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.
initComponents
call and theadd(jlayer)
call ? I wouldn't be surprised if your calls in theinitComponents
mess with theJLayer
you already added to the frame – BesiegegetContentPane().setLayout(layout);
is the problem. If I comment it, the loading is shown. – Redwood