java程序示例_Java：进度条示例程序

快来打我* 2022-12-07 12:08 215阅读 0赞

java程序示例

## 背景 **(** Background **)** ##

The [Java code][] listing shows an example of how to use the `JProgressBar` and SwingWorker classes. When run the Java application will show a [GUI][] which contains a `JButton`, a `JProgressBar` and two `JCheckBoxes`. The `JButton` starts a simulated task whose progress is tracked by the `JProgressBar`. The `JCheckBoxes` control whether the progress is determined or indeterminate.

[Java代码][Java code]清单显示了如何使用`JProgressBar`和SwingWorker类的示例。 运行时，Java应用程序将显示一个[GUI][] ，其中包含一个`JButton` ，一个`JProgressBar`和两个`JCheckBoxes` 。 `JButton`启动一个模拟任务，其进度由`JProgressBar`跟踪。 `JCheckBoxes`控制进度是确定的还是不确定的。

## Java代码 **(** Java Code **)** ##

![Businessman working at computer in office][]

Hero Images/Getty Images 英雄图片/盖蒂图片社

import java.awt.EventQueue;
    import javax.swing.JFrame;
    import javax.swing.JButton;
    import javax.swing.JProgressBar;
    import javax.swing.JCheckBox;
    import javax.swing.JPanel;
    import java.awt.event.ActionListener;
    import java.awt.event.ActionEvent;
    import javax.swing.SwingWorker;
    import java.awt.BorderLayout;
    import java.util.List;
    public class ProgressBarExamples {
    JProgressBar progressBar;
    JCheckBox progressType;
    JCheckBox switchType;
    final JButton goButton;
    //Note: Typically the main method will be in a
    //separate class. As this is a simple one class
    //example it's all in the one class.
    public static void main(String[] args) {
    //Use the event dispatch thread for Swing components
    EventQueue.invokeLater(new Runnable()
    {
    @Override
    public void run()
    {
    new ProgressBarExamples();
    }
    });
    }
    public ProgressBarExamples()
    {
    JFrame guiFrame = new JFrame();
    //make sure the program exits when the frame closes
    guiFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    guiFrame.setTitle("Creating a Table Example");
    guiFrame.setSize(700,200);
    //This will center the JFrame in the middle of the screen
    guiFrame.setLocationRelativeTo(null);
    goButton = new JButton("Go");
    goButton.setActionCommand("Go");
    goButton.addActionListener(new ActionListener()
    {
    //When the button is clicked the SwingWorker class is executed and
    //the button is disabled
    @Override
    public void actionPerformed(ActionEvent event)
    {
    progressBar.setStringPainted(progressType.isSelected());
    Sleeper task = new Sleeper();
    task.execute();
    goButton.setEnabled(false);
    }
    });
    //create a panel to hold the checkboxes
    JPanel chkPanel = new JPanel();
    //Create a checkbox to pick between a determined or indeterminate
    //progressbar
    progressType = new JCheckBox("Determined Progress Bar", true);
    progressType.addActionListener(new ActionListener()
    {
    @Override
    public void actionPerformed(ActionEvent event)
    {
    switchType.setEnabled(!progressType.isSelected());
    }
    });
    //Create a checkbox to switch progress bar modes
    switchType = new JCheckBox("Switch to Determined");
    switchType.setEnabled(false);
    chkPanel.add(progressType);
    chkPanel.add(switchType);
    //create progress bar
    progressBar = new JProgressBar(0, 100);
    progressBar.setValue(0);
    guiFrame.add(goButton, BorderLayout.WEST);
    guiFrame.add(progressBar, BorderLayout.CENTER);
    guiFrame.add(chkPanel, BorderLayout.SOUTH);
    guiFrame.setVisible(true);
    }
    //SwingWorker class is used to simulate a task being performed
    class Sleeper extends SwingWorker {
    @Override
    public Void doInBackground() throws InterruptedException {
    try
    {
    int progress = 0;
    while (progress chunks) {
    for (Integer chunk : chunks) {
    progressBar.setValue(chunk);
    //if the switchtype checkbox is selected then
    //change the progressbar to a determined type
    //once the progress has reached 50
    if (chunk > 49)
    {
    if (switchType.isEnabled() && switchType.isSelected())
    {
    progressBar.setStringPainted(true);
    }
    }
    }
    }
    //when the 'task' has finished re-enable the go button
    @Override
    public void done() {
    goButton.setEnabled(true);
    }
    }
    }

> 翻译自: [https://www.thoughtco.com/a-progress-bar-example-program-2033969][https_www.thoughtco.com_a-progress-bar-example-program-2033969]

java程序示例

[Java code]: https://www.thoughtco.com/javascript-programming-4133476
[GUI]: https://www.thoughtco.com/gui-2034108
[Businessman working at computer in office]: /images/20221123/33331db497cb460f9f6cea84d05644b1.png
[https_www.thoughtco.com_a-progress-bar-example-program-2033969]: https://www.thoughtco.com/a-progress-bar-example-program-2033969