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;
    private JPanel contentPane;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    SelectSort frame = new SelectSort();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public SelectSort() {
        setTitle("使用選擇排序法對數組排序");
        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("生成隨機數");
        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();// 創建隨機數對象
        textArea1.setText("");// 清空文本域
        for (int i = 0; i < array.length; i++) {// 初始化數組元素
            array[i] = random.nextInt(50);// 生成50以內的隨機數
            textArea1.append(array[i]+"  ");// 把數組元素顯示的文本域控件中
        }
    }

    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
                }
            }
            // 交換在位置array.length-i和index(最大值)兩個數
            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] + "  ");// 把排序后的數組元素顯示到文本域中
        }
    }
}