Question

java怎么让进度条带百分数

Answer 1

你运行以下测试看看就知道了，
这是一个完整的进度条
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;
class ProgressBarDemo implements ActionListener, ChangeListener {
JFrame frame = null;
JProgressBar progressbar;
JLabel label;
Timer timer;
JButton b;
public ProgressBarDemo() {
frame = new JFrame("hoyo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container content = frame.getContentPane();
label = new JLabel(" ", JLabel.CENTER);
progressbar = new JProgressBar();// 创建一个进度条
progressbar.setOrientation(JProgressBar.HORIZONTAL);
progressbar.setMinimum(0);
progressbar.setMaximum(100);
progressbar.setValue(0);
progressbar.setStringPainted(true);
progressbar.addChangeListener(this);
progressbar.setPreferredSize(new Dimension(300, 20));
progressbar.setBorderPainted(true);
progressbar.setBackground(Color.pink);
JPanel panel = new JPanel();
b = new JButton("安装");
b.setForeground(Color.blue);// 添加事件监听
b.addActionListener(this);
panel.add(b);
timer = new Timer(100, this);
content.add(panel, BorderLayout.NORTH);
content.add(progressbar, BorderLayout.CENTER);
content.add(label, BorderLayout.SOUTH);
frame.pack();
frame.setVisible(true);
}
// 实现事件监听的方法
public void actionPerformed(ActionEvent e) {
if (e.getSource() == b)
timer.start();
if (e.getSource() == timer) {
int value = progressbar.getValue();
if (value < 100) {
progressbar.setValue(++value);
} else {
timer.stop();
frame.dispose();
}
}
}
public void stateChanged(ChangeEvent e1) {
int value = progressbar.getValue();
if (e1.getSource() == progressbar) {
label.setText("目前已完成进度:" + Integer.toString(value) + "%");
label.setForeground(Color.blue);
}
}
}
public class Process {
public static void main(String[] args) {
new ProgressBarDemo();
}
}

Answer 2

public void setString(String s)
设置进度字符串的值。默认情况下，此字符串为 null，隐含使用简单百分比字符串的内置行为。如果已提供自定义进度字符串并要转换回内置状态，将字符串设置回 null 即可。
仅当 isStringPainted 方法返回 true 时绘制进度字符串。

参数：
s - 进度字符串的值
另请参见：
getString(), setStringPainted(boolean), isStringPainted()

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 SwingWorker<Void, 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();
}
});
}
}

Answer 3

文字是根据自己计算的。

javax.swing.JProgressBar
setString

public void setString(String s)
设置进度字符串的值。默认情况下，此字符串为 null，隐含使用简单百分比字符串的内置行为。如果已提供自定义进度字符串并要转换回内置状态，将字符串设置回 null 即可。
仅当 isStringPainted 方法返回 true 时绘制进度字符串。

参数：
s - 进度字符串的值
另请参见：
getString(), setStringPainted(boolean), isStringPainted()

Answer 4

JProgressBar progressBar = new JProgressBar(0,size);
progressBar.setString("当前进度"+i/size);