Error with Calling Teensy library from custom library - Teensy ILI9341

Development Libraries
1

Hi

I am newbie to trying to create user/custom libraries. I am currently trying to make a GUI library for some of my students to use, I teach in engineering(I am more in materials) but am certainly not a real programmer. I have made a couple libraries in the past but never tried to call a separate library to use in the one I am creating. I get several errors about redefining, member function with out object, ect. I tried a bunch of different approaches and basically just traded one error for another.

If anyone can take a look the header file, cpp file, and sketch (sketch file should be ok, lol I think). I would really appreciate the help. There are several functions, if you guys can just help me fix the first one I can follow up on all the rest. I am also trying to increase my programming skills/knowledge so if anyone also has some good links or a suggested book, that too would be great.

I am not sure if I should attach the teensy library files I am trying to call or not. If so I will upload. I did not attach because I know the problem is not there, Paul is awsome.

GuiEasy.h (2.61 KB)

GuiEasy.h (2.61 KB)

example_library.ino (2.39 KB)

2

You attached the header file two times.
You attached the source file zero times.
You attached the error file zero times.

Going to be real hard to help you.

3

Hi Paul

Lol, well I feel like a real dummy. Thank you for pointing that out, don't know how I missed that. I also did not even think to upload the error file, that was a good suggestion.
So round two. Here is the correct files this time and thank you for taking a look.

GuiEasy.cpp (7.68 KB)

example_library.ino (2.39 KB)

GuiEasy.h (2.61 KB)

Error_file.txt (1.71 KB)

4

Why is this:

#ifndef ILI9341_t3H
#define ILI9341_t3H

in your GuiEasy.h file?

  public:
    bool s, p;  //act as temp storage, s = status, p = pressed

These fields should NOT be public. You should have, if it is meaningful, methods to get and set these private fields.

ILI9341_t3 tft;

The compiler is saying that you can't declare an instance of the ILI9341_t3 class this way, because the class does not have a no-argument constructor.

The examples that are provided with the library use code like:

#define TFT_CS 10
#define TFT_DC  9
ILI9341_t3 tft = ILI9341_t3(TFT_CS, TFT_DC);

If the idea is that your class should be aware of an instance of the ILI9341_t3 class defined elsewhere, the line in your GuiEasy.cpp file should be

extern ILI9341_t3 tft;
5

The
#ifndef ILI9341_t3H
#define ILI9341_t3H
part was from a previous attempt to fix the multiple redefining of of ILI9341_t3 tft. I had seen the idea in some other searches and tried it.

The variables in the public class are just place holders, I also have private versions _s, _p. I just did not include that in this version. (there are actually quite a few more variables and functions to the overall library I am trying to make. This "practice" version was to try to learn how to call an external library from within my library.) With that said, I do appreciate the advise on not allowing those variables to be only public and fully agree with you on that.

Now to the excellent fix. The extern ILI9341_t3 tft; was the idea/command I was trying to get to. That is why I had it defined as ILI9341_t3 tft, in the .cpp file. I was just not aware I needed the extern command first. (toward the other comment, I have it defined ILI9341_t3 tft = ILI9341_t3(TFT_CS, TFT_DC); in the .ino file. I read/looked over the examples, .h, and .cpp files that you provided with the original ILI9341_t3 library)

Thank you very much for the help, it is greatly appreciated. That was exactly what I was missing.

Also as a side note, as a professor I love the teensy for our senior design projects, it is a very capable little board. We tried the audio board this year as well and it too is a great add-on. I think you guys do great work, keep it up. We definitely are going to continue to use your products. If you would ever have any interest in doing a collaboration with our senior design class we would love to work with you guys. We are also always on the hunt for any new potential "cool" topics/projects for the students to try, if you have any suggestions I would also be grateful to hear them.

6

Paul Stoffregen and I may share the same first name, and same first letter in our last names, but we are most definitely not the same person. I'm the taller one.