An error called "Null check operator used on a null value" appeared to use flutter 'custom_info_window: ^1.0.1'. How should I solve this?

Solution 1:

You are using force-unwrap (exclamation-mark !) here : _customInfoWindowController.addInfoWindow!(

instead of using force-unwrap make it optional by using ? and providing a default value so whenever it is null the app won't crash.