Make button change color when mouse moves over it
I am trying to make the color of my exit button ( jButtonExit )change when I move a mouse over it ( aka I'm playing with events ). I have the following event handler that makes my program not compile. What am I doing wrong?
private void jButtonExitMouseEntered(java.awt.event.MouseEvent evt) {
jButtonExit.setBackground(Color.BLUE);
}
Bart Cremers
The code snippet you provide should compile. You'll need to provide more code to show the problem.
ASKER
Bart Cr,
I am trying to learn NetBeans while I learn Java. This code comes from following the NetBeans help files. I'm telling you this to let you know I don't understand which files are important. I zipped my entire directory for you but I think EE won't let me include my .java file in the archive ( I think it;s the most important one ). Here it is below: ( tell me if you need more )
I am trying to learn NetBeans while I learn Java. This code comes from following the NetBeans help files. I'm telling you this to let you know I don't understand which files are important. I zipped my entire directory for you but I think EE won't let me include my .java file in the archive ( I think it;s the most important one ). Here it is below: ( tell me if you need more )
/*
* NumberAdditionUI.java
*
* Created on November 8, 2008, 8:06 AM
*/
package my.numberaddition;
/**
*
* @author dwcronin
*/
public class NumberAdditionUI extends javax.swing.JFrame
{
/** Creates new form NumberAdditionUI */
public NumberAdditionUI()
{
initComponents();
}
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanel1 = new javax.swing.JPanel();
jLabelFirstNumber = new javax.swing.JLabel();
jLabelResult = new javax.swing.JLabel();
jLabelSecondNumber = new javax.swing.JLabel();
jTextFieldFirstNumber = new javax.swing.JTextField();
jTextFieldSecondNumber = new javax.swing.JTextField();
jTextFieldResult = new javax.swing.JTextField();
jButtonAdd = new javax.swing.JButton();
jButtonClear = new javax.swing.JButton();
jLabel1 = new javax.swing.JLabel();
jButtonExit = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setBorder(javax.swing.BorderFactory.createTitledBorder("Number Addition"));
jLabelFirstNumber.setText("First Number");
jLabelResult.setText("Result");
jLabelSecondNumber.setText("Second Number");
jTextFieldFirstNumber.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jTextFieldFirstNumberActionPerformed(evt);
}
});
jButtonAdd.setText("Add");
jButtonAdd.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonAddActionPerformed(evt);
}
});
jButtonClear.setText("Clear");
jButtonClear.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonClearActionPerformed(evt);
}
});
jLabel1.setText("jLabel1");
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabelFirstNumber, javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jLabelSecondNumber, javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jLabelResult, javax.swing.GroupLayout.Alignment.TRAILING))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addGroup(jPanel1Layout.createSequentialGroup()
.addComponent(jButtonAdd)
.addGap(41, 41, 41)
.addComponent(jButtonClear))
.addComponent(jTextFieldFirstNumber, javax.swing.GroupLayout.DEFAULT_SIZE, 290, Short.MAX_VALUE)
.addComponent(jTextFieldSecondNumber)
.addComponent(jTextFieldResult)))
.addComponent(jLabel1))
.addContainerGap())
);
jPanel1Layout.linkSize(javax.swing.SwingConstants.HORIZONTAL, new java.awt.Component[] {jButtonAdd, jButtonClear});
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabelFirstNumber)
.addComponent(jTextFieldFirstNumber, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabelSecondNumber)
.addComponent(jTextFieldSecondNumber, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(3, 3, 3)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabelResult)
.addComponent(jTextFieldResult, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(46, 46, 46)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButtonAdd)
.addComponent(jButtonClear)))
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(51, 51, 51)
.addComponent(jLabel1)))
.addContainerGap(30, Short.MAX_VALUE))
);
jButtonExit.setText("Exit");
jButtonExit.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseEntered(java.awt.event.MouseEvent evt) {
jButtonExitMouseEntered(evt);
}
});
jButtonExit.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButtonExitActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButtonExit, javax.swing.GroupLayout.Alignment.TRAILING))
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(24, 24, 24)
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jButtonExit)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void jButtonClearActionPerformed(java.awt.event.ActionEvent evt) {
jTextFieldFirstNumber.setText("");
jTextFieldSecondNumber.setText("");
jTextFieldResult.setText("");
}
private void jButtonExitActionPerformed(java.awt.event.ActionEvent evt) {
System.exit(0);
}
private void jTextFieldFirstNumberActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void jButtonAddActionPerformed(java.awt.event.ActionEvent evt) {
// First we define float variables.
float num1, num2, result;
// We have to parse the text to a type float.
num1 = Float.parseFloat(jTextFieldFirstNumber.getText());
num2 = Float.parseFloat(jTextFieldSecondNumber.getText());
// Now we can perform the addition.
result = num1 + num2;
// We will now pass the value of result to jTextField3.
// At the same time, we are going to
// change the value of result from a float to a string.
jTextFieldResult.setText(String.valueOf(result));
}
private void jButtonExitMouseEntered(java.awt.event.MouseEvent evt) {
jButtonExit.setBackground(Color.BLUE);
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new NumberAdditionUI().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButtonAdd;
private javax.swing.JButton jButtonClear;
private javax.swing.JButton jButtonExit;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabelFirstNumber;
private javax.swing.JLabel jLabelResult;
private javax.swing.JLabel jLabelSecondNumber;
private javax.swing.JPanel jPanel1;
private javax.swing.JTextField jTextFieldFirstNumber;
private javax.swing.JTextField jTextFieldResult;
private javax.swing.JTextField jTextFieldSecondNumber;
// End of variables declaration
}ASKER CERTIFIED SOLUTION
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ASKER
I think what Bart Cr said is right. The import MAY have already been there though and I was just getting impatient. When I got out of netbeans and restarted it - it worked properly and I don't think I added the line (it was already in my code). It just needed (???) restarting. Sorry - I don't know what just happened.