Keep returning "Instance of 'Future<dynamic>" instead of String (Flutter)

Question

I've looked everywhere and found no solution. I'm wanting to return the result count from a query, yet I'm having troubles. Keep getting "Instance of 'Future" instead of String

I'm using the Singleton pattern.

DB method (database.dart):

    Future<int> getUnCompletedTaskCount () async {
    final db = await database;
    var result = await db.rawQuery("SELECT * FROM Tasks WHERE isComplete = 0");
    int count = Sqflite.firstIntValue(result);
    return count;
  }

My method in main.dart:

    getResultCount () async {
    final value = await DBProvider.db.getUnCompletedTaskCount();
    return value;
  }

Calling the method by:

    getResultCount().toString()

You are using 'async' on your function so You can use FutureBuilder to fetch data from database, api ,... — NoobN3rd
– NoobN3rd, Commented Dec 6, 2019 at 0:09
for FutureBuilder ? on medium.com You can find tons of them. Maybe This one be helpful. If you need help to refactor your code, I'd be happy to help. — NoobN3rd
– NoobN3rd, Commented Dec 6, 2019 at 0:23
I tried that and I think I did it correctly. Now, it's printing the result, but just not displaying it into a Text widget. getResultCount () async { var x; var value = await DBProvider.db.getUnCompletedTaskCount().then((val) { x = val; }); print(x.toString() + "test"); return x; } — Jonathon
– Jonathon, Commented Dec 6, 2019 at 0:30

NoobN3rd · Accepted Answer · 2019-12-06 00:54:17Z

9

I don't know how You're going to use this function, If you need it to get number of completed tasks and then draw something on screen(Like show a list of them or show number of them), I myself use FutureBuilder,Like Below:

FutureBuilder<int>(
  future: getResultCount(),
  builder: (BuildContext context, AsyncSnapshot<int> snapshot) {
    if(snapshot.hasData){
      return Text('Number Of completed : ${snapshot.data}');
    }
    return Container();
  },
)

So when it completely fetch it, it shows a Text Widget, Otherwise it shows nothing(empty Container)

But if you need it in lets say an equation or something, you can do something like this:

  await getResultCount().then((val){
      // do some operation
    });

But again it totaly depends on your code and need.

When you need result of a future function in your code use await before it.

Like getResultCount() use await when You need to use the result of it.

answered Dec 6, 2019 at 0:54

NoobN3rd

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4 Comments

Jonathon Over a year ago

Thanks for the reply. Now, it's saying "build function returned null". Agh, I'm banging my head with this...

NoobN3rd Over a year ago

You should use FutureBuilder as a Widget in somewhere like child,... Because it's like normal widgets, if data isn't fetched completely, it returns Container(), otherwise the Text widget. so if you're using it in Build function, use return before FutureBuilder.

Jonathon Over a year ago

This solved my problem. I left it for a few days, and the solution seemed to have now worked. Thank you!

stanley mbote Over a year ago

thank you. I had a similar instance only that I had not used the await key word

Vrushi Patel · Accepted Answer · 2019-12-06 05:51:23Z

4

Error shows that you are trying to use value of Future<dynamic> as String which it won't let you because value haven't returned yet.
So basically what we have to do here is wait for value to be returned by using then keyword.

Like here.

 getResultCount().then((value){

    });

answered Dec 6, 2019 at 5:51

Vrushi Patel

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Comments

Shadeer · Accepted Answer · 2021-08-20 14:55:19Z

2

On Net Ninja flutter tutorial : User.signInAnon() returns "Future dynamic" ... you should add await in sign_in.dart

  onPressed: () async {
            dynamic result = **await** _auth.signInAnon();

            if (result == null) {
              print('Not signed In');
            } else {
              print('Signed In ');
              print(result);
            }
          },

answered Aug 20, 2021 at 14:55

Shadeer

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