Develop Reference

How do I hide a jButton after it has been clicked in a jPanel

Can anyone help me with my issue? I can't seem to figure out how I can make a jButton hide after it has been clicked ONCE.
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
//The hide code would go here
}

you are looking for
jButton1.setVisible(false);

First of all, just use implement interface actionListener to your class:
public class test implements ActionListener {
Next, add actionListener to your button:
button.addActionListener(this);
Last in the implemented actionPerformed method:
public void actionPerformed(ActionEvent e){
if(e.getSource.equals(button)) button.setVisible(false); //set's the buttons visibility to false.
}
**Edit: If you want to do it for one button click, in the actionPerformed method if statement you can also do: **
public void actionPerformed(ActionEvent e){
if(e.getSource.equals(button) && !once){
button.setVisible(false);
once = true; //once is a boolean which shows if the button has been clicked once
}
}
Hope this helps.

Closing JFrame with a JButton

Im having problem with this code , it doesn't compile . Could you help me ?
I need to close the JFrame when i click the button
public class SlotMachine extends JFrame
{
/*
*
*/
JButton btnExit = new JButton("Exit");
btnExit.addMouseListener(new MouseAdapter()
{
#Override
public void mouseClicked(MouseEvent arg0)
{
this.dispose();
}
});
}
The error is = The method dispose() is undefined for the type new MouseAdapter(){}
I dont know how to get the SlotMachine object from the mouseClicked method

You're calling this.dispose(); the key here being that this refers to the inner class, the MouseListener, and MouseListener doesn't have a dispose() method.
Solution: get rid of this, and it should work, since the compiler will then look into the outer class if the inner class does not contain the method. Alternatively you could specify which this you mean: SlotMachine.this.dispose(); will tell the compiler to call the method of the outer SlotMachine class.
Use an ActionListener on a JButton for several reasons:
Default behavior of buttons is to be activated by spacebar press if the button has focus. This will not work for a MouseListener.
Also an expected behavior is that if the button is disabled via setEnabled(false), then pressing it should not cause the action to be fired. This does not work with MouseListener but does with ActionListener.
You can easily share the ActionListener (or better yet, an AbstractAction) with other components including JMenuItems.

how to make a button run a loop in java

I understand how to create a button and it's application in Java. Would anyone be able to show me the code to be able to make the button in the code below be able to print something as simple as hello world in the terminal. I am using bluej if that is of any matter. I am very sorry I am a beginner coder.

JButton button = new JButton();
button.setActionListener(e -> System.out.println("Clicked"));
This uses a lambda expression. Inside it, you can add as much code as you like, but add it between {} if it's more than a line.
More on buttons here

You need a listener for your button.
JButton button= new JButton("Button");
button.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.out.println("Hello World");
}
});
the button will 'listen' for the action and preform whatever task you define for it.

ActionListener is what you are looking for. There is a very nice guide on Oracle's website. You should look into this tutorial and understand different ways of creating ActionListeners. I will give you a simple example which doesn't involve Anonymous Classes because I am not sure of how much you know about them.
public class Frame extends JFrame implements ActionListener {
public Frame() {
super("Test"); // calling the superclass
setLayout(new FlowLayout()); // creating a layout for the frame
setDefaultCloseOperation(EXIT_ON_CLOSE);
// create the button
JButton jbTest = new JButton("Click me!");
/* 'this' refers to the instance of the class
because your class implements ActionListener
and you defined what to do in case a button gets pressed (see actionPerformed)
you can add it to the button
*/
jbTest.addActionListener(this);
add(jbTest);
pack();
}
// When a component gets clicked, do the following
#Override
public void actionPerformed(ActionEvent ae) {
System.out.println("Hello!");
}
}

ActionListener with a mousepress in java

I am trying to Make a action performed method activate when the mouse is pressed. is this possible. i can only find example like:
if(e.getsource() == button1){
....
}
can this method be activated by a mouseclick?

You could use a MouseListener to your component (and then call the actionListener from its mouse clicked event.
See: http://docs.oracle.com/javase/tutorial/uiswing/events/mouselistener.html
You may want to create a third function taking a JComponent source and having that containing your actionlistener code and being called by both your mouselistener and actionlistener.

You can try the following code...
This will just print "Hi" to terminal every time you click whatever you put the mouseListener on. Replace contentPane with whatever you called it, and don't forget your import statements.
contentPane.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent arg0) {
System.out.println("Hi");
}
});

ActionListener problem

I have a problem with my actionListener.
It seems that the actionListener runs automatically before I click the button?
The "This should not appear in the console before button click" appear in the console before I click the button".... This is strange.
....
button1.addActionListener(this);
button2.addActionListener(this);
....
public void actionPerformed(ActionEvent e) {
System.out.println("This should not appear in the console before button click");
if (e.getSource()==button1)
System.out.println ("answer1");
else if (e.getSource()==button2)
System.out.println ("answer2");
.....
}

You can tell where methods are being called from by calling Thread.dumpStack(). That will print the stack trace to the error stream (possibly the Java console). Alternatively use a debugger and place a break point on the first line of the method.
public void actionPerformed(ActionEvent e) {
Thread.duumpStack();
System.out.println("This should not appear in the console before button click");
...
BTW: I recommend not using EventObject.getSource. Instead add a new listener for every action.
So your example code would become:
button1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
System.out.println("answer1");
}
});
button2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent event) {
System.out.println("answer2");
}
});
Unfortunately the boilerplate associated with anonymous inner classes is distinctly verbose, but the intention is clearer.

Also make sure that you have not added 'this' as an ActionListener to any other components that might be use before you click either of the buttons. You could also search your code for doClick() calls to make sure you dont call it programatically.