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Thread: Quick question regarding ActionListeners

  1. #1
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    Default Quick question regarding ActionListeners

    Hey, just have a quick question. I'm creating a GUI for a program which does different calculations based on what button you press and it's my first time using ActionListeners. I'm wondering, do I have to create a new class implementing ActionListener for every individual button or is there a different way of coding them. For example, below is the part of my code where I have my action listeners and it just seems a bit tedious to have to keep implementing that class, especially when some of the actions are very similar. Many thanks in advance for any help given.

            class BasicListener implements ActionListener { // Calculate basic pay
     
    		public void actionPerformed(ActionEvent e) {
    			String bPay = _basicHours.getText();
    			bAmount = Double.parseDouble(bPay) * BASIC_PAY;
    			_basicTotal.setText(""+bAmount);
     
    		}
    	}
     
    	class HolsListener implements ActionListener { // Calculate holiday pay
    		public void actionPerformed(ActionEvent e) {
    			String hPay = _holsHours.getText();
    			hAmount = Double.parseDouble(hPay) * HOLS_PAY;
    			_holsTotal.setText(""+hAmount);
     
    		}
     
    	}
     
    	class TotalListener implements ActionListener { // Calculate final earnings
     
    		public void actionPerformed(ActionEvent e) {
    			finalAmount = bAmount+hAmount;
    			_finalAmount.setText("" + finalAmount);
    		}
    	}


  2. #2
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    Default Re: Quick question regarding ActionListeners

    You could use one instance of a single ActionListener, added to each JButton, that checks the source in the actionEvent() method and does the appropriate thing. Something like:

    class MyActionListener implements ActionListener(){
       public void actionPerformed(ActionEvent e){
          if(e.getSource() == button1){
          System.out.println("clicked 1");
          }
          else if(e.getSource() == button2){
             System.out.println("clicked 2");
          }
       }
    });
    //...
    ActionListener al = new MyActionListener();
    button1.addActionListener(al);
    button2.addActionListener(al);

    Or you could look into using an anonymous inner class. Something like:

    button1.addActionListener(new ActionListener(){
       public void actionPerformed(ActionEvent e){
          System.out.println("clicked 1");
       }
    });
     
    button2.addActionListener(new ActionListener(){
       public void actionPerformed(ActionEvent e){
          System.out.println("clicked 2");
       }
    });
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  4. #3
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    Default Re: Quick question regarding ActionListeners

    Ah they seem much handier. I knew there had to be a better way I just couldn't work out how. Thanks a lot (Apologies for making a thread out of this)

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