在操作后显示进度条

Question

我想在一些操作后显示一个进度条。实际代码很复杂，但我准备了一个示例我希望进度条填满框架的宽度，但我希望它具有 specific/normal 高度而不填满框架。我怎样才能做到这一点？如果框架的布局没有改变 (BorderLayout) 会更好，因为它可能会破坏我的实际代码中的其他内容。如果这无法避免，那么一定要改变它，我会看看结果如何。

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
import javax.swing.Timer;

public class SwingControlDemo
{

    public static int progress = 0;
    private JFrame mainFrame;

    public SwingControlDemo()
    {
        prepareGUI();
    }

    public static void main(String[] args)
    throws Exception
    {
        //BeautyEyeLNFHelper.frameBorderStyle = BeautyEyeLNFHelper.FrameBorderStyle.osLookAndFeelDecorated;
       // org.jb2011.lnf.beautyeye.BeautyEyeLNFHelper.launchBeautyEyeLNF();
        new SwingControlDemo();
    }

    private void prepareGUI()
    {
        mainFrame = new JFrame("Java Swing Examples");
        mainFrame.setSize(400, 400);
        mainFrame.setLayout(new BorderLayout());
        mainFrame.addWindowListener(new WindowAdapter()
        {
            public void windowClosing(WindowEvent windowEvent)
            {
                System.exit(0);
            }
        });
        JButton startButton = new JButton("Start");
        startButton.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                showProgressBarDemo();
            }
        });

        mainFrame.add(new JLabel("mplaaaaaaaaaaaaaaaaaaa"), BorderLayout.CENTER);
        mainFrame.add(startButton, BorderLayout.SOUTH);
        mainFrame.setVisible(true);
    }

    private void showProgressBarDemo()
    {
        final JProgressBar progressBar = new JProgressBar(0, 100);
        progressBar.setValue(0);
        progressBar.setStringPainted(true);

        JPanel controlPanel = new JPanel();
        controlPanel.setLayout(new BorderLayout());
        controlPanel.add(progressBar, BorderLayout.CENTER);

        mainFrame.add(controlPanel);
        mainFrame.revalidate();
        mainFrame.repaint();

        final Timer timer = new Timer(1000, new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {   
                progress++;
                System.out.println(String.format("Completed %d%% of task.\n", progress));
                progressBar.setValue(progress);
                progressBar.setString(String.format("Completed %d%% of task.\n", progress));
            }
        });

        timer.start();
    }
}

Answer 1

but I want it to have a specific/normal height

如果您希望它在其 preferredSize 处显示，而不是将其添加到使用 FlowLayout 的 JPanel，然后将该 JPanel 添加到您的 BorderLayout-using JPanel（如果您仍想保留 BorderLayout ).请注意，我会使用 CardLayout 交换组件。

Answer 2

The actual code is complex, but I've prepared a sample I want the progress bar to fill the width of the frame, but I want it to have a specific/normal height and not fill the frame.

您可以使用 GridBagLayout，例如

JPanel controlPanel = new JPanel();
controlPanel.setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.weightx = 1;
gbc.fill = GridBagConstraints.HORIZONTAL;
controlPanel.add(progressBar, gbc);

有关详细信息，请参阅 How to Use GridBagLayout

您可以考虑利用框架的 "glass pane"，这样您就可以将内容放在 contentPane 的顶部，但不会直接影响它。如果你向它注册了一个 MouseListener，你甚至可以阻止鼠标事件到达 contentPane 本身。

查看 How to Use Root Panes 了解更多详情

此外，根据您的需要，您或许可以使用 ProgressMonitor、for example

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