Shared Preference Flutter(How to use Shared preference in build method)

Question

Hi I'm new to flutter and I'm struggling to use shared preference inside the builder method, Here is my code:

getId() async {
      SharedPreferences prefs = await SharedPreferences.getInstance();
      String sessionId = prefs.getString('sessionId');
      return Text(sessionId);
    }

This is a piece of my build method:

ListTile(
                  title: Text(
                    'Welcome, $getId()',
                    style: TextStyle(color: Colors.white),
                  ),

Here's the error output that I get for trying to use the shared pref inside a text widget:

dynamic function closure flutter

The important part for you is the "how do I use it" part. although it cannot hurt to brush up on the other details as well. — nvoigt, May 10 '21 at 06:46

score 0 · Answer 1 · answered May 10 '21 at 06:42

You can use the FutureBuilder widget

Example:

FutureBuilder(
      future: getId(),
      builder: (context, snapshot) {
        if (snapshot.hasData){
          return ListTile(
              title: Text(
                'Welcome, ${snapshot.data}',
                style: TextStyle(color: Colors.white),
              ),
        }else if (snapshot.hasError){
          return Container(); //Error getting data
        }else{
          return Container(); //show Loading
        }
      },);

And in your getId() return String instead of a Text Widget Example:

getId() async {
      SharedPreferences prefs = await SharedPreferences.getInstance();
      String sessionId = prefs.getString('sessionId');
      return sessionId;
    }

score 0 · Answer 2 · answered May 10 '21 at 06:53

call getId function in initState to assign value to the variable "id".

@override
 void initState() {
 super.initState();
 getId.then((value) => setState(() {
      id = value;
    }));
}

In your build method

  ListTile(
              title: Text(
                'Welcome, $id',
                style: TextStyle(color: Colors.white),
              ),

Your getId function will return string

getId() async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  String sessionId = prefs.getString('sessionId');
  return sessionId;
}

Shared Preference Flutter(How to use Shared preference in build method)

2 Answers2