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Thread: add action listener problem

  1. #1
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    Default add action listener problem

    i have getting errors when i try to compile this code relating to ACTIONLISTENER . i use JDK1.3


    import java.awt.*;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
     
    class temp extends Frame
    {
    Button b1,b2;
    Label l1,l2;
    TextField t1,t2;
    public temp (String t)
    {
    super(t);
    b1=new Button("CONVERT");
    b2=new Button("CANCEL");
    l2=new Label("TEMPRETURE IN C");
    l1=new Label("TEMPRETURE IN F");
    t1=new TextField("20");
    t2=new TextField("20");
    setLayout (new FlowLayout());
    add(l1);
    add(t1);
    add(l2);
    add(t2);
    add(b1);
    add(b2);
    t2.setEditable(false);
    setSize(500,500);
    setVisible (true);
    b1.addActionListener(this);
    b2.addActionListener(this);
    }
    public void actionPerformed(ActionEvent e)
    {
    if(e.getSource()==b1)
    {
    float a=Float.parseFloat(t1.getText());
    float b;
    b=(9/5*(a+32));
    t2.setEditable(true);
    t2.setText (String.valueOf(b));
    t2.setEditable(false);
    show();
    }
    if(e.getSource()==b2)
    {
    System.exit (0);
    } } }


  2. #2
    Administrator copeg's Avatar
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    Default Re: add action listener problem

    i have getting errors
    What errors? Post them in their entirety (and read the link in my signature entitled 'getting help' if you want to make the most of these forums)

  3. #3
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    Default Re: add action listener problem

    these are the errors on compilation . i use jdk1.3
    Attached Images Attached Images

  4. #4
    Java kindergarten chronoz13's Avatar
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    Default Re: add action listener problem

    b1.addActionListener(this);
    b2.addActionListener(this);

    these 2 addActionListeners(this) or the reserved word 'this' refer to your class's instance(a temp instance), not to an instance of an ActionListener interface or a class that implements an ActionListener interface

    better start from here
    How to Write an Action Listener (The Java™ Tutorials > Creating a GUI With JFC/Swing > Writing Event Listeners)
    Last edited by chronoz13; January 29th, 2012 at 05:26 AM.

  5. #5
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    Default Re: add action listener problem

    Quote Originally Posted by chronoz13 View Post
    b1.addActionListener(this);
    b2.addActionListener(this);

    these 2 addActionListeners(this) or the reserved word 'this' refer to your class's instance(a temp instance), not to an instance of an ActionListener interface or a class that implements an ActionListener interface

    better start from here
    How to Write an Action Listener (The Java™ Tutorials > Creating a GUI With JFC/Swing > Writing Event Listeners)
    great thanks .

  6. #6
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    Default Re: add action listener problem

    you should first implement ActionListener to use actionEvent.

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