排序例子：利用选择排序法（Selection sort）对数组排序

实现：自动生成随机数，并排序；

基本思想：从待排序元素中先出最小（或最大）的一个元素，顺序放在已排好序的最后，直到全部待排序的数据元素排完。

设计：主界面设计-button部分-textField-计算部分

效果图：

重要计算部分代码：

int index;
        for (int i = 1; i < array.length; i++) {
            index = 0;
            for (int j = 1; j <= array.length - i; j++) {
                if (array[j] > array[index]) {
                    index = j;// 查找最大值
                }
            }
            // 交换在位置array.length-i和index(最大值)两个数
            int temp = array[array.length - i];
            array[array.length - i] = array[index];
            array[index] = temp;

完整代码：

package com.lixiyu;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.border.EmptyBorder;
public class SelectSort extends JFrame {
                                                                           
    /**
     *
     */
    private static final long serialVersionUID = 6824538613659403529L;//序列化保持对象兼容性
    private JPanel contentPane;//容器
                                                                           
    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {//调用
            public void run() {
                try {
                    SelectSort frame = new SelectSort();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
                                                                           
    /**
     * Create the frame.
     */
    public SelectSort() {
        setTitle("使用选择排序法对数组排序");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        GridBagLayout gbl_contentPane = new GridBagLayout();
        gbl_contentPane.columnWidths = new int[] { 0, 0 };
        gbl_contentPane.rowHeights = new int[] { 0, 0, 0, 0, 0 };
        gbl_contentPane.columnWeights = new double[] { 1.0, Double.MIN_VALUE };
        gbl_contentPane.rowWeights = new double[] { 1.0, 0.0, 1.0, 0.0,
                Double.MIN_VALUE };
        contentPane.setLayout(gbl_contentPane);
                                                                               
        JScrollPane scrollPane = new JScrollPane();
        GridBagConstraints gbc_scrollPane = new GridBagConstraints();
        gbc_scrollPane.insets = new Insets(0, 0, 5, 0);
        gbc_scrollPane.fill = GridBagConstraints.BOTH;
        gbc_scrollPane.gridx = 0;
        gbc_scrollPane.gridy = 0;
        contentPane.add(scrollPane, gbc_scrollPane);
                                                                               
        textArea1 = new JTextArea();
        scrollPane.setViewportView(textArea1);
                                                                               
        JButton button = new JButton("生成随机数");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                do_button_actionPerformed(e);
            }
        });
        GridBagConstraints gbc_button = new GridBagConstraints();
        gbc_button.insets = new Insets(0, 0, 5, 0);
        gbc_button.gridx = 0;
        gbc_button.gridy = 1;
        contentPane.add(button, gbc_button);
                                                                               
        JScrollPane scrollPane_1 = new JScrollPane();
        GridBagConstraints gbc_scrollPane_1 = new GridBagConstraints();
        gbc_scrollPane_1.insets = new Insets(0, 0, 5, 0);
        gbc_scrollPane_1.fill = GridBagConstraints.BOTH;
        gbc_scrollPane_1.gridx = 0;
        gbc_scrollPane_1.gridy = 2;
        contentPane.add(scrollPane_1, gbc_scrollPane_1);
                                                                               
        textArea2 = new JTextArea();
        scrollPane_1.setViewportView(textArea2);
                                                                               
        JButton button_1 = new JButton("排序");
        button_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                do_button_1_actionPerformed(e);
            }
        });
        GridBagConstraints gbc_button_1 = new GridBagConstraints();
        gbc_button_1.gridx = 0;
        gbc_button_1.gridy = 3;
        contentPane.add(button_1, gbc_button_1);
    }
                                                                           
    private int[] array = new int[10];
    private JTextArea textArea1;
    private JTextArea textArea2;
                                                                           
    protected void do_button_actionPerformed(ActionEvent e) {
        Random random = new Random();// 创建随机数对象
        textArea1.setText("");// 清空文本域
        for (int i = 0; i < array.length; i++) {// 初始化数组元素
            array[i] = random.nextInt(50);// 生成50以内的随机数
            textArea1.append(array[i]+"  ");// 把数组元素显示的文本域控件中
        }
    }
                                                                           
    protected void do_button_1_actionPerformed(ActionEvent e) {
        textArea2.setText("");// 清空文本域
        int index;
        for (int i = 1; i < array.length; i++) {
            index = 0;
            for (int j = 1; j <= array.length - i; j++) {
                if (array[j] > array[index]) {
                    index = j;// 查找最大值
                }
            }
            // 交换在位置array.length-i和index(最大值)两个数
            int temp = array[array.length - i];
            array[array.length - i] = array[index];
            array[index] = temp;
        }
        for (int i = 0; i < array.length; i++) {
            textArea2.append(array[i] + "  ");// 把排序后的数组元素显示到文本域中
        }
    }
}

里面涉及到一个网格布局管理器GridBagLayout，其用法可参照API文档。等对这个用法更了解以后，应该会单独开个文章来写它的用法的。

词的官方解释：

The GridBagLayout class is a flexible layout manager that aligns components vertically, horizontally or along their baseline without requiring that the components be of the same size. Each GridBagLayout object maintains a dynamic, rectangular grid of cells, with each component occupying one or more cells, called its display area.

转载于:https://blog.51cto.com/lixiyu/1304109