How to fix Instance of Future<int> in appbar title in Flutter?-CodePudding

I would like the appBar title of my Scaffold to display the total number of items (length) in a Firebase Query at launch, but it keeps returning Instance of 'Future<int>'. How can I fix this?

Here's my code:

Query itemList = FirebaseFirestore.instance
      .collection('simple');
      
Future<int> itemCount() async => FirebaseFirestore.instance
      .collection('simple')
      .snapshots()
      .length;
      
...      

    return Scaffold(

            appBar: AppBar(
              title: Text("# Items: "   itemCount().toString()),
              
              // DISPLAYS: # Items: Instance of 'Future<int>'

Unfortunately, it displays Instance of 'Future<int>'. What do I have to change to obtain the item count (length) and have that show-up in the title text?

Thank you!

CodePudding user response：

You can use a FutureBuilder like this :

AppBar(
    title: FutureBuilder<String>(
           future: itemCount(), 
           builder: (BuildContext context, AsyncSnapshot<int> snapshot) {
               if (snapshot.hasData) {
                  return Text("# Items: "   snapshot.data.toString());
               }else {
                  Text("No data");
               }
           }),
     )

CodePudding user response：

You are calling a "Future" function, thats the function return a Future so you cant display it like that, you need to use an await (if you are in async function) or a .then() (if you'r not in async function). The best way to print it in your case is to use a FutureBuilder or the keyword await.