Menu de contexto

#include <LiquidCrystal.h>

// select the pins used on the LCD panel
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

// define some values used by the panel and buttons
int lcd_key     = 0;
int adc_key_in  = 0;
#define btnRIGHT  0
#define btnUP     1
#define btnDOWN   2
#define btnLEFT   3
#define btnSELECT 4
#define btnNONE   5

class Noh
{
public:
    char name[16]; // favor não usar o último caractere
    void* data; // o ponteiro do tipo void pode ser usado pra qualquer propósito
    Noh* next;
    Noh* previous;
    bool leads_to_another_menu;
    Noh();
    Noh(char* new_name){
        for (int i = 0; i < 16; ++i)
        {
            name[i] = new_name[i];
        }
    };
    ~Noh(){
        delete name;
        delete data;
    };

};

int read_LCD_buttons()
{
    adc_key_in = analogRead(0);      // read the value from the sensor
    // my buttons when read are centered at these valies: 0, 144, 329, 504, 741
    // we add approx 50 to those values and check to see if we are close
    if (adc_key_in > 1000) return btnNONE; // We make this the 1st option for speed reasons since it will be the most likely result
    // For V1.1 us this threshold
    if (adc_key_in < 50)   return btnRIGHT;
    if (adc_key_in < 250)  return btnUP;
    if (adc_key_in < 450)  return btnDOWN;
    if (adc_key_in < 650)  return btnLEFT;
    if (adc_key_in < 850)  return btnSELECT;
    // For V1.0 comment the other threshold and use the one below:
/*
    if (adc_key_in < 50)   return btnRIGHT;
    if (adc_key_in < 195)  return btnUP;
    if (adc_key_in < 380)  return btnDOWN;
    if (adc_key_in < 555)  return btnLEFT;
     if (adc_key_in < 790)  return btnSELECT;
*/
    return btnNONE;  // when all others fail, return this...
}

void print_menu(Noh* option){
    lcd.setCursor(0, 0);
    lcd.print(option->name);
    lcd.setCursor(15, 0);
    lcd.print(01111111, BIN); // setinha
    lcd.setCursor(0, 1);
    lcd.print(option->next->name);
}

Noh* context_menu(Noh* option){
    bool in_context_page = true;
    Noh* last_page = option;
    if (option->leads_to_another_menu){ // se é apenas navegação, e não uma alteração
        while (in_context_page){
            switch (read_LCD_buttons){
                case btnNONE:
                    break;
                case btnUP:
                    // volta para a opção anterior
                    option = option->previous;
                    print_menu(option);
                    break;
                case btnDOWN:
                    // vai para a próxima opção
                    option = option->next;
                    print_menu(option);
                    break;
                case btnLEFT:
                    // retorna para a página anterior
                    in_context_page = false;
                    break;
                default:
                    // seleciona a opção atual
                    option = context_menu((Noh*)(option->data));
                    print_menu(option);
            }
        }
        return last_page;
    }
}

void setup() {
    lcd.begin(16, 2);              // start the library
    lcd.setCursor(0,0);
}

void loop() {
    // put your main code here, to run repeatedly:
}