Using Different Java Code in a Project (How to reach variables)

Question

I wrote a simple drawing program, and for to create a menu, I used this source, http://download.oracle.com/javase/tutorial/displayCode.html?code=http://download.oracle.com/javase/tutorial/uiswing/examples/components/MenuLookDemoProject/src/components/MenuLookDemo.java

Therefore in my program to show the menus, I only added these lines:

    MenuDemo demo = new MenuDemo();
    frame.setJMenuBar(demo.createMenuBar());

When I started the program, menu successfully works, but on the other hand, for example, when I click sth on menu, in method "actionPerformed" I want to change my program's boolean variable. But "actionPerformed" is exist in "MenuLookDemo.java", therefore I cannot reach the variables.

Can you suggest a solution please ?

Thanks

You should really start reading about Object-Oriented design. This is a OO-101-level question. — Romain
– Romain, Commented Oct 3, 2011 at 14:41
Is it not OK to ask OO-101 level questions here? I thought it was perfectly OK to ask this kind of stuff. — Jim Kiley
– Jim Kiley, Commented Oct 3, 2011 at 14:49

Pikaurd · Accepted Answer · 2011-10-03 14:45:22Z

1

Maybe you can rewrite the class MenuDemo and pass your Object to MenuDemo to access your variable.

class MenuDemo{
  YourType obj;
  MenuDemo(YourType obj){
    this.obj = obj;
  }
  // Now you can access elements of obj
}

answered Oct 3, 2011 at 14:45

Pikaurd

1,1341 gold badge8 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Jim Kiley Over a year ago

Pikaurd is right -- MenuDemo needs some way to send information to your program (really -- your object, represented in his sample as 'obj').

CanCeylan Over a year ago

I tried this one, but the main problem is, I want some variables to be effected when "actionPerformed" event flagged. I added arguments to the MenuDemo, but I cant send this object to "actionPerformed" method, therefore I cant reach that variable

Pikaurd Over a year ago

Where is your actionPerformed? Can your paste your project structure here? I thought actionPerformed in MemoDemo, so the menu element could handle actions its received.

Jim Kiley · Accepted Answer · 2011-10-04 02:29:04Z

0

Building off of what Pikaurd has above, do this:

public class MyType {
  int x;
  public void doTheNeedful() {
    x = 5;
  }
}

Then make sure MenuDemo contains a field obj of class MyType. Inside actionPerformed(), call obj.doTheNeedful().

I'm deliberately not just giving you the code on this; the sentence above should be enough for you to figure it out.

answered Oct 4, 2011 at 2:29

Jim Kiley

3,6523 gold badges29 silver badges43 bronze badges

Collectives™ on Stack Overflow

Using Different Java Code in a Project (How to reach variables)

2 Answers 2

3 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related