LED widget local value problem

How-to
1

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Description

I set local values for two LEDs, but the values are not as intended.

What MCU/Processor/Board and compiler are you using?

Visual studio 2019

What LVGL version are you using?

7.10

What do you want to achieve?

What have you tried so far?

Code to reproduce

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main.c (15.8 KB)

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LVGL Simmulation

2

It would be helpful if you explained what exactly is “not as intended”.

1 Like
3

Hi jupeos

Green_led is “OK: %d” and red_led is “NG: %d”. Two LEDs are displayed as OK or NG at the same time.
Please refer to the code below.

sprintf(char_buff, “NG : %d”, 0);
lv_obj_set_style_local_value_str(led_red, LV_LED_PART_MAIN, LV_STATE_DEFAULT, char_buff);

sprintf(char_buff, “OK : %d”, 0);
lv_obj_set_style_local_value_str(led_green, LV_LED_PART_MAIN, LV_STATE_DEFAULT, char_buff);

Thank you for your interest.

4

I think it’s because you are using the same buffer (char_buff) for both.

5

I agree with @embeddedt. You need to make your buffers persistent beyond the scope of this function, too. From the style docs

value_str ( const char * ): Pointer to text to display. Only the pointer is saved! (Don’t use local variable with lv_style_set_value_str, instead use static, global or dynamically allocated data).

6

Solved using two different buffers.
thanks.