进度条Java

我正在使用JProgressBar来显示进度。 但是，如何将progressBar显示为从0加载到100？ 我从互联网及其工作中获得了代码，除了progressBar没有加载。

码

progressFrame = new JFrame(); // frame to display progress bar progressBar = new JProgressBar(0,100); progressBar.setValue(0); progressBar.setStringPainted(true); progressFrame.add(progressBar); new SwingWorker() { protected Void doInBackground() throws SQLException, ClassNotFoundException { Class.forName("oracle.jdbc.driver.OracleDriver"); progressBar.setValue(0); frame.setEnabled(false); // frame = main frame //tableclass creates a JTable with data from database tableclass = new TheDatabaseTable(deptName);//it takes time to create progressBar.setValue(50); frame.getContentPane().removeAll(); frame.setContentPane(tableclass); frame.validate(); frame.repaint(); progressBar.setValue(100); //progressFrame.dispose(); return null; }; protected void done() { //progressFrame.setVisible(false); frame.setVisible(true); progressFrame.dispose(); frame.setEnabled(true); } }.execute(); 

如果有人编辑上述代码，我将不胜感激。 谢谢。

Answer 1

你必须使用线程。 设计一个实现Runnable接口的类，它将更新这样的值。

 class ProgressBarUpdator implements java.lang.Runnable { /** * Progress bar that shows the current status */ private javax.swing.JProgressBar jpb = null; /** * Progress bar value */ private java.lang.Integer value = null; /** * Constructor * @param jpb The progress bar this has to update */ public ProgressBarUpdator(javax.swing.JProgressBar jpb) { this.jpb = jpb; jpb.setMaximum(100); } /** * Sets the value to the progress bar * @param value Value to set */ public void setValue(java.lang.Integer value) { this.value = value; } /** * Action of the thread will be executed here. The value of the progress bar will be set here. */ public void run() { do { if (value != null) { jpb.setValue((int)java.lang.Math.round(java.lang.Math.floor(value.intValue() * 100 / maximum))); } try { java.lang.Thread.sleep(100L); } catch (java.lang.InterruptedException ex) { ex.printStackTrace(); } } while (value == null || value.intValue() < jpb.getMaximum()); } } 

并且在你的frame类中使用progressBar和这样的新类

 ProgressBarUpdator ju = new ProgressBarUpdator(progressBar); new java.lang.Thread(ju).start(); 

每当您想要更改值时，只需使用该语句即可

 ju.setValue([Value to set]); 

Answer 2

得从网上爱代码……哦……

您所拥有的代码违反了Swing的单线规则，因此是一个不好的例子。

SwingWorker有很多选项。 您可以publish进度并使用process方法更新进度条，也可以使用PropertyChangeListener并监视通过调用SwingWorker的setProgress方法创建的进度更改事件

 import java.awt.BorderLayout; 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.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JProgressBar; import javax.swing.SwingWorker; import javax.swing.UIManager; import javax.swing.UnsupportedLookAndFeelException; import javax.swing.border.EmptyBorder; public class SwingWorkerProgress { public static void main(String[] args) { new SwingWorkerProgress(); } public SwingWorkerProgress() { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { } JFrame frame = new JFrame("Testing"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLayout(new BorderLayout()); frame.add(new TestPane()); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } }); } public class TestPane extends JPanel { private JProgressBar pbProgress; private JButton start; public TestPane() { setBorder(new EmptyBorder(10, 10, 10, 10)); pbProgress = new JProgressBar(); setLayout(new GridBagLayout()); GridBagConstraints gbc = new GridBagConstraints(); gbc.insets = new Insets(4, 4, 4, 4); gbc.gridx = 0; gbc.gridy = 0; add(pbProgress, gbc); start = new JButton("Start"); gbc.gridy++; add(start, gbc); start.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { start.setEnabled(false); ProgressWorker pw = new ProgressWorker(); pw.addPropertyChangeListener(new PropertyChangeListener() { @Override public void propertyChange(PropertyChangeEvent evt) { String name = evt.getPropertyName(); if (name.equals("progress")) { int progress = (int) evt.getNewValue(); pbProgress.setValue(progress); repaint(); } else if (name.equals("state")) { SwingWorker.StateValue state = (SwingWorker.StateValue) evt.getNewValue(); switch (state) { case DONE: start.setEnabled(true); break; } } } }); pw.execute(); } }); } } public class ProgressWorker extends SwingWorker { @Override protected Object doInBackground() throws Exception { int i = 0; int max = 2000; while (i < max) { i += 10; int progress = Math.round(((float)i / (float)max) * 100f); setProgress(progress); try { Thread.sleep(25); } catch (Exception e) { e.printStackTrace(); } } return null; } } } 

Answer 3

 import java.awt.GridBagLayout; import javax.swing.JFrame; import javax.swing.JProgressBar; public class ProgressBar { /** * JProgressBar * * @throws InterruptedException */ public static void main(String[] args) throws InterruptedException { JFrame frame = new JFrame("New Window"); frame.setSize(600, 400); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLocationRelativeTo(null); frame.setLayout(new GridBagLayout()); frame.setVisible(true); //JLabel textLoad = new JLabel(); //textLoad.setText("Loading ...."); JProgressBar progressBar = new JProgressBar(); progressBar.setMinimum(0); progressBar.setMaximum(100); progressBar.setStringPainted(true); progressBar.setIndeterminate(true); frame.add(progressBar); for (int i = progressBar.getMinimum(); i <= progressBar.getMaximum(); i++) { Thread.sleep(500); progressBar.setValue(i); } textLoad.setText("Done !"); } } 

Answer 4

 /* By Dr. Amit Kumar Kapoor Assistant Professor, Maharaja Agrasen Institute of Management & Technology, Jagadhri E-mail ID: [e-mail] */ import java.awt.*; import javax.swing.*; import java.awt.event.*; class progressbardemo extends JFrame implements ActionListener { JProgressBar pb; JButton b1; progressbardemo() { super("Progressbar"); setLayout(null); b1=new JButton("Click"); b1.setBackground(Color.yellow); pb=new JProgressBar(1,100); pb.setValue(0); pb.setStringPainted(true); pb.setForeground(Color.red); pb.setBackground(Color.white); b1.setBounds(20,20,80,25);pb.setBounds(110,20,200,25); pb.setVisible(false); add(b1); add(pb); b1.addActionListener(this); setResizable(false); setDefaultCloseOperation(EXIT_ON_CLOSE); } public void actionPerformed(ActionEvent e) { int i=0; if(e.getSource()==b1) { pb.setVisible(true); try { while(i<=100) { Thread.sleep(50); pb.paintImmediately(0, 0, 200, 25); pb.setValue(i); i++; } } catch(Exception e1) { System.out.print("Caughted exception is ="+e1); } } } public static void main(String arg[]) { progressbardemo m=new progressbardemo(); m.setSize(330,100); m.setVisible(true); Dimension dimension = Toolkit.getDefaultToolkit().getScreenSize(); int x = (int) ((dimension.getWidth() - m.getWidth()) / 2); int y = (int) ((dimension.getHeight() - m.getHeight()) / 2); m.setLocation(x, y); } }