How can I know if I leave the screen already with tab navigation (react-navigation)?

Question

I am using react navigation (tab navigation) for my app. But how can I know if I leave the screen already?

For example, I have Screen A and Screen B. And I have a timer in my screen A but when I click Screen B, I want the timer stop. Before I use react navigation, I can simply use componentWillunmount function. However, I think when I use tab navigation, the first screen (Screen A) hasn't been destroy or unmount when I go to the screen B.

Any ideas? Thanks!

Answer 1

对于Tab Navigator，您可以使用特殊事件来定义当前的活动屏幕以及“焦点”和“模糊”之类的事件