Swing顯示標準進度條範例

2019-10-16 22:05:15

以下範例展示了如何在Java Swing應用程式中顯示標準進度條。

使用以下API -

  • JProgressBar - 建立進度條欄位。
  • JProgressBar.setValue - 設定進度條中的進度。

範例

package com.yiibai.swingdemo;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class SwingTester {
    private JFrame mainFrame;
    private JLabel headerLabel;
    private JLabel statusLabel;
    private JPanel controlPanel;

    public SwingTester() {
        prepareGUI();
    }

    public static void main(String[] args) {
        SwingTester swingControlDemo = new SwingTester();
        swingControlDemo.showProgressBarDemo();
    }

    private void prepareGUI() {
        mainFrame = new JFrame("Swing顯示標準進度條範例");
        mainFrame.setSize(400, 400);
        mainFrame.setLayout(new GridLayout(3, 1));

        mainFrame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent windowEvent) {
                System.exit(0);
            }
        });
        headerLabel = new JLabel("", JLabel.CENTER);
        statusLabel = new JLabel("", JLabel.CENTER);
        statusLabel.setSize(350, 100);

        controlPanel = new JPanel();
        controlPanel.setLayout(new FlowLayout());

        mainFrame.add(headerLabel);
        mainFrame.add(controlPanel);
        mainFrame.add(statusLabel);
        mainFrame.setVisible(true);
    }

    private JProgressBar progressBar;
    private Task task;
    private JButton startButton;
    private JTextArea outputTextArea;

    private void showProgressBarDemo() {
        headerLabel.setText("Control in action: JProgressBar");
        progressBar = new JProgressBar(0, 100);
        progressBar.setValue(0);
        progressBar.setStringPainted(true);
        startButton = new JButton("開始...");
        outputTextArea = new JTextArea("", 5, 20);
        JScrollPane scrollPane = new JScrollPane(outputTextArea);

        startButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                task = new Task();
                task.start();
            }
        });
        controlPanel.add(startButton);
        controlPanel.add(progressBar);
        controlPanel.add(scrollPane);
        mainFrame.setVisible(true);
    }

    private class Task extends Thread {
        public Task() {
        }

        public void run() {
            for (int i = 0; i <= 100; i += 10) {
                final int progress = i;

                SwingUtilities.invokeLater(new Runnable() {
                    public void run() {
                        progressBar.setValue(progress);
                        outputTextArea.setText(
                                outputTextArea.getText() + String.format("任務已完成 %d%% .\n", progress));
                    }
                });
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                }
            }
        }
    }
}

執行上面範例程式碼,得到以下結果: