如何将JProgressBar添加到JDialog中

Question

我试图将JProgressBar添加到JDialog，但JProgressBar从未出现过。以下是我的代码。有什么帮助吗？

        JDialog downloadingDialog = new JDialog(jbpci ,"Start donwloading...");
        JProgressBar progressBar = new JProgressBar(JProgressBar.HORIZONTAL);
        progressBar.setIndeterminate(true);
        downloadingDialog.setLayout(new FlowLayout(FlowLayout.LEFT));
        downloadingDialog.add(progressBar);
        downloadingDialog.setLocation(jbpci.getLocationOnScreen().x + jbpci.getWidth() / 2, jbpci.getLocationOnScreen().y + jbpci.getHeight() / 2);
        downloadingDialog.setSize(300, 100);
        downloadingDialog.setVisible(true);

Answer 1

我将你的代码包装在一个类中并删除了对jbpci的引用，它运行正常：

import javax.swing.*;
import java.awt.*;
public class t {

    public static void main(String[] args) {
        JDialog downloadingDialog = new JDialog((JFrame)null ,"Start donwloading...");
        JProgressBar progressBar = new JProgressBar(JProgressBar.HORIZONTAL);
        progressBar.setIndeterminate(true);
        downloadingDialog.setLayout(new FlowLayout(FlowLayout.LEFT));
        downloadingDialog.add(progressBar);
        downloadingDialog.setSize(300, 100);
        downloadingDialog.setVisible(true);
    }
}