How to access Flutter Back button functionality?

问题:

I would like to present an AdWords interstitial before the user returns to the previous page. How can I do this when the return button is pressed?

回答1:

I think you can make use of WillPopScope widget. You can pass a callback function which will be called when the view is about pop. Just do whatever tasks to be completed before pop and then return true.

Example:

Future<bool> _willPopCallback() async {
    // await showDialog or Show add banners or whatever
    // then
    return true; // return true if the route to be popped
}


//then pass the callback to WillPopScope
new WillPopScope(child: new Scaffold(), onWillPop: _willPopCallback)

Hope that helps!