CODEWITHSUNDEEP
flutterflutter-layout
x86
x86

Reputation: 519

The return type 'Widget?' isn't a 'Widget', as required by the closure's context

I am using consumer widget to avoid re-rendering before null safety it works fine... But when I upgrade provider package to it gives me an error which I mentioned above it is not accepting ListView.builder() and says that The return type Widget? isn't a Widget, as required by the closure's context


Consumer<GreatPlaces>(
        child: Center(
          child: const Text(
            'Got no places yet, start adding some',
          ),
        ),
        builder: (ctx, greatPlaces, ch) => greatPlaces.items.length <= 0
            ? ch
            : ListView.builder(          ***//Here I got error***
                itemBuilder: (ctx, index) => Center(),
                itemCount: 5,
              ),
      ),

Upvotes: 14

Views: 22760

Answers (4)

Md. Yeasin Sheikh
Md. Yeasin Sheikh

Reputation: 63569

Use null-assert ! operation on ch!

 data.state.length <= 0
          ? child!
          : ListView.builder(
              itemBuilder: (context, index) => Container(),
              itemCount: 4,
            );

Upvotes: 33

Savita Patil
Savita Patil

Reputation: 1

Try adding nullcheck to the ch

body:Consumer<GreatPlaces>(
        child:Center(
        child: Text('Got no places yet, strat adding some!'),
        ),
        builder:(ctx,greatPlaces,ch)=>greatPlaces.items.length<=0 ? 
          ch!:ListView.builder(
          itemCount: greatPlaces.items.length,
          itemBuilder: (ctx,i)=>ListTile(),
      ),
     ));

Upvotes: 0

My Car
My Car

Reputation: 4556

Try the following code:

Consumer<GreatPlaces>(
  child: Center(
    child: const Text(
      'Got no places yet, start adding some',
    ),
  ),
  builder: (ctx, greatPlaces, ch) => greatPlaces.items.length <= 0
      ? ch ?? Container() // You change Container to other widget
      : ListView.builder(
          itemBuilder: (ctx, index) => Center(),
          itemCount: 5,
        ),
),

Upvotes: 0

Kiran Jadhav
Kiran Jadhav

Reputation: 3317

Use below same sample solution ;

  body: Consumer<GreatPlaces>(
    child: const Center(
      child: Text('Got no places yet, start adding some!'),
    ),
    builder: (ctx, greatPlaces, ch) => greatPlaces.items.isEmpty
        ? ch!
        : ListView.builder(
            itemBuilder: (ctx, index) => ListTile(
              leading: CircleAvatar(
                backgroundImage: FileImage(
                  greatPlaces.items[index].image,
                ),
              ),
              title: Text(greatPlaces.items[index].title),
              onTap: () {},
            ),
            itemCount: greatPlaces.items.length,
          ),
  ),

Upvotes: 1

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