JProgressBar在数据加载时摆动

Question

我有来自UI的服务器调用.它的响应时间有点高.所以我想在从服务器加载数据时显示进度条.我已尝试使用此方法的以下代码来显示进度条.一些我做错的地方当我calculateResult()按下按钮点击方法时,我没有看到进度条.我无需在进度条上显示任何百分比.它只需要显示数据正在加载.

//我试过以下代码

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.InvocationTargetException;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;

 public class MyProgressBarTest extends JFrame {
private static final long serialVersionUID = 1L;

private static JProgressBar progressBar;

public static void main(String[] args) {
    MyProgressBarTest obj = new MyProgressBarTest();
    obj.createGUI();
}

public void createGUI() {
    JPanel panel = new JPanel();
    JButton button = new JButton("Progress");

    progressBar = new JProgressBar();

    button.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent arg0) {

            MyCustomProgressBarDialog progressBarObj = new    MyCustomProgressBarDialog(progressBar);
            progressBarObj.createProgressUI();

            MyActionPerformer actionObj = new MyActionPerformer(progressBar);
            actionObj.execute();

            progressBarObj.setVisible(false);
        }
    });

//      panel.add(progressBar);
    panel.add(button);
    add(panel);

    setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
    setLocationRelativeTo(null);
//      pack();
    setSize(200, 300);
    setVisible(true);
}
}

class MyActionPerformer extends SwingWorker<String, Object> {

JProgressBar fProgressBar;

public MyActionPerformer(JProgressBar progressBar) {
    this.fProgressBar = progressBar;
    this.fProgressBar.setVisible(true);
    this.fProgressBar.setIndeterminate(true);
}

protected String doInBackground() throws Exception {

    calculateResult();
    return "Finished";
}

protected void done() {
    fProgressBar.setVisible(false);
}

public void calculateResult() {
    for (int i = 0; i < 500000; i++) {
        System.out.println("Progress Bar: " + i);
    }
}
}

class MyCustomProgressBarDialog extends JDialog {
private static JProgressBar progressBar;

public MyCustomProgressBarDialog(JProgressBar progressBar) {
    this.progressBar = progressBar;
}

public void createProgressUI() {
    add(progressBar);
    setLocationRelativeTo(null);
    setSize(50, 20);
    setVisible(true);
}
}

Answer 1

你的进度条立即消失的原因是你的 ActionListener

button.addActionListener(new ActionListener() {
  @Override
  public void actionPerformed(ActionEvent arg0) {
   MyCustomProgressBarDialog progressBarObj = new    MyCustomProgressBarDialog(progressBar);
   progressBarObj.createProgressUI();

   MyActionPerformer actionObj = new MyActionPerformer(progressBar);
   actionObj.execute();

   progressBarObj.setVisible(false);
  }
});

该actionObj.execute();方法不会阻塞(好东西或它没用),这意味着在您启动该SwingWorker调用之后,您将立即执行该progressBarObj.setVisible(false);语句.

这会导致进度条对话框消失.

我能想到2个解决方案

• 将对话框传递给SwingWorker同样setVisible( false )的done方法,并在方法中调用对话框SwingWorker
• 一个SwingWorker火灾PropertyChangeEventS的允许您确定多远进展.您可以使用此类侦听器在计算完成时隐藏对话框