Keyboard widget, how to convert Unicode char* from to char*

[NGune.1]

Hi,

I am trying to use keyboard widget in TouchGfx 4.21. I have global

char *name;

variable. After a lot of trial, I couldn't find a way to copy the value returned by keyboard.getBuffer() to my global variable. I even tried to convert to UTF-8 first, but no success.

Briefly, I just want to store the value returned by keyboard.getBuffer() to my global variable.

Can somebody help please?

Thanks

[Yoann KLEIN]

Hello @NGune.1​,

Did you already try with the strncpy() method ?

Otherwise, with simply casting the UnicodeChar* to char*, like : (char*)UnicodeChar*.

/Yoann

[NGune.1]

Hi Yoann,

Thanks for your reply.

With this:

strncpy(*name, keyboard.getBuffer(), 11);

I get :

error: cannot convert 'touchgfx::Unicode::UnicodeChar*' {aka 'short unsigned int*'} to 'const char*'

If I first convert to utf-8 :

Unicode::toUTF8(keyboard.getBuffer(), buff, 11);
strncpy(*name, buff, 11);

I get:

error: invalid conversion from 'uint8_t*' {aka 'unsigned char*'} to 'const char*' [-fpermissive]

if "buff" is defined as uint8_t *buff;

and I get:

error: invalid conversion from 'char*' to 'uint8_t*' {aka 'unsigned char*'} [-fpermissive]

if "buff" is defined as char *buff;

[Yoann KLEIN]

Hi,

I just did that this cast between a UnicodeChar* and a char* and it seems to work, at least it does not trigger any compilation issues :

touchgfx::Unicode::UnicodeChar* unicodeChar = textArea1Buffer;
char* test = (char*)unicodeChar;

Could you try to reproduce that in your project ?

/Yoann

[Piranha]

By the way, strncpy() is not usable for normal string copying. Read what it actually does:

https://en.cppreference.com/w/c/string/byte/strncpy

If count is reached before the entire array src was copied, the resulting character array is not null-terminated.

If, after copying the terminating null character from src, count is not reached, additional null characters are written to dest until the total of count characters have been written.

[NGune.1]

Hi Yoann,

Thank you for your suggestion. Yes, it took me one step further. I mean, with your solution I didn't get any compiler error. However, in the end, the variable 'test' contains only the first entry, although I can see the entered text is entirely buffered.

I tried both:

char* test = (char*)keyboard.getBuffer();

and

char* test;
strncpy(test, (char*)keyboard.getBuffer(), 11);

but the result is the same.

Could you please check the attached screenshot?

There are two buffers. I marked them as 1 and 2 in the picture. I entered "ABCD" using the touch keyboard. In the first buffer there is only "A", but the second one contains "ABCD". I think, for some reason keyboard.getBuffer() returns only the first entry, or I am doing something wrong.

What may be the reason for this situation?

Thanks,