Basic GUI question (showing info from another class)

Hi ive been intensly studying java now for a few weeks and ive moved steadily onto GUI's and my question to the forum is, how do i show information about an objects variable in a label on a GUI form?

ill write some quick code here, please excuse any errors, i hope this will clarify my question


ok so ive created a main class called main
and ive created another class called person

in the main class
=================================

person john = new person(); //created a new object called person

john.setHeight(175);

===================================

==

the person class
======================================

public void person{

int height = -1;

void setHeight(int heightPassed){

height = heightPassed;

}
}

================================


ok so from above you can see i set the object viarable john.height to 175.
Now assuming a created a simple JFrame (GUI) form, how would i then show john.height in a label?

reason why i ask is because the GUI doesnt reconise the object john so whats the way round this?

thank you

Having GUI's work with other classes is little different from having non-GUI classes work with other classes. Let's see your attempt and then perhaps we can better help you with solving your problem.

Make a method called getHeight() in the person class. Reference person in the JFrame and then do something like:

Code:

---

JLabel label = new JLabel(john.getHeight());

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Several ways of achieving this. Assuming your GUI class extends JFrame, you could make a public method in that class that takes height. If so, you can do this in the main:

Code:

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public static void main (String[] args) {
    person john = new person(); //created a new object called person
    john.setHeight(175);
   
    CustomFrame frame = new CustomFrame(); //Your JFrame class is called
                                                              //CustomFrame
    frame.setHeight(john.getHeight()); //Assuming your frame class has this method
    frame.display(); //This method probably makes the frame visible, display it in the
                          //center, etc.

---

Quote:

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Originally Posted by Fubarable

Having GUI's work with other classes is little different from having non-GUI classes work with other classes. Let's see your attempt and then perhaps we can better help you with solving your problem.

---

ok im thinking that i could created a method inside the GUI class and then pass the peter obect to that method.
and then in the method basicalled make a JLabel = peter.height?
please excuse the pseudo code.

Quote:

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Originally Posted by Lil_Aziz1

Make a method called getHeight() in the person class. Reference person in the JFrame and then do something like:

Code:

---

JLabel label = new JLabel(john.getHeight());

---

---

Hey i tried this code and it didnt reconise the object, then i re-read what you wrote and you've mentioned ive got the "reference" the class person. How do i reference the class?

Code:

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person john = new person();

---

oh i see what you did, you created the object person in the GUI class.

In my example i created the object in the main class and wanted information from that object to show in the GUI class.

the reason why i want to know this is because in the future i may want to create a couple of GUI forms and i want them both to show information from one object which is held in a different class.

would one way going about it be to create an array list in the GUI class to hold objects, (create a method in the GUI class to get the object from the main class and put it in the arrayList which is in the GUI class) and then bingo, i can now play around with the object from the GUI class by refering to it from its position in the arraylist.

any thoughts?

WTFIT

Code:

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JLabe label=new JLabel();
...
label.setText("blabla");

---

easy

Then pass the non-GUI information in the main class to the GUI class via a parameter in a setter method or a constructor.

Quote:

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Originally Posted by Fubarable

Then pass the non-GUI information in the main class to the GUI class via a parameter in a setter method or a constructor.

---

oh i see, so it would be something like

public class Main {

public static void main(String[] args) {

someCLass object = someClass();
GUI form = new GUI(object);

}
}





public class GUI extends JFrame{

public GUI(someClass objectPassed){

objectPassed.dosomething;

}

}


so in the brief example above, the method "dosomething" should work?

Quote:

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Originally Posted by alacn

oh i see, so it would be something like
so in the brief example above, the method "dosomething" should work?

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The quickest way to find out: try it and see! :)