Flutter Failed assertion: line 1785 pos 12: ‘hasSize’

Error Failed assertion: line 1785 pos 12:’hasSize’

The reason

1. SingleChildScrollView nested ListView, GridView report errors, SingleChildScrollView and ListView have scrolling. The properties of physics are all scrollable by default.
2. SingleChildScrollView added Expanded or Flexiblez.

Solution

Just add shrinkWrap: true and physics: NeverScrollableScrollPhysics()

SingleChildScrollView(
  child: Column(
    children: <Widget>[
      GridView.count(
        crossAxisCount: 2,
        children: <Widget>[],
        physics: NeverScrollableScrollPhysics(),
        shrinkWrap: true,
      ),
      ListView.builder(
        itemCount: 10,
        itemBuilder: (context, index) {
          return Text("test");
        },
        physics: NeverScrollableScrollPhysics(),
        shrinkWrap: true,
      )
    ],
  ),
)

Fix the height of the parent component

SingleChildScrollView(
    child: ConstrainedBox(
        constraints: BoxConstraints(maxHeight: MediaQuery.of(context).size.height),
        child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: <Widget>[
                Expanded(
                    child: Text('Hello World!'),
                ),
            ],
        ),
    )
)