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Python Polling

Sahar Nasiri
Sahar Nasiri
7,454 Points
Posted by Sahar Nasiri
Sahar Nasiri
7,454 Points

Trace

I didn't understand what exactly this line does and why do we need it? Why does my timer_text disappear when I comment this line?

self.timer_text.trace("w", self.build_timer)

1 Answer

Wairton Rebouças
Wairton Rebouças
8,225 Points
Wairton Rebouças
Wairton Rebouças
8,225 Points

self.timer_text.trace("w", self.build_timer) Trace is a method to add an observer to timer_text, in this case, whenever you modify timer_text variable, self.build_timer method will be called. Since this method is used to build your timer, if you comment it, your timer will never be built.

More resources:

stringvar and trace effbot site

Observer pattern on wikipedia