Button Callback code.

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

Fernando Taddei asked 10 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 10 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 10 months ago				
	
	Yes, it sure did. Thanks.

		

		
							
		

																				
	
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				Sara Santos Staff answered 10 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