i've discovered this test project from Oracle site because i want to add a circular progress bar in my project.
I'm developing the application with Netbeans, and when i start the application, the JPanel where the circle should be.... disappaer.
I've removed all the code that is not useful to solve this problem and i've got this code:
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import javax.swing.*;
import javax.swing.plaf.LayerUI;
public class Loading_Test extends javax.swing.JFrame
{
static final WaitLayerUI layerUI = new WaitLayerUI();
public Loading_Test()
{
JPanel panel = new JPanel();
JLayer<JPanel> jlayer = new JLayer<>(panel, layerUI);
add(jlayer);
initComponents();
}
@SuppressWarnings("unchecked")
private void initComponents() {
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 400, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 300, Short.MAX_VALUE)
);
pack();
}
public static void main(String args[])
{
java.awt.EventQueue.invokeLater(new Runnable()
{
@Override
public void run()
{
JFrame frame = new Loading_Test();
frame.setVisible(true);
layerUI.start();
}
});
}
}
class WaitLayerUI extends LayerUI<JPanel> implements ActionListener
{
private boolean mIsRunning;
private boolean mIsFadingOut;
private Timer mTimer;
private int mAngle;
private int mFadeCount;
private int mFadeLimit = 15;
@Override
public void paint(Graphics g, JComponent c)
{
int w = c.getWidth();
int h = c.getHeight();
// Paint the view.
super.paint(g, c);
if (!mIsRunning)
{
return;
}
Graphics2D g2 = (Graphics2D) g.create();
float fade = (float) mFadeCount / (float) mFadeLimit;
// Gray it out.
Composite urComposite = g2.getComposite();
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, .5f * fade));
g2.fillRect(0, 0, w, h);
g2.setComposite(urComposite);
// Paint the wait indicator.
int s = Math.min(w, h) / 5;
int cx = w / 2;
int cy = h / 2;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.setStroke(new BasicStroke(s / 4, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
g2.setPaint(Color.white);
g2.rotate(Math.PI * mAngle / 180, cx, cy);
for (int i = 0; i < 12; i++)
{
float scale = (11.0f - (float) i) / 11.0f;
g2.drawLine(cx + s, cy, cx + s * 2, cy);
g2.rotate(-Math.PI / 6, cx, cy);
g2.setComposite(AlphaComposite.getInstance(
AlphaComposite.SRC_OVER, scale * fade));
}
g2.dispose();
}
@Override
public void actionPerformed(ActionEvent e)
{
if (mIsRunning)
{
firePropertyChange("tick", 0, 1);
mAngle += 3;
if (mAngle >= 360)
{
mAngle = 0;
}
if (mIsFadingOut)
{
if (--mFadeCount == 0)
{
mIsRunning = false;
mTimer.stop();
}
}
else if (mFadeCount < mFadeLimit)
{
mFadeCount++;
}
}
}
public void start()
{
if (mIsRunning)
{
return;
}
// Run a thread for animation.
mIsRunning = true;
mIsFadingOut = false;
mFadeCount = 0;
int fps = 24;
int tick = 1000 / fps;
mTimer = new Timer(tick, this);
mTimer.start();
}
public void stop()
{
mIsFadingOut = true;
}
@Override
public void applyPropertyChange(PropertyChangeEvent pce, JLayer l)
{
if ("tick".equals(pce.getPropertyName()))
{
l.repaint();
}
}
}
If you run this code "as is", you should have the same my problem, the JPanel is not shown.
But i've discovered that if i remove the layout-related lines (27~36) the progress bar starts to work.
You also have to set manually the windows size adding
setSize(300, 300);
after
pack();
Because the layout-lines are automatically generated by Netbeans, i'm trying to understand how to solve this problem, because this particular lines of code are blocked for editing by Netbeans Editor.
I've lost one day and it still not working.... I'll use an animated gif on JLabel.... End of story!
@Robin has important info, and seems like as you limited by usage of GuiBulder..., then I'm don't want to comment something, result is
from little bit modified code
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import javax.swing.*;
import javax.swing.plaf.LayerUI;
public class Loading_Test {
static final WaitLayerUI layerUI = new WaitLayerUI();
JFrame frame = new JFrame("JLayer With Animated Gif");
public Loading_Test() {
JPanel panel = new JPanel() {
@Override
public Dimension getPreferredSize() {
return new Dimension(400, 300);
}
};
JLayer<JPanel> jlayer = new JLayer<>(panel, layerUI);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(jlayer);
frame.pack();
frame.setVisible(true);
layerUI.start();
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
Loading_Test loading_Test = new Loading_Test();
}
});
}
}
class WaitLayerUI extends LayerUI<JPanel> implements ActionListener {
private boolean mIsRunning;
private boolean mIsFadingOut;
private Timer mTimer;
private int mAngle;
private int mFadeCount;
private int mFadeLimit = 15;
@Override
public void paint(Graphics g, JComponent c) {
int w = c.getWidth();
int h = c.getHeight();
super.paint(g, c); // Paint the view.
if (!mIsRunning) {
return;
}
Graphics2D g2 = (Graphics2D) g.create();
float fade = (float) mFadeCount / (float) mFadeLimit;
Composite urComposite = g2.getComposite(); // Gray it out.
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, .5f * fade));
g2.fillRect(0, 0, w, h);
g2.setComposite(urComposite);
int s = Math.min(w, h) / 5;// Paint the wait indicator.
int cx = w / 2;
int cy = h / 2;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2.setStroke(new BasicStroke(s / 4, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
g2.setPaint(Color.white);
g2.rotate(Math.PI * mAngle / 180, cx, cy);
for (int i = 0; i < 12; i++) {
float scale = (11.0f - (float) i) / 11.0f;
g2.drawLine(cx + s, cy, cx + s * 2, cy);
g2.rotate(-Math.PI / 6, cx, cy);
g2.setComposite(AlphaComposite.getInstance(
AlphaComposite.SRC_OVER, scale * fade));
}
g2.dispose();
}
@Override
public void actionPerformed(ActionEvent e) {
if (mIsRunning) {
firePropertyChange("tick", 0, 1);
mAngle += 3;
if (mAngle >= 360) {
mAngle = 0;
}
if (mIsFadingOut) {
if (--mFadeCount == 0) {
mIsRunning = false;
mTimer.stop();
}
} else if (mFadeCount < mFadeLimit) {
mFadeCount++;
}
}
}
public void start() {
if (mIsRunning) {
return;
}
mIsRunning = true;// Run a thread for animation.
mIsFadingOut = false;
mFadeCount = 0;
int fps = 24;
int tick = 1000 / fps;
mTimer = new Timer(tick, this);
mTimer.start();
}
public void stop() {
mIsFadingOut = true;
}
@Override
public void applyPropertyChange(PropertyChangeEvent pce, JLayer l) {
if ("tick".equals(pce.getPropertyName())) {
l.repaint();
}
}
}
have to add two
JButtons, one for start and second for stop (show and hide animated Gig)don't forger that
JPanelhas implementedFlowLayout, that pretty acceptingPreferredSizecame from its childs,
Found a better simple (and working) solution with Swing Components Extension by SwingLabs
JXBusyLabel
There is a fully integrating plugin with NetBeans for its editor, so is very simple to use
It seems from your question and comments you are having problems implementing the JLayer in Netbeans, I'd suggest then rather going for a CardLayout which will allow you to switch between your normal JPanel and the one with the spinner.
Here is a simple tutorial: CardLayout With Netbeans
来源：https://stackoverflow.com/questions/11846589/circular-progress-bar-for-java-swing-not-working