Installing something hosted or invisible java
changed the project since its inception. like. the image still doesn't change.
package icnon;
import javax.imageio.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class FrameIconExample extends JFrame implements ActionListener {
JLabel j;
JPanel p, l, k;
JButton picOne, picTwo;
Container cPane;
public FrameIconExample() {
JButton picOne = new JButton("picOne");
JButton picTwo = new JButton("picTwo");
picOne.setName("picOne");
picTwo.setName("picTwo");
picOne.addActionListener(this);
picTwo.addActionListener(this);
p = new JPanel(new GridLayout(2, 1));
l = new JPanel(new FlowLayout());
k = new JPanel(new FlowLayout());
cPane = getContentPane();
j = new JLabel(new ImageIcon(
"../meet/src/images/beautiful-closeup-portrait-photography.jpg"));
l.add(j);
k.add(picOne);
k.add(picTwo);
p.add(l);
p.add(k);
add(p);
}
public static void main(String[] args) {
FrameIconExample frame = new FrameIconExample();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(new Dimension(300, 800));
frame.setTitle("Frame Icon Example");
// Display the form
frame.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent e) {
JButton temp = (JButton) e.getSource();
String src = "../meet/src/images/Majken Kruse portrait - john.jpg";
//System.out.println(src + " " + temp.getName());
if (temp.getName().equalsIgnoreCase("picOne")) {
try {
l.hide();
try {
src = "../meet/src/images/beautiful-closeup-portrait-photography.jpg";
System.out.println(src + " " + temp.getName());
Icon img;
j = new JLabel(new ImageIcon(src));
l.add(j);
System.out.println("1");
} catch (Exception q) {
q.printStackTrace();
}
if (temp.getName().equalsIgnoreCase("picTwo")) {
src = "../icontest/images/Majken Kruse portrait - john.jpg";
System.out.println(src + " " + temp.getName());
Icon img;
j = new JLabel(new ImageIcon(src));
l.add(j);
System.out.println("2");
}
} catch (Exception x) {
x.printStackTrace();
}
}
}
}
Sorry for the bad indentation. im sure the method l.add (j); the reason the image doesn't change.
any ideas what it should be?
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Note: This answer was made for revisions of questions 1 and 2.
This is not an Awt error, it is a NullPointerException.
Your l field is null because the moment you thought you created it, you actually masked it with a local variable.
JPanel p = new JPanel(new GridLayout(2, 1));
JPanel l = new JPanel(new FlowLayout());
JPanel k = new JPanel(new FlowLayout());
Should be:
p = new JPanel(new GridLayout(2, 1));
l = new JPanel(new FlowLayout());
k = new JPanel(new FlowLayout());
Read the stack trace error again. It tells you which line is the problem and the type of error tells you what happened in that case.
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The problem is that you are declaring a global JPanel
named l
, but then when you instantiate JPanel
in your constructor, you are declaring and assigning a local JPanel
named scope l
. When you try to add a component to yours actionPerformed
, you try to add it to the global var null
.
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