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JProgressBar由UI委托

BasicProgressBarUI指定.下面的示例说明了各种布局管理器的效果. FlowLayout只使用UIManager默认值ProgressBar.horizo​​ntalSize,而GridLayout和BorderLayout.CENTER填充可用空间.带有侧面胶水的BoxLayout可在调整框架大小时按比例调整.

I am already using a SwingWorker

从SwingWorker的process()方法更新GUI应该是安全的.您可以更改图层甚至删除组件,但我会对过于复杂的事情保持警惕.

附录：这是相关的默认值.

System.out.println(UIManager.get("ProgressBar.horizontalSize"));

javax.swing.plaf.DimensionUIResource[width=146,height=12]

码：

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.EventQueue;

import java.awt.FlowLayout;

import java.awt.GridLayout;

import java.awt.LayoutManager;

import javax.swing.BorderFactory;

import javax.swing.Box;

import javax.swing.BoxLayout;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JProgressBar;

/** @see https://stackoverflow.com/questions/7256775 */

public class ProgressTest {

private static final Color border = Color.gray;

private static void display() {

JFrame f = new JFrame("ProgressTest");

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

f.setLayout(new GridLayout(0, 1));

f.add(createPanel(new FlowLayout()));

f.add(createPanel(new GridLayout()));

f.add(createPanel(new BorderLayout()));

JPanel p = new JPanel();

p.setLayout(new BoxLayout(p, BoxLayout.X_AXIS));

p.setBorder(BorderFactory.createLineBorder(border));

JProgressBar jpb = new JProgressBar();

p.add(Box.createHorizontalGlue());

p.add(jpb);

p.add(Box.createHorizontalGlue());

jpb.setIndeterminate(true);

f.add(p);

f.pack();

f.setSize(320, 240);

f.setLocationRelativeTo(null);

f.setVisible(true);

}

private static JPanel createPanel(LayoutManager layout) {

JPanel p = new JPanel();

p.setBorder(BorderFactory.createLineBorder(border));

p.setLayout(layout);

JProgressBar jpb = new JProgressBar();

jpb.setIndeterminate(true);

p.add(jpb);

return p;

}

public static void main(String[] args) {

EventQueue.invokeLater(new Runnable() {

@Override

public void run() {

display();

}

});

}

}