How to check the state of an JCheckBox?

Question

I'd like to mute my music player player using player.mute() when the JCheckBox mutemusic_box is checked. If its unchecked and the player is muted, the command player.mute() should execute. How to get this working? My code currently does not work (may because of the ActionEvent).

The check if it's checked or not is in actionPerformed.

private JCheckBox pwremember_box, mutemusic_checkbox;

//GUI setup

public void actionPerformed(ActionEvent ae) {

    if (mutemusic_checkbox.isSelected()) {
        System.out.println("Muted!");
        player.mute();
    }
    else {
      System.out.println("Unmuted!");
      player.mute();
    } 
}

I am new to java. Feel free to comment so I can improve my asking skills. May the issue is in the ActionEvent. — realKSMC, Jul 30 '17 at 17:05
Possible duplicate of [How to check that a JCheckBox is checked?](https://stackoverflow.com/questions/3599908/how-to-check-that-a-jcheckbox-is-checked) — Jonny Henly, Jul 30 '17 at 17:12
you must `addActionListener` (conatining the `actionPerformed`) to your checkbox, else the GUI would not *know* that the `actionPerformed` should be called. — user85421, Jul 30 '17 at 17:29
Could you post this as an answer? I do not know how to get this done. — realKSMC, Jul 30 '17 at 17:31
see Oracle's tutorial [How to Use Buttons, Check Boxes, and Radio Buttons](https://docs.oracle.com/javase/tutorial/uiswing/components/button.html), these are pretty good to learn the basics and how classes are intended to be used. And here at the right there are at least to links that could help (under **Linked**) ==> — user85421, Jul 30 '17 at 17:40
or just look at [davidxxx' answer](https://stackoverflow.com/a/45402509/85421) below, he just added it - - - but I still recommend the tutorials! — user85421, Jul 30 '17 at 17:45

davidxxx · Accepted Answer · 2017-07-30T17:42:09.157

4

First this check is not required :

if (ae.getSource().equals(mutemusic_box)) {

The ActionListener should be associated to the JCheckBox button.
So, there is not any ambiguity.

Then in order to know if the checkbox is checked, use simply the isSelected() method that is designed for.

Besides mute() is not a good named method to toggle the sound of the Player.
toggleSound() could make more sense.

And as explained in my comment, you have to attach first the listener to the JCheckBox.

Here is a sample code :

checkBoxMute.addActionListener(
   new ActionListener(){
        public void actionPerformed(ActionEvent ae) {   
          if (checkBoxMute.isSelected()) {
              System.out.println("Muted!");
              player.toggleSound();
          }
          else {
              System.out.println("Unmuted!");
              player.toggleSound();
          } 
       }
   });

And here the same thing with a lambda instead of creating an anonymous class of ActionListener :

checkBoxMute.addActionListener(
    ae -> {
        if (checkBoxMute.isSelected()) {
          System.out.println("Muted!");
          player.toggleSound();
        } else {
          System.out.println("Unmuted!");
          player.toggleSound();
        }
    });
}

edited Jul 30 '17 at 17:42

answered Jul 30 '17 at 17:09

davidxxx

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Thx for ur idea to rename it. I tried it but nothing is printed in console, also the sound does not mute. Any idea? – realKSMC Jul 30 '17 at 17:14
You are welcome. Are you sure to have attached the ActionListener to the checkbox that you select/unselect ? – davidxxx Jul 30 '17 at 17:16
Yes. I will update my code and show how `mutemusic_checkbox` looks. – realKSMC Jul 30 '17 at 17:18
Please have a look at my updated code :) Now its correct :P – realKSMC Jul 30 '17 at 17:22
1

It was not attached to. I updated. It is very simple. – davidxxx Jul 30 '17 at 17:42
1

@realKSMC You cannot edit a answer to add your own answer in. If you think that adding your code makes sense, add an answer :) – davidxxx Jul 30 '17 at 19:14

xenteros · Answer 2 · 2017-07-30T17:07:42.187

1

You can use isSelected method.

boolean isChecked = mutemusic_box.isSelected();

As a personal advice, rename mutemusic_box to muteMusicCheckBox or similar.

edited Jul 30 '17 at 17:07

answered Jul 30 '17 at 17:06

xenteros

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Where exactly to use it? :) Thx for the quick respond! – realKSMC Jul 30 '17 at 17:06
once you have a reference to a `JCheckBox` you can call it on this object. – xenteros Jul 30 '17 at 17:07
Can you give me an example? I am new to java ;) – realKSMC Jul 30 '17 at 17:07
@realKSMC here u are – xenteros Jul 30 '17 at 17:08
Noticed your updated answer :) I will change the name, thx for that. I'll try something out and give an respond . – realKSMC Jul 30 '17 at 17:10
@realKSMC you can mark this answer as solution by clicking on a gray tick below the answer score – xenteros Jul 30 '17 at 17:22

score -1 · Answer 3 · answered Jul 30 '17 at 17:08

-1

You can try

mutemusic_box.isSelected();

answered Jul 30 '17 at 17:08

Akash

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2

While this code snippet may solve the question, [including an explanation](http://meta.stackexchange.com/questions/114762/explaining-entirely-code-based-answers) really helps to improve the quality of your post. Remember that you are answering the question for readers in the future, and those people might not know the reasons for your code suggestion. – DimaSan Jul 30 '17 at 22:51

How to check the state of an JCheckBox?

3 Answers3