i want to call main class constructor from inner class or smt...

[Juhan Voolaid]

Hi
I have a simple problem, but i don't know how to solve it.
The situation is:
Program has main class Hero and the constructor Hero() where are several panels. One panel has buttons. Each panel is defined in inner class.
Now i want to do so that, if i press button from lets say buttonPanel i want to see something happening in other panel - lets say actionPanel. Problem is that when i press button - actionPanel must be refreshed - to do that i must call actionPanel constructor i think.
Hohh ... this is creazy to explain ... i write a little code below ... try to make sense of that and correct me

  
public class hero extends JFrame{
buttonPanel B;
actionPanel A;


public static void main(String[] args){
hero h = new hero();
}
        public hero(){
JFrame f=new JFrame();
                f.setSize(640,480);
f.setDefaultCloseOperation(EXIT_ON_CLOSE);
       //--- set somekind of layout and now i add the 2 panels ----
                A=new actionPanel();//i'm not sure if this parts work like 
//this with what i want to do
                B=new buttonPanel();
                add(A);
                add(B);
        }//end of hero constructor
class buttonPanel extends JPanel implements ActionListener{
JButton start, options;

public buttonPanel(){
super();
//---------again some layout and then add 2 buttons -------
                start=new JButton("start");
                options=new JButton("options");
                add(start);
                add(options);
                }//end of constructor
public void actionPerformed(ActionEvent e){

String action=e.getActionCommand();
if (action.equals("start")){
//PROBLEM:
//do something to desplay JLabel("start") on my actionPanel
//i would call actionPanel constructor with action string
actionPanel(action);
//but it is wrong
//correct code here pleas:
}
}//end of buttonPanel
class actionPanel extends JPanel{){
  JPanel info;
  actionPanel(String action){
super();
        info=new JLabel(action);
        add(info);
 }
 actionPanel(String action){
super();
 }
}//end of inner actionPanel class
}//end of hero class

I hope u get the idea and know to give me some advice or something....

[Craig Wood]

One way to do this is to give (pass) an ActionPanel reference (namely, actionPanel) to the ButtonPanel class so ButtonPanel can call methods inside ActionPanel. So we pass the reference to the constructor when we instantiate (create an instance of) ButtonPanel. Now the buttons in ButtonPanel can use the reference to call methods inside ActionPanel.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class Hero extends JFrame {
    ButtonPanel buttonPanel;
    ActionPanel actionPanel;
 
    public static void main(String[] args) {
        new Hero();
    }
 
    public Hero() {
        actionPanel = new ActionPanel();
        buttonPanel = new ButtonPanel(actionPanel);
        getContentPane().add(buttonPanel, "North");
        getContentPane().add(actionPanel, "Center");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(400,300);
        setLocation(200,200);
        setVisible(true);
    }
 
    private class ButtonPanel extends JPanel implements ActionListener {
        ActionPanel actionPanel;
        JButton startButton, optionsButton;
        int startCount = 0;
 
        public ButtonPanel(ActionPanel actionPanel) {
            this.actionPanel = actionPanel;
            startButton = new JButton("start");
            optionsButton = new JButton("next option");
            startButton.addActionListener(this);
            optionsButton.addActionListener(this);
            add(startButton);
            add(optionsButton);
        }
 
        public void actionPerformed(ActionEvent e) {
            JButton button = (JButton)e.getSource();
            if(button == startButton)
                actionPanel.showMessage("starting " + ++startCount);
 
            if(button == optionsButton)
                actionPanel.displayOptions();
        }
    }
 
    private class ActionPanel extends JPanel {
        JLabel messageLabel, optionsLabel;
        String[] options = {
          "option 1", "option 2", "option 3", "option 4"
        };
        int optionIndex = 0;
 
        public ActionPanel() {
            messageLabel = new JLabel(" ", JLabel.CENTER);
            messageLabel.setPreferredSize(new Dimension(175, 25));
            optionsLabel = new JLabel(" ", JLabel.CENTER);
            optionsLabel.setPreferredSize(new Dimension(175, 25));
            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.weighty = 1.0;
            gbc.gridwidth = gbc.REMAINDER;
            add(messageLabel, gbc);
            add(optionsLabel, gbc);
        }
 
        public void showMessage(String message) {
            messageLabel.setText(message);
        }
 
        public void displayOptions() {
            String option = options[optionIndex++ % options.length];
            optionsLabel.setText(option);
        }
    }
}

[Dirk Schreckmann]

Moving this to the Swing / JFC / AWT forum, where folks just love to get all messy with this GUI stuff...

[Juhan Voolaid]

Thank you, thank you very much for such a good answer to such a messy question Craig Wood!!!
I feel i jsut gained a level in Java because of u

[Juhan Voolaid]

One other thing ....

  
public ButtonPanel(ActionPanel actionPanel) {            
  [B]this.actionPanel = actionPanel;[/B]            
  startButton = new JButton("start");            
  optionsButton = new JButton("next option");           
  startButton.addActionListener(this);             
  optionsButton.addActionListener(this);            
  add(startButton);           
  add(optionsButton);        
}

what does this line
this.actionPanel = actionPanel;
do in this example?
[ February 15, 2004: Message edited by: Juhan Voolaid ]

[Nathan Pruett]

It assigns the value of local variable named "actionPanel" (that was passed in as a parameter to the constructor), to the member variable named "actionPanel" that is defined asa part of the ButtonPanel class. The "this" keyword lets you access object-level or class-level attributes and methods of the current object.

[Juhan Voolaid]

OK ... ive got new problems that i can't find answers. It is with this same example so i continue with this topic.
OK after i changed my program a bit it still doesen't work. When i push a button - this action panel will be blank. But to the console in backround appers lot of stuff ... something about:
java.lang.nullpointer exception
lot of stuff about action performed things
and what i think is the most important - EventDispatchThread
In this example i didn't use any threads (didn't think it's neccesary) - so i have no idea what should i do next.
I think it enaugh if i give u code about 2 classes this buttonPanel and actionPanel - but in my example they are buttonPanel=b and infopanel=i
hope u understand and can help me.
Here is the code:

  
class buttonPanel extends JPanel implements ActionListener{
JPanel center;
JLabel north;
JButton stats, health, inv, spells, notes, score;
infoPanel i;

buttonPanel(infoPanel i){
this.i=i;
setBorder(new EtchedBorder(EtchedBorder.LOWERED));
BorderLayout BL = new BorderLayout();
setLayout(BL);

north=new JLabel("Menu:", SwingConstants.CENTER);
center=new JPanel();
add(north, BL.NORTH);

GridBagLayout GB=new GridBagLayout();
GridBagConstraints c=new GridBagConstraints();

stats=new JButton("Stats");
stats.addActionListener(this);
health=new JButton("Health");
health.addActionListener(this);
inv=new JButton("Inv.");
inv.addActionListener(this);
spells=new JButton("Spells");
spells.addActionListener(this);
notes=new JButton("Notes");
notes.addActionListener(this);
score=new JButton("Score");
score.addActionListener(this);

center.setLayout(GB);
c.fill=GridBagConstraints.BOTH;
c.gridx=0;
c.gridy=0;
GB.setConstraints(stats, c);
center.add(stats);

c.gridx=0;
c.gridy=1;
GB.setConstraints(health, c);
center.add(health);

c.gridx=1;
c.gridy=0;
GB.setConstraints(inv, c);
center.add(inv);

c.gridx=1;
c.gridy=1;
GB.setConstraints(spells, c);
center.add(spells);

c.gridx=0;
c.gridy=2;
GB.setConstraints(notes, c);
center.add(notes);

c.gridx=1;
c.gridy=2;
GB.setConstraints(score, c);
center.add(score);

center.setBorder(new EtchedBorder(EtchedBorder.LOWERED));
add(center, BL.CENTER);

}


public void actionPerformed(ActionEvent e){

JButton button = (JButton)e.getSource();

if(button == stats)  
i.showMessage("stats");

if(button == health)                
i.displayOptions(); 
 
}

}


class infoPanel extends JPanel{
JLabel messageLabel, optionsLabel;

public infoPanel(){
messageLabel = new JLabel();
optionsLabel = new JLabel();
add(messageLabel);
add(optionsLabel);


}

public void showMessage(String message) {
messageLabel.setText(message);
}

public void displayOptions() {            

optionsLabel.setText("option :) ");
}

}