Expected a value of type ‘String’, but got one of type ‘Null’

Learn how to fix the ‘Expected a value of type ‘String’, but got one of type ‘Null” error in your code. Our step-by-step guide provides easy-to-follow solutions to ensure your code runs smoothly.

Fix Expected a value of type ‘String’, but got one of type ‘Null’

This is a common type of error when using the MaterialPageRoute when navigation one page to second screen. Pass the same value what is expecting from the navigation page on the case of id.

Error

For example :

I tired to pass id from snap value like this from first screen to second screen :

Navigator.push(

 context,

 MaterialPageRoute(

   builder: (context) => SecondScreen(

     itemId: value[‘itemId’],

     title: value['title'] ?? "",

     content: value["content"],

   ),

 ),

);

It complain me ,: Expected a value of type ‘String’, but got one of type ‘Null’

Check Out: [Solved] Incorrect use of ParentDataWidget in Flutter

Solution

So tired to there like this:   

Navigator.push(

 context,

 MaterialPageRoute(

   builder: (context) => ChapterContentScreen(

     itemId: widget.itemId,// id getting from previous screen to this screen and again passed from here to next screen

     title: value['title'] ?? "",

     content: value["content"],

   ),

 ),

);

It’s worked fine for me.