如何将JProgressBar添加到JDialog

Question

I'm trying to add JProgressBar to JDialog but JProgressBar never show up. Below is my code. Any help?

        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

I wrapped your code in a class and removed references to jbpci, and it works fine:

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);
    }
}