"alias" einer Klassen-Instanz als Verweis auf "echte" Instanz

[HaWe]

ich hatte es nur nachträglich geändert, zur Verdeutlichung, aber das menu02 ist auch da.

Der vollständige Code ist ein wenig erweitert gegenüber dem gekürzten Beispiel - hoffe, es ist nicht zuviel

// I2C
#include <Wire.h>         // Incl I2C comm, but needed for not getting compile error
#define ESPSDA D2         // defaults
#define ESPSCL D1         // 

// TFT
//#include <Adafruit_SSD1306.h>
#include <ESP_SSD1306.h>    // Modification of Adafruit_SSD1306 for ESP8266 compatibility
#include <Adafruit_GFX.h>   // Needs a little change in original Adafruit library (See README.txt file)
#include <Fonts/FreeSans12pt7b.h>            // 
#include <Fonts/FreeSansBold12pt7b.h>        // 
#include <Fonts/FreeSans9pt7b.h>             //
#include <Fonts/FreeMono12pt7b.h>            //   
#include <Fonts/FreeMono9pt7b.h>    
// Pin definitions

//----------------------------------------------------------------------------
// display driver
//----------------------------------------------------------------------------
#define OLED_RESET 10  // GPIO10=D12 Pin RESET signal (virtual)

//Adafruit_SSD1306 display(OLED_RESET);
//Adafruit_SSD1306 display(128, 64, &Wire, OLED_RESET);
ESP_SSD1306 display(OLED_RESET);  


//----------------------------------------------------------------------------
// ButtonClass buttons
//----------------------------------------------------------------------------

#include <ButtonClass.h>
// 3 buttons for menu control
tButton btn0;
tButton btn1;
tButton btnfx;


 
//----------------------------------------------------------------------------
// OLED menu
//----------------------------------------------------------------------------
 
class tMenu {  
  protected:    
     int16_t    MENULEN, LINELEN, VISLNUM, FONTHI; 
     char       buf[20];     
     int8_t     firstvln, lastvln, displn;   
  
  public:      
     int16_t ID, pre_ID;
     int8_t  act, pre_act;
     char    **list; 
     int     test;    
     
     tMenu (int16_t menulen, int16_t linelen, int16_t id) // constructor
     {
        firstvln=0; lastvln=0; displn=0;     
        pre_ID=0;
        act=0;
        pre_act=0;
        MENULEN = menulen;  // number of available menu options        
        LINELEN = linelen;  // line length of menu options 
        ID = id;       
               
        list = new char*[MENULEN];
        for(int i = 0; i < MENULEN; i++)
        {
          list[i] = new char[LINELEN+1];
        }        
     }      
     
     void init(int16_t vislnum=5, byte fonthi=13 ) {  // ()=defaults=(5,13)
        for(int i=0; i<MENULEN; i++) {
           sprintf(buf,"%d .......|", i);
           strncpy(list[i], buf, LINELEN);
           VISLNUM = vislnum;  // number of visible menu options
           FONTHI = fonthi;
        }
     }

     void mdisplay() {          
        if(act>VISLNUM-1) firstvln=_min(act-1, MENULEN-VISLNUM);
        else firstvln=0;       
        lastvln=firstvln+VISLNUM-1; 
        display.clearDisplay();
        for(byte i=firstvln; i<=lastvln; i++) {                   
            displn=(FONTHI-3) + (i-firstvln)*FONTHI;
            if(i==act) {                
              display.setCursor(0, displn);  display.print('>'); 
              Serial.print('>');           
            }
            else Serial.print(' ');
            Serial.println(list[i]);
            display.setCursor(11, displn);  display.print(list[i]);
        }       
        display.display();
        Serial.println();
     }

     int32_t checkbtn(int8_t btop, int8_t bbtm, int8_t bfunc) {
        if(btop==1){ // dec
           if(act>0) act--;
           //Serial.print ("^"); Serial.println(act);
           mdisplay();
           return 11 ;
        }
        if(btop==3){  // min
           act=0;
           //Serial.print ("^"); Serial.println(act);
           mdisplay();
           return 13 ;
        }
        if(bbtm==1){  // inc
           if(act<MENULEN-1) act++;
           //Serial.print ("v"); Serial.println(act);
           mdisplay();
           return 21;
        }
        if(bbtm==3){  // max
           act=MENULEN-1;
           //Serial.print ("v"); Serial.println(act);
           mdisplay();
           return 23;
        }
        if(bfunc==1){           
           sprintf(buf,"Menu %d-%d ToDo=%d", ID,act,bfunc);
           Serial.println(buf);
           return 1;
        }
        if(bfunc==2){           
           sprintf(buf,"Menu %d-%d ToDo=%d", ID,act,bfunc);
           Serial.println(buf);
        }
        if(bfunc==3){           
           sprintf(buf,"Menu %d-%d ToDo=%d", ID,act,bfunc);
           Serial.println(buf);
           return 3;
        }
        return 0;         
     }
  
     ~tMenu()  { // destructor    
        // Dynamically delete the array  
        delete[] list ;
     }
};
 

tMenu menu0(10,20, 0); // numEntries, lineLength, menuID;
tMenu menu02(10,20, 2); 


tMenu & actMenu = menu0;
tMenu & preMenu = menu0;





//----------------------------------------------------------------------------
// OLED dashboard
//----------------------------------------------------------------------------

void dashboard(byte mode) {     

  display.clearDisplay();
  display.setFont();

  if (mode == 0) {
    display.setFont();  // h=8.0 pt
    display.setCursor( 0,  0);  display.print(" 0 Hello World 1");    
  }
  display.display();
  display.setFont();
}
  
                     

void setup(void)
{
	// Start Serial
  //pinMode(D3, OUTPUT);       // + LED_BUILTIN


  btn0.init(D6, INPUT_PULLUP, 50);
  btn1.init(D3, INPUT_PULLUP, 50);
  btnfx.init(D4, INPUT_PULLUP, 50);
  
 
  //pinMode(D7, OUTPUT);
  //pinMode(D8, OUTPUT);
  
	Serial.begin(115200);
  delay(2000); // wait for Serial()
  Serial.println("Serial started");

  
  // Start Wire (SDA, SCL)
  //Wire.begin(ESPSDA,ESPSCL);  // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  Wire.begin();

  // SSD1306 Init  
  display.begin(SSD1306_SWITCHCAPVCC);  // Switch OLED
  //display.begin(SSD1306_SWITCHCAPVCC, 0x3D, true, false);
  display.setRotation(2);  
  display.clearDisplay();  // Clear the buffer.

  // text display tests
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0,0);
  display.println("Hello, world!");  
  display.display();

  //--------------------------------------
  // test +  debug

  Serial.println();
  for(byte i=0; i<10; i++) {
     Serial.print("-");
     Serial.println(menu0.list[i]);
  }
  menu0.init(); // optional numVisibleLines, fontHeight; defaults = (5,13)
  display.clearDisplay(); 
  display.display();

  display.setFont(&FreeMono9pt7b); // h=13.10pt
  menu0.mdisplay();
}


void loop() {
    int32_t result;
    
    result = menu0.checkbtn(btn0.click(), btn1.click(), btnfx.click() ); 

    &actMenu = menu02; // test
    
    
}