如何在 java 中测量 JProgressBar 的任务进度

Question

我开发了一个 UI，我在其中获取压缩文件的共享文件夹位置，将其中包含的文件复制到我的系统。对其执行一些操作并再次将其存储到机器位置，所有这些事情都是使用 UI 完成的。为此，我现在想使用 JProgressBar，但我不了解如何借助线程来衡量进度。我看到了 JProgressBar 的教程，但没有帮助。

我写的代码：

 import java.awt.Toolkit;
 import java.awt.event.*;
 import javax.swing.*;
 import java.beans.*;
 import java.util.Random;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 public class ProgressBar extends javax.swing.JFrame {
/**
 * Creates new form ProgressBar
 */


public ProgressBar() {

    initComponents();

}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    jButton1 = new javax.swing.JButton();
    jProgressBar1 = new javax.swing.JProgressBar();
    jTextField1 = new javax.swing.JTextField();
    jScrollPane1 = new javax.swing.JScrollPane();
    jTextArea1 = new javax.swing.JTextArea();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jButton1.setText("ok");
    jButton1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton1ActionPerformed(evt);
        }
    });

    jProgressBar1.setStringPainted(true);

    jTextArea1.setColumns(20);
    jTextArea1.setRows(5);
    jScrollPane1.setViewportView(jTextArea1);

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGap(68, 68, 68)
                    .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 119, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addGap(44, 44, 44)
                    .addComponent(jButton1))
                .addGroup(layout.createSequentialGroup()
                    .addGap(150, 150, 150)
                    .addComponent(jProgressBar1, javax.swing.GroupLayout.PREFERRED_SIZE, 167, javax.swing.GroupLayout.PREFERRED_SIZE)))
            .addContainerGap(298, Short.MAX_VALUE))
        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
            .addGap(0, 0, Short.MAX_VALUE)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(99, 99, 99))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(41, 41, 41)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jButton1)
                .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(46, 46, 46)
            .addComponent(jProgressBar1, javax.swing.GroupLayout.PREFERRED_SIZE, 27, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(48, 48, 48)
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(91, Short.MAX_VALUE))
    );

    pack();
}// </editor-fold>                        

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:

    iterate();

}                                        

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(ProgressBar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(ProgressBar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(ProgressBar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(ProgressBar.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new ProgressBar().setVisible(true);

    });
}

public void iterate()
    {
        int i = 0;
        while(i<=100){    
        jProgressBar1.setValue(i);    
        i=i+15;  

        try{Thread.sleep(700);}catch(Exception e){}    
    }    
  }

// Variables declaration - do not modify                     
private javax.swing.JButton jButton1;
private javax.swing.JProgressBar jProgressBar1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea jTextArea1;
private javax.swing.JTextField jTextField1;
// End of variables declaration                   
}

Answer 1

关键是你首先定义一个可以衡量的值来报告你的进度。

示例：您对上面列出的每个步骤给予 15、20 points/percent，每完成一个这样的步骤，您的进度就会增加。（您可以尝试预先测量执行时间，为不同的步骤赋予不同的“权重”；或者您只是让每个步骤贡献相同的“数量”以最终达到“100%”）。

对于操作方法，教程中肯定有描述！

这里的一个关键方面是线程。在您的示例中，您的 main 线程在进度条上调用 setValue()。这是行不通的。当您返回 oracle tutorial 时，您会发现：

Task is a subclass of javax.swing.SwingWorker. The Task instance does three important things for ProgressBarDemo:

The instance invokes the doInBackground in a separate thread. This is where the long-running task is actually executed. Using a background thread instead of the event-dispatching thread prevents the user interface from freezing while the task is running.

When the background task is complete, the instance invokes the done method in the event-dispatching thread.

The instance maintains a bound property, progress, that is updated to indicate the progress of the task. The propertyChange method is invoked each time progress changes.

Answer 2

简单。看看 ProgressMonitorInputStream.

如何在 java 中测量 JProgressBar 的任务进度

How to measure progress of task for JProgressBar in java

java

swing

jprogressbar