本文目錄一覽：
Java中如何實現進度條效果
import java.awt.Color; import java.awt.Toolkit; import javax.swing.ImageIcon; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JProgressBar; import javax.swing.JWindow; @SuppressWarnings(“serial”) public class Demo extends JWindow implements Runnable { // 定義載入窗口大小 public static final int LOAD_WIDTH = 455; public static final int LOAD_HEIGHT = 295; // 獲取屏幕窗口大小 public static final int WIDTH = Toolkit.getDefaultToolkit().getScreenSize().width; public static final int HEIGHT = Toolkit.getDefaultToolkit().getScreenSize().height; // 定義進度條組件 public JProgressBar progressbar; // 定義標籤組件 public JLabel label; // 構造函數 public Demo() { // 創建標籤,並在標籤上放置一張圖片 label = new JLabel(new ImageIcon(“images/background.jpg”)); label.setBounds(0, 0, LOAD_WIDTH, LOAD_HEIGHT – 15); // 創建進度條 progressbar = new JProgressBar(); // 顯示當前進度值信息 progressbar.setStringPainted(true); // 設置進度條邊框不顯示 progressbar.setBorderPainted(false); // 設置進度條的前景色 progressbar.setForeground(new Color(0, 210, 40)); // 設置進度條的背景色 progressbar.setBackground(new Color(188, 190, 194)); progressbar.setBounds(0, LOAD_HEIGHT – 15, LOAD_WIDTH, 15); // 添加組件 this.add(label); this.add(progressbar); // 設置布局為空 this.setLayout(null); // 設置窗口初始位置 this.setLocation((WIDTH – LOAD_WIDTH) / 2, (HEIGHT – LOAD_HEIGHT) / 2); // 設置窗口大小 this.setSize(LOAD_WIDTH, LOAD_HEIGHT); // 設置窗口顯示 this.setVisible(true); } public static void main(String[] args) { Demo t = new Demo(); new Thread(t).start(); } @Override public void run() { for (int i = 0; i 100; i++) { try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } progressbar.setValue(i); } JOptionPane.showMessageDialog(this, “載入完成”); this.dispose(); } }
JAVA 進度條
直接上官方示例
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.beans.*;
import java.util.Random;
public class ProgressBarDemo extends JPanel
implements ActionListener,
PropertyChangeListener {
private JProgressBar progressBar;
private JButton startButton;
private JTextArea taskOutput;
private Task task;
class Task extends SwingWorkerVoid, Void {
/*
* Main task. Executed in background thread.
*/
@Override
public Void doInBackground() {
Random random = new Random();
int progress = 0;
//Initialize progress property.
setProgress(0);
while (progress 100) {
//Sleep for up to one second.
try {
Thread.sleep(random.nextInt(1000));
} catch (InterruptedException ignore) {}
//Make random progress.
progress += random.nextInt(10);
setProgress(Math.min(progress, 100));
}
return null;
}
/*
* Executed in event dispatching thread
*/
@Override
public void done() {
Toolkit.getDefaultToolkit().beep();
startButton.setEnabled(true);
setCursor(null); //turn off the wait cursor
taskOutput.append(“Done!\n”);
}
}
public ProgressBarDemo() {
super(new BorderLayout());
//Create the demo’s UI.
startButton = new JButton(“Start”);
startButton.setActionCommand(“start”);
startButton.addActionListener(this);
progressBar = new JProgressBar(0, 100);
progressBar.setValue(0);
progressBar.setStringPainted(true);
taskOutput = new JTextArea(5, 20);
taskOutput.setMargin(new Insets(5,5,5,5));
taskOutput.setEditable(false);
JPanel panel = new JPanel();
panel.add(startButton);
panel.add(progressBar);
add(panel, BorderLayout.PAGE_START);
add(new JScrollPane(taskOutput), BorderLayout.CENTER);
setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
}
/**
* Invoked when the user presses the start button.
*/
public void actionPerformed(ActionEvent evt) {
startButton.setEnabled(false);
setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
//Instances of javax.swing.SwingWorker are not reusuable, so
//we create new instances as needed.
task = new Task();
task.addPropertyChangeListener(this);
task.execute();
}
/**
* Invoked when task’s progress property changes.
*/
public void propertyChange(PropertyChangeEvent evt) {
if (“progress” == evt.getPropertyName()) {
int progress = (Integer) evt.getNewValue();
progressBar.setValue(progress);
taskOutput.append(String.format(
“Completed %d%% of task.\n”, task.getProgress()));
}
}
/**
* Create the GUI and show it. As with all GUI code, this must run
* on the event-dispatching thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame(“ProgressBarDemo”);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
JComponent newContentPane = new ProgressBarDemo();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application’s GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
java 做進度條 進度數據獲取
實現這個功能比較簡單，用到的類有兩個：ProgressMonitorInputStream（主要是整個類） 和 ProgressMonitor ，在javax.swing中整個文件的大小，和當前已經讀取文件的大小，獲得整個文件大小的方法
代碼如下:
ProgressMonitorInputStream monitor;
/**
* @param 表示此進度條要依附在哪個組件上
* @param 顯示在此進度條上的消息
* @param 需要監控的輸入流
*/
monitor = new ProgressMonitorInputStream(null, “Loading “,new FileInputStream(“filename path”));
int all = monitor.available();//整個文件的大小
int in = monitor.read(data);//每次讀取文件的大小
例如：你每次讀一行str=in.readLine();則data=str.instr.getBytes()+1;這裡+1，主要是為了獲得換行符的位元組數，否則，最後獲得的進步無法達到100%
代碼如下:
int readed=0;//表示已經讀取的文件
reader+=in;//累加讀取文件大小
計算進度：
代碼如下:
float process = (float) readed / all * 100;// 算出百分比
窗口顯示：
代碼如下:
progressMonitor.setNote(“archived ” + process + ” %”);// 顯示在進度條上
用 java 怎麼做進度條？
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
public class MyProgressBar extends Canvas {
private float scaleSize;
private float currentValue;
public MyProgressBar() {
this(100, 50);
}
public MyProgressBar(float scaleSize, float currentValue) {
this.scaleSize = scaleSize;
this.currentValue = currentValue;
this.setBackground(Color.lightGray);
this.setForeground(Color.magenta);
setSize(150, 25);
}
public float getCurrentValue() {
return currentValue;
}
public void setCurrentValue(float currentValue) {
this.currentValue = Math.max(0, currentValue);
if (this.scaleSize this.currentValue) {
this.currentValue = this.scaleSize;
}
}
public float getScaleSize() {
return scaleSize;
}
public void setScaleSize(float scaleSize) {
this.scaleSize = Math.max(1.0f, scaleSize);
if (this.scaleSize this.currentValue) {
this.scaleSize = this.currentValue;
}
}
public synchronized void paint(Graphics g) {
int w = getSize().width;
int h = getSize().height;
g.setColor(getBackground());
g.fillRect(1, 1, w – 2, h – 2);
g.fill3DRect(0, 0, w – 1, h – 1, true);
g.setColor(getForeground());
g.fillRect(3, 3, (int) (currentValue * (w – 6) / scaleSize), h – 6);
}
}
下面是程序執行入口點：
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
public class TestMyProgressBar extends JFrame implements Runnable,
ActionListener {
private MyProgressBar bar;
private JButton btnStart;
static TestMyProgressBar tmpb;
public TestMyProgressBar() {
setSize(400, 300);
setLocation(400, 400);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle(“演示自定義進度條”);
setLayout(new FlowLayout());
btnStart = new JButton(“開始”);
this.add(btnStart);
btnStart.addActionListener(this);
bar = new MyProgressBar();
setVisible(true);
}
public static void main(String[] args) {
tmpb = new TestMyProgressBar();
}
@Override
public void run() {
for (int i = 1; i = 20; i++) {
int x = i * 5;
bar.setCurrentValue(x);
if (x 0 x 100) {
btnStart.setEnabled(false);
}
if (x == 100) {
btnStart.setEnabled(true);
}
try {
Thread.sleep(200);
add(bar);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
@Override
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals(“開始”)) {
Thread t = new Thread(tmpb);
t.start();
}
}
}
java多線程導出如何更新進度條
1:一個子進程進行計算
2:計算過程中返回計算的百分比，比如10%，20%。。。。。100%；
3:前端需要一個定時器不斷請求進度，然後更新進度條。
原創文章，作者：小藍，如若轉載，請註明出處：https://www.506064.com/zh-tw/n/305118.html
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