Java AWT | CardLayout 类
CardLayout 类以一次只能看到一个组件的方式管理组件。它将每个组件视为容器中的一张卡片。一次只能看到一张卡片，容器充当一叠卡片。添加到卡片布局对象的第一个组件是首次显示容器时的可见组件。
施工人员:
- 卡片布局():用于创建一个间隙大小为零的新卡片布局。
- 卡片布局(int horizontalgap，int verticalgap): 用于创建具有指定水平和垂直间隙的新卡片布局类。
常用方法:
- getLayoutAlignmentX(容器父级):返回沿 x 轴的对齐方式。
- getLayoutAlignmentY(容器父级):返回沿 y 轴的对齐方式。
- getVgap(): 用于获取组件之间的垂直间隙。
- 添加组件(组件 cm，对象 cn): 用于将指定的组件添加到该卡布局的内部名称表中。
- getHgap(): 用于获取组件之间的水平间隙。
- toString(): 返回此卡片布局状态的字符串表示。
- 移除布局组件(组件 cm): 用于从布局中移除指定的组件。
下面的程序说明了卡片布局类:
- 程序 1: 在下面的程序中，我们在一个 JFrame 中安排了几个 JLabel 组件，其实例类为“ Cardlayout ”。我们创建 3 个名为“ bt1 ”、“ bt2 ”、“ bt3 ”的【JButton】组件，然后使用 add() 方法将其添加到 JFrame 中。我们通过设置大小()和设置可见()的方法设置框架的大小和可见性。布局通过方法设置布局()方法设置。
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to illustrate the CardLayout Class
import java.awt.*;
import java.awt.event.*;
import javax.swing.JFrame;
import javax.swing.*;
// class extends JFrame and implements actionlistener
public class Cardlayout extends JFrame implements ActionListener {
// Declaration of objects of CardLayout class.
CardLayout card;
// Declaration of objects of JButton class.
JButton b1, b2, b3;
// Declaration of objects
// of Container class.
Container c;
Cardlayout()
{
// to get the content
c = getContentPane();
// Initialization of object "card"
// of CardLayout class with 40
// horizontal space and 30 vertical space .
card = new CardLayout(40, 30);
// set the layout
c.setLayout(card);
// Initialization of object "b1" of JButton class.
b1 = new JButton("GEEKS");
// Initialization of object "b2" of JButton class.
b2 = new JButton("FOR");
// Initialization of object "b3" of JButton class.
b3 = new JButton("GEEKS");
// this Keyword refers to current object.
// Adding Jbutton "b1" on JFrame using ActionListener.
b1.addActionListener(this);
// Adding Jbutton "b2" on JFrame using ActionListener.
b2.addActionListener(this);
// Adding Jbutton "b3" on JFrame using ActionListener.
b3.addActionListener(this);
// Adding the JButton "b1"
c.add("a", b1);
// Adding the JButton "b2"
c.add("b", b2);
// Adding the JButton "b1"
c.add("c", b3);
}
public void actionPerformed(ActionEvent e)
{
// call the next card
card.next(c);
}
// Main Method
public static void main(String[] args)
{
// Creating Object of CardLayout class.
Cardlayout cl = new Cardlayout();
// Function to set size of JFrame.
cl.setSize(400, 400);
// Function to set visibility of JFrame.
cl.setVisible(true);
// Function to set default operation of JFrame.
cl.setDefaultCloseOperation(EXIT_ON_CLOSE);
}
}
输出:
[https://media.geeksforgeeks.org/wp-content/uploads/CardLayout-1.mp4](https://media.geeksforgeeks.org/wp-content/uploads/CardLayout-1.mp4)- 程序 2: 在下面的程序中，我们正在一个 JFrame 中排列 4 个 JLabel 组件，其类为“cardlayoutemo”。我们创建了名为“ firstbtn ”、“ nextbtn ”、“ previousbtn ”、“ lastbtn ”的 4 个 JLabel 名为“ jl1 ”、“ jl2 ”、“JL 3”的组件这里我们还创建了 4 个名为“ jp1 ”、“ jp2 ”、“ jp3 ”、“ jp4 的组件，然后使用 add() 方法将其添加到 JFrame 中。我们将分别使用 setSize() 、 setVisible() 和 setTitle() 方法设置框架的大小、可见性和标题。布局使用 setLayout() 方法设置。
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to show Example of CardLayout.
// in java. Importing different Package.
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
// class extends JFrame
public class CardLayoutDemo extends JFrame {
// Initialization the value of
// current card is 1 .
private int currentCard = 1;
// Declaration of objects
// of CardLayout class.
private CardLayout cl;
public CardLayoutDemo()
{
// Function to set visibility of JFrame
setTitle("Card Layout Example");
// Function to set visibility of JFrame
setSize(300, 150);
// Creating Object of "Jpanel" class
JPanel cardPanel = new JPanel();
// Initialization of object "c1"
// of CardLayout class.
cl = new CardLayout();
// set the layout
cardPanel.setLayout(cl);
// Initialization of object
// "jp1" of JPanel class.
JPanel jp1 = new JPanel();
// Initialization of object
// "jp2" of CardLayout class.
JPanel jp2 = new JPanel();
// Initialization of object
// "jp3" of CardLayout class.
JPanel jp3 = new JPanel();
// Initialization of object
// "jp4" of CardLayout class.
JPanel jp4 = new JPanel();
// Initialization of object
// "jl1" of JLabel class.
JLabel jl1 = new JLabel("Card1");
// Initialization of object
// "jl2" of JLabel class.
JLabel jl2 = new JLabel("Card2");
// Initialization of object
// "jl3" of JLabel class.
JLabel jl3 = new JLabel("Card3");
// Initialization of object
// "jl4" of JLabel class.
JLabel jl4 = new JLabel("Card4");
// Adding JPanel "jp1" on JFrame.
jp1.add(jl1);
// Adding JPanel "jp2" on JFrame.
jp2.add(jl2);
// Adding JPanel "jp3" on JFrame.
jp3.add(jl3);
// Adding JPanel "jp4" on JFrame.
jp4.add(jl4);
// Adding the cardPanel on "jp1"
cardPanel.add(jp1, "1");
// Adding the cardPanel on "jp2"
cardPanel.add(jp2, "2");
// Adding the cardPanel on "jp3"
cardPanel.add(jp3, "3");
// Adding the cardPanel on "jp4"
cardPanel.add(jp4, "4");
// Creating Object of "JPanel" class
JPanel buttonPanel = new JPanel();
// Initialization of object
// "firstbtn" of JButton class.
JButton firstBtn = new JButton("First");
// Initialization of object
// "nextbtn" of JButton class.
JButton nextBtn = new JButton("Next");
// Initialization of object
// "previousbtn" of JButton class.
JButton previousBtn = new JButton("Previous");
// Initialization of object
// "lastbtn" of JButton class.
JButton lastBtn = new JButton("Last");
// Adding JButton "firstbtn" on JFrame.
buttonPanel.add(firstBtn);
// Adding JButton "nextbtn" on JFrame.
buttonPanel.add(nextBtn);
// Adding JButton "previousbtn" on JFrame.
buttonPanel.add(previousBtn);
// Adding JButton "lastbtn" on JFrame.
buttonPanel.add(lastBtn);
// add firstbtn in ActionListener
firstBtn.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
// used first c1 CardLayout
cl.first(cardPanel);
// value of currentcard is 1
currentCard = 1;
}
});
// add lastbtn in ActionListener
lastBtn.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
// used last c1 CardLayout
cl.last(cardPanel);
// value of currentcard is 4
currentCard = 4;
}
});
// add nextbtn in ActionListener
nextBtn.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
// if condition apply
if (currentCard < 4)
{
// increment the value of currentcard by 1
currentCard += 1;
// show the value of currentcard
cl.show(cardPanel, "" + (currentCard));
}
}
});
// add previousbtn in ActionListener
previousBtn.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
// if condition apply
if (currentCard > 1) {
// decrement the value
// of currentcard by 1
currentCard -= 1;
// show the value of currentcard
cl.show(cardPanel, "" + (currentCard));
}
}
});
// used to get content pane
getContentPane().add(cardPanel, BorderLayout.NORTH);
// used to get content pane
getContentPane().add(buttonPanel, BorderLayout.SOUTH);
}
// Main Method
public static void main(String[] args)
{
// Creating Object of CardLayoutDemo class.
CardLayoutDemo cl = new CardLayoutDemo();
// Function to set default operation of JFrame.
cl.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Function to set visibility of JFrame.
cl.setVisible(true);
}
}
输出:
[https://media.geeksforgeeks.org/wp-content/uploads/CardLayout-2.mp4](https://media.geeksforgeeks.org/wp-content/uploads/CardLayout-2.mp4)注意:上述程序可能无法在在线 IDE 中运行。请使用离线编译器。
参考:T2T4】
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