CODEWITHSUNDEEP
javauser-interfaceactionlistener
John
John

Reputation: 63

how to use ActionListeners in java properly

Through some searching, I made about ActionListeners and GUI. I think I have come to a conclusion that all the changes you do that affect the GUI, in the ActionListener, actually happen when ActionListener comes to it's end I am currently making a memory game. In the action listener of a card button I first flip the image (that changes it's icon) and the I check if a have a match and in the case I don't have one I close the card(change icon).

Since those two happen in the same actionListener as a result if I dont have a match I only see the first card I pick and he second seems to no react to flip. Sorry if it's confusing how I explain it. I think that the problem is the actionListener but maybe I am wrong. What would you suggest?

c.addActionListener(new ActionListener(){
     @Override
        public void actionPerformed(ActionEvent ae){

           selectedCard = c;

                String imgName = "Images/"+c.getId()+".jpg";

URL imageURL = this.getClass().getResource(imgName);
 if (imageURL != null) {   

      ImageIcon icons = new ImageIcon(imageURL);

       c.setIcon(icons);

}
             c.setEnabled(false);
             c.setDisabledIcon(c.getIcon());
                pl.singlePlay(c);

                   if(pl.getMatch()==false){

                       for (Cards cd : cards){

                           if(cd.getMatched()==false){   
                               cd.setEnabled(true);
                              cd.setIcon(icon);

                       }
                    }

                    }

});

Upvotes: 0

Views: 61

Answers (1)

camickr
camickr

Reputation: 324108

I have come to a conclusion that all the changes you do that affect the GUI, in the ActionListener, actually happen when ActionListener comes to it's end

Yes, all code invoked from any listener executes on the Event Dispatch Thread (EDT). This thread is responsible for updating the GUI and so the GUI can't be updated until the code has finished executing. Read the section from the Swing tutorial on Concurrency for more information.

Since those two happen in the same actionListener

If you want to schedule animation, that is show one Icon and then seconds later show another Icon, then you can use a Swing Timer. The Timer allows you to schedule another event. The tutorial link from above also has a section on How to Use Swing Timers to get you started.

Upvotes: 3

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