java - Java 中的进度条

Question

我有一个 Java (Swing) 表单从数据库加载大量数据。我想在程序实际加载时显示进度条。

我该怎么做？

代码如下:

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.sql.*;
import java.applet.*;
import java.util.*;
import java.awt.Color;

public class bookshow extends JFrame implements MouseListener, ActionListener {

    JPanel p1, p2, p3;
    JLabel l1, l2, l3, l4;
    ImageIcon image;
    JButton b[] = new JButton[84];
    JButton btnocc, btnbook, btnsel;
    ResultSet rs;
    private JMenuBar menuBar = new JMenuBar();
    private JMenuItem exit, home, save;
    private JMenu fileMenu, gotoMenu;
    public int cnt = 0, x = 150, y = 90, i, j, put = 0, k = 0, avail = 1, point, x1, y1, count = 0, quan;
    public static int prev_click = -1, xpos, ypos;
    public static int prev[] = new int[5];
    public static int pos[][] = new int[5][2];
    public String movname, movdate, movtime;

    public bookshow() {
        avail = 1;

        try {

            String sql = "Select * from Pass";
            String url = "jdbc:odbc:tbs";
            Connection con = DriverManager.getConnection(url);
            Statement s = con.createStatement();
            rs = s.executeQuery(sql);
            while (rs.next()) {
                movname = rs.getString("movname");
                movdate = rs.getString("movdate");
                movtime = rs.getString("movtime");
                quan = Integer.parseInt(rs.getString("Quantity"));
            }
        } catch (Exception ex) {
            System.out.println(ex);
        }

        try {

            String sql = "Delete from Pass";
            String url = "jdbc:odbc:tbs";
            Connection con = DriverManager.getConnection(url);
            Statement s = con.createStatement();
            s.executeUpdate(sql);
            con.close();
        } catch (Exception ex) {
            System.out.println(ex);
        }

        setTitle("Select Ticket");
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        p1 = new JPanel();
        getContentPane().add(p1);
        p1.setLayout(null);
        p1.setBackground(Color.white);

        setJMenuBar(menuBar);

        fileMenu = new JMenu("File");
        menuBar.add(fileMenu);

        exit = new JMenuItem("Exit");
        exit.addActionListener(this);
        fileMenu.add(exit);
        exit.setAccelerator(KeyStroke.getKeyStroke('E', Event.CTRL_MASK));

        save = new JMenuItem("Save");
        save.addActionListener(this);
        fileMenu.add(save);
        save.setAccelerator(KeyStroke.getKeyStroke('S', Event.CTRL_MASK));

        gotoMenu = new JMenu("Go To");
        menuBar.add(gotoMenu);

        home = new JMenuItem("Home");
        //exit.addActionListener(this);
        gotoMenu.add(home);
        home.setAccelerator(KeyStroke.getKeyStroke('H', Event.CTRL_MASK));

        p2 = new JPanel();
        p2.setLayout(null);
        p2.setBackground(Color.lightGray);
        p2.setBounds(100, 50, 500, 20);
        p1.add(p2);

        l1 = new JLabel("GOLD");
        l1.setBounds(240, 0, 100, 20);
        p2.add(l1);
        l1.setBackground(Color.red);

        try {

            String sql = "Select * from Book";
            String url = "jdbc:odbc:tbs";
            Connection con = DriverManager.getConnection(url);
            Statement s = con.createStatement();
            rs = s.executeQuery(sql);
            while (rs.next()) {

                String getname = rs.getString("MovName");
                String getdate = rs.getString("MovDate");
                String gettime = rs.getString("MovTime");

                if (movname.equalsIgnoreCase(getname) && movdate.equals(getdate) && movtime.equals(gettime)) {
                    put = 1;
                    break;
                }
            }
        } catch (Exception ex) {
            System.out.println(ex);
        }

        for (i = 1; i <= 4; i++) {

            for (j = 1; j <= 14; j++) {
                point = 0;
                b[cnt] = new JButton();
                b[cnt].setBounds(x, y, 20, 20);
                b[cnt].setBackground(Color.white);
                p1.add(b[cnt]);

                if (put == 0) {
                    try {

                        String sql = "Insert into Book values('" + movname + "','" + movtime + "','" + movdate + "'," + x + "," + y + ",1)";
                        String url = "jdbc:odbc:tbs";
                        Connection con = DriverManager.getConnection(url);
                        Statement s = con.createStatement();
                        s.executeUpdate(sql);
                        con.close();
                    } catch (Exception ex) {
                        System.out.println(ex);
                    }
                } else {

                    try {

                        String sql = "Select * from Book";
                        String url = "jdbc:odbc:tbs";
                        Connection con = DriverManager.getConnection(url);
                        Statement s = con.createStatement();
                        rs = s.executeQuery(sql);
                        while (rs.next()) {

                            String getname = rs.getString("MovName");
                            String getdate = rs.getString("MovDate");
                            String gettime = rs.getString("MovTime");
                            avail = Integer.parseInt(rs.getString("Avail"));

                            if (movname.equalsIgnoreCase(getname) && movdate.equals(getdate) && movtime.equals(gettime)) {
                                k++;
                                if (avail == 0 && k == (cnt + 1)) {
                                    b[cnt].setBackground(Color.red);
                                    point = 1;
                                    b[cnt].setEnabled(false);
                                }
                            }
                        }
                    } catch (Exception ex) {
                        System.out.println(ex);
                    }
                }

                if (point == 0) {
                    b[cnt].addMouseListener(this);
                }

                cnt++;
                x = x + 30;
                k = 0;

            }

            x = 150;

            y = y + 40;
        }

        y = 300;
        x = 150;

        p3 = new JPanel();
        p3.setLayout(null);
        p3.setBackground(Color.lightGray);
        p3.setBounds(100, 260, 500, 20);
        p1.add(p3);

        l2 = new JLabel("ECONOMY");
        l2.setBounds(220, 0, 100, 20);
        p3.add(l2);
        l2.setBackground(Color.red);

        for (i = 1; i <= 2; i++) {

            for (j = 1; j <= 14; j++) {
                point = 0;

                b[cnt] = new JButton();
                b[cnt].setBounds(x, y, 20, 20);
                b[cnt].setBackground(Color.white);
                p1.add(b[cnt]);

                if (put == 0) {
                    try {
                        String sql = "Insert into Book values('" + movname + "','" + movtime + "','" + movdate + "'," + x + "," + y + ",1)";
                        String url = "jdbc:odbc:tbs";
                        Connection con = DriverManager.getConnection(url);
                        Statement s = con.createStatement();
                        s.executeUpdate(sql);
                        con.close();
                    } catch (Exception ex) {
                        System.out.println(ex);
                    }
                } else {

                    try {

                        String sql = "Select * from Book";
                        String url = "jdbc:odbc:tbs";
                        Connection con = DriverManager.getConnection(url);
                        Statement s = con.createStatement();
                        rs = s.executeQuery(sql);
                        while (rs.next()) {

                            String getname = rs.getString("MovName");
                            String getdate = rs.getString("MovDate");
                            String gettime = rs.getString("MovTime");
                            avail = Integer.parseInt(rs.getString("Avail"));

                            if (movname.equalsIgnoreCase(getname) && movdate.equals(getdate) && movtime.equals(gettime)) {
                                k++;
                                if (avail == 0 && k == (cnt + 1)) {
                                    b[cnt].setBackground(Color.red);
                                    point = 1;
                                    b[cnt].setEnabled(false);
                                }
                            }
                        }
                    } catch (Exception ex) {
                        System.out.println(ex);
                    }
                }

                if (point == 0) {
                    b[cnt].addMouseListener(this);
                }

                cnt++;
                x = x + 30;
                k = 0;
            }
            x = 150;

            y = y + 40;
        }

        image = new ImageIcon("screen.jpg");

        l3 = new JLabel(image);
        l3.setBounds(70, y + 20, 600, 54);
        p1.add(l3);

        l4 = new JLabel("Seat to Occupy");
        l4.setBounds(140, 490, 100, 15);
        p1.add(l4);

        btnocc = new JButton();
        btnocc.setBounds(260, 490, 15, 15);
        btnocc.setBackground(Color.white);
        p1.add(btnocc);

        l4 = new JLabel("Booked seat");
        l4.setBounds(320, 490, 80, 15);
        p1.add(l4);

        btnbook = new JButton();
        btnbook.setBounds(410, 490, 15, 15);
        btnbook.setBackground(Color.red);
        p1.add(btnbook);

        l4 = new JLabel("Current selection");
        l4.setBounds(460, 490, 100, 15);
        p1.add(l4);

        btnsel = new JButton();
        btnsel.setBounds(570, 490, 15, 15);
        btnsel.setBackground(Color.green);
        p1.add(btnsel);

        setSize(770, 650);
        setVisible(true);
    }

    public void mousePressed(MouseEvent e) {
    }

    public void mouseReleased(MouseEvent e) {
    }

    public void mouseEntered(MouseEvent e) {
        Cursor mycursor = new Cursor(Cursor.HAND_CURSOR);
        setCursor(mycursor);

    }

    public void mouseExited(MouseEvent e) {
        Cursor mycursor = new Cursor(Cursor.DEFAULT_CURSOR);
        setCursor(mycursor);
    }

    public void mouseClicked(MouseEvent e) {
        int row, col, ex;

        for (i = 0; i < cnt; i++) {
            if (e.getSource().equals(b[i])) {

                if (count < quan) {
                    prev[count] = i;
                    b[prev[count]].setBackground(Color.green);

                    row = i / 14;
                    col = i % 14;

                    x1 = 150 + (30 * col);

                    if (row >= 0 && row <= 3) {
                        y1 = 90 + (40 * row);
                    } else {
                        y1 = 300 + (40 * (row - 4));
                    }

                    pos[count][0] = x1;
                    pos[count][1] = y1;

                    count++;
                } else {
                    ex = prev[0];
                    b[ex].setBackground(Color.white);

                    for (int j = 0; j <= (count - 1); j++) {
                        prev[j] = prev[j + 1];
                        pos[j][0] = pos[j + 1][0];
                        pos[j][1] = pos[j + 1][1];
                    }

                    prev[count - 1] = i;

                    row = i / 14;
                    col = i % 14;

                    x1 = 150 + (30 * col);

                    if (row >= 0 && row <= 3) {
                        y1 = 90 + (40 * row);
                    } else {
                        y1 = 300 + (40 * (row - 4));
                    }

                    pos[count - 1][0] = x1;
                    pos[count - 1][1] = y1;

                    for (int j = 0; j <= (count - 1); j++) {
                        b[prev[j]].setBackground(Color.green);
                    }
                    count = quan;
                }

            }
        }
    }

    public void actionPerformed(ActionEvent e) {

        if (e.getSource() == save) {
            if (count != quan) {
                JOptionPane.showMessageDialog(null, "Please select the exact numbers of seat", "Error", JOptionPane.ERROR_MESSAGE);
            } else {

                for (i = 0; i < count; i++) {

                    try {

                        String sql = "Update Book set Avail=0 where MovName='" + movname + "' AND MovDate='" + movdate + "' AND MovTime='" + movtime + "' AND X=" + pos[i][0] + " AND y=" + pos[i][1] + " ";
                        String url = "jdbc:odbc:tbs";
                        Connection con = DriverManager.getConnection(url);
                        Statement s = con.createStatement();
                        s.executeUpdate(sql);
                        con.close();
                    } catch (Exception ex) {
                        System.out.println(ex);
                    }

                    setVisible(false);
                    bookmain bm = new bookmain();
                }
            }
        }
    }

    public static void main(String args[]) {
        bookshow mm = new bookshow();
    }
}

Answer 1

Java progress bar tutorial应该有帮助。

另一个示例可以在 SwingWorker 中找到java 文档条目。

不是调用 nextPrimeNumber()，在您的情况下可能是 processNextBook()。

要计算出进度，您可以使用类似的想法，例如将变量更改为代码中有意义的内容，例如。 setProgress(100 * booksProcessed.size()/books.size());

下面的代码应该可以让您了解如何实现您的目标。

class PrimeNumbersTask extends 
         SwingWorker<List<Integer>, Integer> {
     PrimeNumbersTask(JTextArea textArea, int numbersToFind) { 
         //initialize 
     }

     @Override
     public List<Integer> doInBackground() {
         while (! enough && ! isCancelled()) {
                 number = nextPrimeNumber();
                 publish(number);
                 setProgress(100 * numbers.size() / numbersToFind);
             }
         }
         return numbers;
     }

     @Override
     protected void process(List<Integer> chunks) {
         for (int number : chunks) {
             textArea.append(number + "\n");
         }
     }
 }

 JTextArea textArea = new JTextArea();
 final JProgressBar progressBar = new JProgressBar(0, 100);
 PrimeNumbersTask task = new PrimeNumbersTask(textArea, N);
 task.addPropertyChangeListener(
     new PropertyChangeListener() {
         public  void propertyChange(PropertyChangeEvent evt) {
             if ("progress".equals(evt.getPropertyName())) {
                 progressBar.setValue((Integer)evt.getNewValue());
             }
         }
     });