.
14	Dimension preferredLayoutSize(Container parent)  Determines the preferred size of the container argument using this card layout.
15	void previous(Container parent)  Flips to the previous card of the specified container.
16	void removeLayoutComponent(Component comp)  Removes the specified component from the layout.
17	void setHgap(int hgap)  Sets the horizontal gap between components.
18	void setVgap(int vgap)  Sets the vertical gap between components.
19	void show(Container parent, String name)  Flips to the component that was added to this layout with the specified name, using addLayoutComponent.
20	String toString()  Returns a string representation of the state of this card layout.

继承的方法

这个类继承的方法从以下类：

• java.lang.Object

CardLayout 实例

选择使用任何编辑器创建以下java程序 D:/ > AWT > com > yiibai > gui >

AwtLayoutDemo.java

package com.yiibai.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtLayoutDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;
   private Label msglabel;

   public AwtLayoutDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtLayoutDemo  awtLayoutDemo = new AwtLayoutDemo();  
      awtLayoutDemo.showCardLayoutDemo();       
   }
      
   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      msglabel = new Label();
      msglabel.setAlignment(Label.CENTER);
      msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showCardLayoutDemo(){
      headerLabel.setText("Layout in action: CardLayout");      

      final Panel panel = new Panel();
      panel.setBackground(Color.CYAN);
      panel.setSize(300,300);

      CardLayout layout = new CardLayout();
      layout.setHgap(10);
      layout.setVgap(10);
      panel.setLayout(layout);        

      Panel buttonPanel = new Panel(new FlowLayout());

      buttonPanel.add(new Button("OK"));
      buttonPanel.add(new Button("Cancel"));    

      Panel textBoxPanel = new Panel(new FlowLayout());

      textBoxPanel.add(new Label("Name:"));
      textBoxPanel.add(new TextField(20));

      panel.add("Button", buttonPanel);
      panel.add("Text", textBoxPanel);

      Choice choice = new Choice();
      choice.add("Button");
      choice.add("Text");

      choice.addItemListener(new ItemListener() {
         public void itemStateChanged(ItemEvent e) {
            CardLayout cardLayout = (CardLayout)(panel.getLayout());
            cardLayout.show(panel, (String)e.getItem());
         }
      });
      controlPanel.add(choice);
      controlPanel.add(panel);

      mainFrame.setVisible(true);  
   }
}

编译程序，使用命令提示符。进入到D:/> AWT，然后键入以下命令。

D:AWT>javac comyiibaiguiAwtlayoutDemo.java

如果没有错误出现，这意味着编译成功。使用下面的命令来运行程序。

D:AWT>java com.yiibai.gui.AwtlayoutDemo

验证下面的输出