ofxGui, Panel in each class example

main.cpp

#include "ofMain.h"
#include "ofApp.h"

//========================================================================
int main( ){

	ofSetupOpenGL(1024,768, OF_WINDOW);			// <-------- setup the GL context

	// this kicks off the running of my app
	// can be OF_WINDOW or OF_FULLSCREEN
	// pass in width and height too:
	ofRunApp( new ofApp());

}

MyClass.h

//
//  MyClass.h
//

#pragma once

#include "ofxGui.h"

class MyClass{

public:

    MyClass(int i){
        string name = "settings" + ofToString(i);
        gui.setup(name, name+".xml", (i-1)*220, 0);
        gui.add(grp);
        gui.loadFromFile(name+".xml");
    }
    
    void draw(){
        gui.draw();
    }
    
    ofParameter<int> myInt{"MyInt", 0, 0, 100};
    ofParameterGroup grp{"My Class", myInt};
    ofxPanel gui;
    
};

ofApp.cpp

#include "ofApp.h"

//--------------------------------------------------------------
void ofApp::setup(){
    
    myClasses.reserve(10);
    
    for(int i=0; i<2; i++){
        myClasses.emplace_back(i+1);
    }
}

//--------------------------------------------------------------
void ofApp::update(){

}

//--------------------------------------------------------------
void ofApp::draw(){

    for(auto & c : myClasses){
        c.draw();
    }
}

ofApp.h

#pragma once

#include "ofMain.h"
#include "MyClass.h"

class ofApp : public ofBaseApp{
public:
    void setup();
    void update();
    void draw();
    
    vector<MyClass> myClasses;
};