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[on:]

so, i've got my little "menu" library and was trying to make it works when suddenly, after a little modification, it said: 'LiquidCrystal' was not declared in this scope
after a little debugging i realized that the problem could be in the way i attached the liquidcrystal library into my library. the question is: how should i include the liquidcrystal library into mine?

[Reply #1 on:]

the question is: how should i include the liquidcrystal library into mine?

No, the question is how DID you include the LiquidCrystal library? And, did you include the LiquidCrystal header file in your sketch?

You are not allowed to hide the use of a library.

[Reply #2 on:]

when i included the LiquidCyristal library in the my_menu.h library it didn't work, and so if the inclusion was in the .cpp file. i also get the same error if i don't include thwe library, nowhere.

[Reply #3 on:]

when i included the LiquidCyristal library in the my_menu.h library it didn't work

"it didn't work" has to be the most overused phrase on this forum. It doesn't tell us anything.

"When I use this code, it fails to compile, with this error message" tells us something.

"When I use this code, it compiles, but nothing appears on the LCD when I run the code" tells us something.

"it didn't work" tells us nothing.

i also get the same error if i don't include thwe library, nowhere.

Lucky you.

If you care to quit dancing around, and post some code and error messages, we'll be happy to help.

[Reply #4 on:]

as i've said on the first post, i get the " 'LiquidCrystal' was not declared in this scope " message. so, here's the code for the header:

#ifndef MenuLCD_h
#define MenuLCD_h

#include "Arduino.h"

// identificatori degli stati (bottoni e stato di idle)
#define UP   0
#define DOWN 6
#define SEL  2
#define BACK 4
#define IDLE 10

class MenuLCD
{
  public:
    typedef struct           // database menù
    {
      byte id;               // PK: identificatore univoco della voce
      byte id_par;           // FK: riferimento al menu genitore della voce
      char str[18];          // Stringa contenente il testo visualizzato
    } MenuItem;
    MenuLCD(byte rs,
            byte enable,
            byte d4,
            byte d5,
            byte d6,
            byte d7,
            String intro,
            MenuItem _menu
    ); 
    MenuItem menu;           // Database contenente le voci del menù
    byte menu_lenght;        // Numero di voci del menu
    byte current_menu;       // Menu corrente
    byte current_sel;        // Voce attualmente selezionata
    byte pin;                // Pin della pulsantiera
    boolean sthToDo;         // Necessità di eseguire azioni
    String intro_str;        // Stringa contentente l'intro
    byte getFirstOption(byte submenu);
    byte getLastOption(byte submenu);
    byte getPreviousMenu(byte submenu);
    String getMenuTitle(byte submenu);
    void showIntro();
    void showMenu();
    virtual void doSomething(byte action);
    byte buttonCheck();
    void editSetting(String title, String descr, byte *val, char *list[]);
    void editSetting(String title, String descr, byte *val, byte min, byte max);
    
  private:
    static byte sel_dot[8];    // Carattere indicante la selezione
    byte old_menu;             // Menu precedente
    byte old_sel;              // Voce precedentemente selezionata
    boolean old_sthToDo;       // Stato precedente di sthToDo
    void menuPrint(byte submenu, byte sel);
    
    
};

#endif

and here's the one for the MenuLCD.cpp file:

#include "MenuLCD.h"

MenuLCD::MenuLCD(byte rs, byte enable, byte d4, byte d5, byte d6, byte d7, String intro, MenuItem _menu)
{
  // inizializza le variabili della navigazione
  current_menu = 0;
  current_sel = 1;
  sthToDo = false;
  old_menu = 255;
  old_sel = 255;
  old_sthToDo = false;
  // inizializza il display
  LiquidCrystal lcd(rs, enable, d4, d5, d6, d7);
  menu_lenght = sizeof(_menu)/sizeof(MenuItem);
  lcd.begin(20, 4);
  // inizializza il carattere per la selezione
  sel_dot[0] = B00000;
  sel_dot[1] = B00100;
  sel_dot[2] = B01110;
  sel_dot[3] = B11111;
  sel_dot[4] = B01110;
  sel_dot[5] = B00100;
  sel_dot[6] = B00000;
  lcd.createChar(1, sel_dot);
}

i've tried to put the #include <LiquidCrystal.h> in both of them, using various combination, but nothing changed: all i've got was that error message. by the way, this is the complete compilation log:

In file included from MenuLCD.cpp:7:
/MenuLCD.h:11:27: error: LiquidCrystal.h: No such file or directory
MenuLCD.cpp: In constructor 'MenuLCD::MenuLCD(byte, byte, byte, byte, byte, byte, String, MenuLCD::MenuItem)':
MenuLCD.cpp:18: error: 'LiquidCrystal' was not declared in this scope
MenuLCD.cpp:18: error: expected `;' before 'lcd'
MenuLCD.cpp:20: error: 'lcd' was not declared in this scope

[Reply #5 on:]

White space is nice. It can be used to make your code more readable.

Unless I am going blind, I don't see that the header file includes LiquidCrystal.h anywhere. Nor, do I see that the source file includes it, either.

Nor, do I see the sketch that uses the MenuLCD library.

[Reply #6 on:]

i think you're going blind, because after the two pieces of code i said:

i've tried to put the #include <LiquidCrystal.h> in both of them, using various combination, but nothing changed: all i've got was that error message. by the way, this is the complete compilation log:

i thought it was enough self-explanatory.
also, i don't see how the problem could stay in the sketch file.

[Reply #7 on:]

also, i don't see how the problem could stay in the sketch file.

Then, you don't understand the build process.

All files in the sketch directory are copied to a temp, directory for the build process. All include files referenced by the sketch are copied to that temp. directory, too, along with the associated source files.

Only the stuff in that temp. directory is involved in the build.

So, if sketch.pde (or .ino) does not include LiquidCrystal.h, LiquidCrystal.h and LiquidCrystal.cpp are NOT copied to the temp. directory, and are not available for MenuLCD to include.

[Reply #8 on:]

it means that the LiquidCrystal.h library has to be included in both the sketch and the library .h file?

[Reply #9 on:]

it means that the LiquidCrystal.h library has to be included in both the sketch and the library .h file?

Yes. See reply #1.

[Reply #10 on:]

ok, that's weird. it looks so redundant :/

however, thanks a lot! can i ask you a little bit of help?

i've just added this code:

// menuPrint
// stampa il menù sul display
// submenu: id del menu da stampare
// sel: id della voce da evidenziare
void menuPrint(byte submenu, byte sel)
{
  byte screen_line = 0;
  byte i;
  String titolo;
  
  lcd.clear();
  lcd.setCursor(0, screen_line);
  for(i=0; i<menu_lenght; i++)
  {
    if(menu.id == submenu)
    {
      titolo=menu.str;
      titolo.toUpperCase();
      lcd.print(titolo);
      screen_line++;
    }
    
    if(menu.id_par == submenu)
    {
      if(menu.id == sel)
      {
        lcd.setCursor(0, screen_line);
        lcd.write(1);
        lcd.print(" ");
        lcd.print(menu.str);
      }
      else
      {
        lcd.setCursor(2, screen_line);
        lcd.print(menu.str);
      }
      screen_line++;
    }
  }
}

to my menuLCD.cpp file, just after the constructor declaration (see the code posted above). when trying to compile, it says that "lcd was not declared in this scope" (on the line   lcd.clear(). then i thought "that's ok, it's because the "lcd" is declared into the constructor, allowing me only to use it as long as my constructor is running". so i put the "LiquidCrystal lcd;" in the .h file, among the other variables declarations, but then the compiler says : 'LiquidCrystal' does not name a type.

i have no idea of how to initialize the screen (my lcd variable) in order to use it in all my other methods.

[Reply #11 on:]

ok, that's weird. it looks so redundant :/

Yes, and no. It simplifies the build process, for one thing. For another, it prevents you from using a library that uses a library that uses a library that (tries to) use a library that you don't have.

Declare up front that your sketch will need library A, B, C, and D. No need to chase after libraries. All required libraries are defined up front.

to my menuLCD.cpp file, just after the constructor declaration (see the code posted above). when trying to compile, it says that "lcd was not declared in this scope" (on the line   lcd.clear()smiley-wink. then i thought "that's ok, it's because the "lcd" is declared into the constructor, allowing me only to use it as long as my constructor is running". so i put the "LiquidCrystal lcd;" in the .h file, among the other variables declarations, but then the compiler says : 'LiquidCrystal' does not name a type.

You do need to move the declaration and initialization of the instance out of the constructor. As you have discovered, a local variable in the constructor is of no use to the rest of the class.

You need to add a line to the header file that says that lcd is an instance of the LiquidCrystal class. The, it needs to be instanced/valued at the same time as the constructor of your class is called:

Code:

MenuLCD::MenuLCD(byte rs, byte enable, byte d4, byte d5, byte d6, byte d7, String intro, MenuItem _menu), lcd(rs, enable, d4, d5, d6, d7)

[Reply #12 on:]

You need to add a line to the header file that says that lcd is an instance of the LiquidCrystal class. The, it needs to be instanced/valued at the same time as the constructor of your class is called:

Code:

MenuLCD::MenuLCD(byte rs, byte enable, byte d4, byte d5, byte d6, byte d7, String intro, MenuItem _menu), lcd(rs, enable, d4, d5, d6, d7)

to be honest, i didn't understand. how can i say that lcd is an instance of LiquidCrystal?

[Reply #13 on:]

how can i say that lcd is an instance of LiquidCrystal?

Code:

LiquidCrystal lcd;

[Reply #14 on:]

nive. so i added the LiquidCrystal lcd;  statement among all the other declarations in the MenuLCD.h, then, i modified my MenuLCD.cpp constructor like this:

Code:

MenuLCD::MenuLCD(byte rs, byte enable, byte d4, byte d5, byte d6, byte d7, String intro, MenuItem _menu), lcd(rs, enable, d4, d5, d6, d7)
{
  // inizializza le variabili della navigazione
  current_menu = 0;
  current_sel = 1;
  sthToDo = false;
  [all the rest]

but the compiler says:

MenuLCD.cpp:8: error: declaration of 'MenuLCD::MenuLCD(byte, byte, byte, byte, byte, byte, String, MenuLCD::MenuItem)' outside of class is not definition
MenuLCD.cpp:8: error: expected constructor, destructor, or type conversion before '(' token