I'm having some trouble figuring out how to make a JButton prompt the user to save the contents in a JTextArea before closing the program. So far, I have some code for the close operation for my button, but even that doesn't seem to work... nothing happens when I click it:
public void actionPerformed(ActionEvent event) {
if(event.getSource() == this.Quit)
this.dispose();
....
the rest are more else/if/try statements for other buttons.
I set my class to extend JFrame and implement ActionListener, so my entire program is in one class... probably not a very neat way to code, but I'm finding it easier to stick everything here for now before I distribute some functions into other classes.
Basically, nothing happens, and I don't know how to add the save prompt along with closing it afterwards. Any help would be great!
Is there any way to tie this into a prompt to save before closing?
See Closing an Application.
Note: you can also add the ExitAction to your JButton. Then when you click on the button it will initiate the closing of the window.
Try this:
MyClass.this.setVisible(false);
Also for a hard application exit do:
System.exit(0);
A more easy way to do what you want is this:
class MyClass extends JFrame{
public MyClass(){
JButton myButton;
//... etc
myButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent event){
MyClass.this.setVisible(false);
}
});
}
}
Related
I have my main JFrame and one more JDialog.
If user click on the button, i want JDialog to call method from this JFrame(which contains some operations on ComboBox in this JFrame).
How can I do that?
I don't want to use MyJFrame form = new MyJFrame(); because it will make a new JFrame which i don't want to do, i want to call method from JFrame which is running currently on my computer.
Thanks.
Assuming the JButton is on the JDialog.
If both are in the same class, why not just do this?
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
//I just got clicked
form.doSomething();
}
});
which can be shortened to
button.addActionListener(e -> form.doSomething());
If they aren't, and you're extending JDialog (which I wouldn't recommend) just pass the JFrame in its constructor, then your dialog will have access to it.
It's not possible to add much more without seeing more of your code.
Maybe JOptionPane.showInputDialog() , show a JDialog to take input from User.
I seem to have a fairly unique problem, and I searched for a while for an answer on here without finding one. I have a class that has a simple JFrame with two buttons. Each button calls the Main method of a different class, as such:
checkRuling = new JButton("Check Your Deck's Rulings");
checkRuling.addActionListener(new ActionListener() {
public void actionPerformed (ActionEvent e) {
ReadHtmlCardDatabase.main(null);
}
});
One calls a class that takes a series of inputs into a text field and creates a formatted html document from the inputs, and the other loads the html document into a JEditorPane. My problem is that when I close one of the JFrames for the subclasses (either the input or html loader one), it exits my program completely, and I want to keep the main class (with the two buttons) open. I've tried using:
close = new JButton("CLOSE");
close.addActionListener(new ActionListener() {
public void actionPerformed (ActionEvent e) {
System.exit(1);
}
});
On a button in the subclasses, to no avail. When the button is clicked it simply exits everything. I've also tried using:
JFrame.DISPOSE_ON_EXIT
For the subclasses, but this causes the JFrames to go away without the subclasses actually closing, so the first one that saves the html document never actually saves it, and the second subclass that opens that same html document won't work, because it wasn't saved. Any help would be appreciated, because I can't figure out how to do this.
As Fast Snail says in the comments, you shouldn't be calling a main method. Instantiate a class that does each functonality. Set the frame to visible using setVisible(true) when you start using it, then setVisible(false) when you're done. So, in the action listener, just change the visibility.
Then, assuming you don't have anything too wild going on, the frame you just set to invisible should go out of scope and get freed so that memory isn't chewed up. You just instantiate a new copy of the ReadHtmlCardDatabase class each time you need one. Or you could have one static copy that you set visible/invisible as needed.
one of the JFrames
You should use only one JFrame in Your GUI. For other windows You can use for example JDialog or JWindow.
This should help, if not You can always use frame.setVisible(false) instead of dispose on close, but it' s not very neat.
Thanks to someone who posted a comment and then deleted it, I've figured out my own problem. I just had to replace my main call with this:
setDeck = new JButton("Set Deck");
setDeck.addActionListener(new ActionListener() {
public void actionPerformed (ActionEvent e) {
WriteHtmlCardDatabase w = new WriteHtmlCardDatabase();
w.main(null);
}
});
Thank you!
I have written a calculator in NetBeans and it functions perfectly. However, I have to actually click the buttons to insert numbers and am trying to remedy that with a KeyListener. I have all my numbers and function buttons set inside a JPanel named buttons. I have my display label in a JPanel named display.
I set my class to implement KeyListener and it inserted the KeyPressed, -Typed, and -Released methods; however I stuck from there. I'm not sure how to make my buttons actually listen for the KeyPressed event, and when it hears the event - activate the button. Also, my buttons are named by their number (e.g. the Zero Button is named zero, One button is one, etc.).
I've read that you actually have to implement a KeyListener somewhere by using: something.addKeyListener(something);
but I cannot seem to figure this out.
Can I get some help here? I'm new to Java and this is my first solo project. And let me know if I didn't provide enough information.
EDIT: Most of my code is NetBeans Generated and I cannot edit the initialization of the components which seems to be my problem I think?
My class declaration:
public class Calculator extends javax.swing.JFrame implements KeyListener {
//Creates new form Calculator
public Calculator() {
initComponents();
}
One of my buttonPressed actions (all identical with changes for actual number):
private void zeroActionPerformed(java.awt.event.ActionEvent evt) {
if (display.getText().length() >= 16)
{
JOptionPane.showMessageDialog(null, "Cannot Handle > 16 digits");
return;
}
else if (display.getText().equals("0"))
{
return;
}
display.setText(display.getText().concat("0"));
Main method supplied by NetBeans:
public static void main(String args[]) {
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new Calculator().setVisible(true);
}
});
}
The initComponents() netbeans generated is absolutely massive (about 500 lines of code) and I cannot edit any of it. Let me know if I can supply any more helpful information.
Could there be an issue of Focus, and if so how can I resolve the issue?
Yes there is probably an issue with focus. That is why you should NOT be using a KeyListener.
Swing was designed to be used with Key Bindings. That is you create an Action that does what you want. Then this Action can be added to your JButton. It can also be bound to a KeyStroke. So you have nice reusable code.
Read the Swing tutorial on How to Use Key Bindings for more information. Key Bindings don't have the focus issue that you currently have.
I'm not sure I completely understand your question, and some code would help, but I'll take a crack, since it sounds like a problem I used to have a lot.
It sounds like the reason that your key presses aren't being recognized is that the focus is on one of the buttons. If you add keylisteners to the buttons, then you shouldn't have any problem.
In netbeans you can add keylisteners through the design screen really easily.
Here's a picture showing you how to add a keyPressed listener to a button in a jPanel.
private void jButton1KeyPressed(java.awt.event.KeyEvent evt) {
//Check which key is pressed
//do whatever you need to do with the keypressed information
}
It is nice to be able to write out the listeners yourself, but if you are just learning, then it is also nice to get as much help as possible.
This might not be the best solution, since you would have to add the listener for each of your buttons.
Does anyone know how to make a jbutton close a gui? I think it is like System.CLOSE(0); but that didnt work. it also could be exitActionPerformed(evt);, but that didn't work either. just the line of code will work.
EDIT: never mind guys. the answer was System.exit(0);. thanks for the help though!
Add your button:
JButton close = new JButton("Close");
Add an ActionListener:
close.addActionListner(new CloseListener());
Add a class for the Listener implementing the ActionListener interface and override its main function:
private class CloseListener implements ActionListener{
#Override
public void actionPerformed(ActionEvent e) {
//DO SOMETHING
System.exit(0);
}
}
This might be not the best way, but its a point to start. The class for example can be made public and not as a private class inside another one.
By using System.exit(0); you would close the entire process. Is that what you wanted or did you intend to close only the GUI window and allow the process to continue running?
The quickest, easiest and most robust way to simply close a JFrame or JPanel with the click of a JButton is to add an actionListener to the JButton which will execute the line of code below when the JButton is clicked:
this.dispose();
If you are using the NetBeans GUI designer, the easiest way to add this actionListener is to enter the GUI editor window and double click the JButton component. Doing this will automatically create an actionListener and actionEvent, which can be modified manually by you.
See JFrame.setDefaultCloseOperation(DISPOSE_ON_CLOSE)1. You might also use EXIT_ON_CLOSE, but it is better to explicitly clean up any running threads, then when the last GUI element becomes invisible, the EDT & JRE will end.
The 'button' to invoke this operation is already on a frame.
See this answer to How to best position Swing GUIs? for a demo. of the DISPOSE_ON_CLOSE functionality.The JRE will end after all 3 frames are closed by clicking the X button.
You may use Window#dispose() method to release all of the native screen resources, subcomponents, and all of its owned children.
The System.exit(0) will terminates the currently running Java Virtual Machine.
In Java 8, you can use Lambda expressions to make it simpler.
Close application
JButton btnClose = new JButton("Close");
btnClose.addActionListener(e -> System.exit(0));
Close window
JButton btnClose = new JButton("Close");
btnClose.addActionListener(e -> this.dispose());
Create a method and call it to close the JFrame, for example:
public void CloseJframe(){
super.dispose();
}
JButton close = new JButton("Close");
close.addActionListener(this);
public void actionPerformed(ActionEvent closing) {
// getSource() checks for the source of clicked Button , compares with the name of button in which here is close .
if(closing.getSource()==close)
System.exit(0);
// This exit Your GUI
}
/*Some Answers were asking for #override which is overriding the method the super class or the parent class and creating different objects and etc which makes the answer too long . Note : we just need to import java.awt.*; and java.swing.*; and Adding this command : class className implements actionListener{} */
private void button_Clicked_download(MouseEvent e) {
button_dl.setEnabled(false);
System.out.println("Button Clicked.");
}
When I click the button the button looks disabled. However the button still executes the code under the MouseEvent and I see "Button Clicked." in the debug console.
How can I make it so if the button is clicked it ignores the code and is indeed disabled?
However the button still executes the code under the MouseEvent and I see "Button Clicked." in the debug console.
This is exactly why you shouldn't use a MouseListener with a JButton but rather an ActionListener. The solution is of course obvious -- to get rid of the MouseListener and instead add an ActionListener to the JButton of interest.
you need to use an ActionListener instead of MouseClickListener.
your button is logically clicked even if it is disabled so click event will execute
There is actually a very simple way of enabling and disabling a button in java which uses a Mouse Listener.
class HoldListen extends MouseAdapter {
#Override
public void mousePressed(MouseEvent e) {
JButton bt = (JButton)e.getSource();
if (!bt.isEnabled()) {
return;
}
// Do code
}
}
I found your question while trying to create something similar and this is how I solved it.
All the MouseListener's methods return void so it works out quite nice. In my situation going back to an ActionListener would have required a lot of extra work while a MouseListener was perfect for the job. Press set a variable which Release undid and another thread used the variable in a ongoing simulation.