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Java语言常用布局管理器及其案例
2023-06-17 10:05:05 深夜i     10     0
Java语言 布局管理器 案例

Java语言中常用的布局管理器有FlowLayout、BorderLayout、GridLayout、CardLayout、GridBagLayout等。下面分别介绍这几种布局管理器的使用方法和案例。

1. FlowLayout

FlowLayout是最简单的一种布局管理器，它会按照组件的加入顺序自左向右排列，直到一行排满为止，然后自动换行。示例代码如下：

import javax.swing.*;
import java.awt.*;
public class FlowLayoutDemo {
  public static void main(String[] args) {
    JFrame frame = new JFrame("FlowLayoutDemo");
    JPanel panel = new JPanel(new FlowLayout());
    panel.add(new JButton("Button1"));
    panel.add(new JButton("Button2"));
    panel.add(new JButton("Button3"));
    panel.add(new JButton("Button4"));
    panel.add(new JButton("Button5"));
    frame.add(panel);
    frame.setSize(300, 200);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}

2. BorderLayout

BorderLayout将容器分为五个区域：北、南、东、西、中。添加组件时需要指定组件位于哪一个方位。示例代码如下：

import javax.swing.*;
import java.awt.*;
public class BorderLayoutDemo {
  public static void main(String[] args) {
    JFrame frame = new JFrame("BorderLayoutDemo");
    JPanel panel = new JPanel(new BorderLayout());
    panel.add(new JButton("North"), BorderLayout.NORTH);
    panel.add(new JButton("South"), BorderLayout.SOUTH);
    panel.add(new JButton("East"), BorderLayout.EAST);
    panel.add(new JButton("West"), BorderLayout.WEST);
    panel.add(new JButton("Center"), BorderLayout.CENTER);
    frame.add(panel);
    frame.setSize(300, 200);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}

3. GridLayout

GridLayout将容器按照行列格子划分，每个格子放置一个组件。示例代码如下：

import javax.swing.*;
import java.awt.*;
public class GridLayoutDemo {
  public static void main(String[] args) {
    JFrame frame = new JFrame("GridLayoutDemo");
    JPanel panel = new JPanel(new GridLayout(2, 3));
    panel.add(new JButton("Button1"));
    panel.add(new JButton("Button2"));
    panel.add(new JButton("Button3"));
    panel.add(new JButton("Button4"));
    panel.add(new JButton("Button5"));
    panel.add(new JButton("Button6"));
    frame.add(panel);
    frame.setSize(300, 200);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}

4. CardLayout

CardLayout将容器中的组件按照卡片的形式堆叠起来，只显示最上层的组件，其余组件被遮挡。示例代码如下：

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class CardLayoutDemo {
  public static void main(String[] args) {
    JFrame frame = new JFrame("CardLayoutDemo");
    JPanel panel = new JPanel(new CardLayout());
    JButton button1 = new JButton("Button1");
    JButton button2 = new JButton("Button2");
    JButton button3 = new JButton("Button3");
    button1.addActionListener(new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent e) {
        CardLayout layout = (CardLayout) panel.getLayout();
        layout.show(panel, "Button2");
      }
    });
    button2.addActionListener(new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent e) {
        CardLayout layout = (CardLayout) panel.getLayout();
        layout.show(panel, "Button3");
      }
    });
    button3.addActionListener(new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent e) {
        CardLayout layout = (CardLayout) panel.getLayout();
        layout.show(panel, "Button1");
      }
    });
    panel.add(button1, "Button1");
    panel.add(button2, "Button2");
    panel.add(button3, "Button3");
    frame.add(panel);
    frame.setSize(300, 200);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}

5. GridBagLayout

GridBagLayout是最复杂的一种布局管理器，通过使用行和列上的网格来定位组件。示例代码如下：

import javax.swing.*;
import java.awt.*;
public class GridBagLayoutDemo {
  public static void main(String[] args) {
    JFrame frame = new JFrame("GridBagLayoutDemo");
    JPanel panel = new JPanel(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.weightx = 1.0;
    gbc.weighty = 1.0;
    JButton button1 = new JButton("Button1");
    gbc.gridx = 0;
    gbc.gridy = 0;
    gbc.gridwidth = 2;
    gbc.fill = GridBagConstraints.BOTH;
    panel.add(button1, gbc);
    JButton button2 = new JButton("Button2");
    gbc.gridx = 2;
    gbc.gridy = 0;
    gbc.gridwidth = 1;
    gbc.fill = GridBagConstraints.BOTH;
    panel.add(button2, gbc);
    JButton button3 = new JButton("Button3");
    gbc.gridx = 0;
    gbc.gridy = 1;
    gbc.gridwidth = 1;
    gbc.fill = GridBagConstraints.BOTH;
    panel.add(button3, gbc);
    JButton button4 = new JButton("Button4");
    gbc.gridx = 1;
    gbc.gridy = 1;
    gbc.gridwidth = 1;
    gbc.fill = GridBagConstraints.BOTH;
    panel.add(button4, gbc);
    JButton button5 = new JButton("Button5");
    gbc.gridx = 2;
    gbc.gridy = 1;
    gbc.gridwidth = 1;
    gbc.fill = GridBagConstraints.BOTH;
    panel.add(button5, gbc);
    frame.add(panel);
    frame.setSize(300, 200);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}
  
  

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