Button Callback code.

Q&A Forum › Category: ESP32 › Button Callback code.

Fernando Taddei asked 7 months ago

Could you please explain for the next code segment, how is that the counter variable is initialized to zero, and later incremented. Shouldn’t this result in a counter value always equals to one?
(Page 102 of the book).
Thanks.

if(code == LV_EVENT_CLICKED) {
static uint8_t counter = 0;
counter++;
lv_label_set_text_fmt(label, “Counter: %d”, counter);
LV_LOG_USER(“Counter: %d”, counter);
}


		
		
			Question Tags: LVGL



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				Sara Santos Staff answered 6 months ago				
	
	Hi.

It is because the counter variable is initialized as static.

Learn more about the features of static variables here: https://www.arduino.cc/reference/es/language/variables/variable-scope-qualifiers/static/
I hope this helps.
Regards,

Sara

		

		
							
		

																				
	
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				Fernando Taddei  answered 6 months ago				
	
	Yes, it sure did. Thanks.

		

		
							
		

																				
	
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				Sara Santos Staff answered 6 months ago				
	
	Great.

I’ll mark this issue as resolved. If you need further help, you just need to open a new question in our forum.

Regards,

Sara