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Thread: actionPerformed

  1. #1
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    Default actionPerformed

    Hi,

    I've made a button listen for actions.

    button.addActionListener(this);

    so, let's say the button is clicked twice, will actionPerformed() be invoked twice too ?


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    Default Re: actionPerformed

    What happened when you tried it?

    db

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    Default Re: actionPerformed

    Quote Originally Posted by Darryl.Burke View Post
    What happened when you tried it?

    db
    It gets invoked only once.. if it's a limitation, how can I work around it?

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    Default Re: actionPerformed

    To get better help sooner, post a SSCCE that clearly demonstrates your problem.

    db

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    Thumbs up Re: actionPerformed

    problem solved... thanks.
    Last edited by Kumarrrr; November 23rd, 2010 at 09:41 PM.

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    Default Re: actionPerformed

    public void actionPerformed(ActionEvent e)
    {
    		int i = 1;
    		button.setText("I've been clicked "+ i + " number of times");
    		i++;
     
    // so, everytime the button is clicked, I want the button text to change.
     
    }

    To put it bluntly, you are wrong. The button does work each time you press it, but the value of i never changes. The reason is that each time you press the button, i get reinitialized to 1. This is also an issue of something called scope. Scope determines what parts of your code can see what other parts of your code. When you press the button once, i is set to 1, then the method increments it to 2. When you press the button the second time, the method cannot see the i from the previous method call so creates a new variable named i, sets it to 1, sets the button text, and increments i to 2. It will continue to do that each time you press the button.

    The fix to this is declaring your counter variable outside of the actionPerformed method. This should do it:
    int i = 1;
    public void actionPerformed(ActionEvent e)
    {
     
    		button.setText("I've been clicked "+ i + " number of times");
    		i++;
     
    // so, everytime the button is clicked, I want the button text to change.
     
    }
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  7. The Following User Says Thank You to aussiemcgr For This Useful Post:

    Kumarrrr (November 23rd, 2010)