1.
class ListFormState extends State<ListForm> { List<String> products = ["Test1", "Test2", "Test3"]; @override Widget build(BuildContext context) { return new Container( child: new Center( child: new Column( children: <Widget>[ new Row( children: <Widget>[ new ListView.builder( itemCount: products.length, itemBuilder: (BuildContext ctxt, int index) { return new Text(products[index]); } ), new IconButton( icon: Icon(Icons.remove_circle), onPressed: () { }, ) ], mainAxisAlignment: MainAxisAlignment.spaceBetween, ), new TextField([ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: Cannot hit test a render box with no size. The hitTest() method was called on this RenderBox:
解答：The problem is that you are placing the ListView inside a Column/Row. The text in the exception gives a good explanation of the error.
To avoid the error you need to provide a size to the ListView inside.
I propose you this code that uses an Expanded to inform the horizontal size (maximum available) and the SizedBox (Could be a Container) for the height:
new Row( children: <Widget>[ Expanded( child: SizedBox( height: 200.0, child: new ListView.builder( scrollDirection: Axis.horizontal, itemCount: products.length, itemBuilder: (BuildContext ctxt, int index) { return new Text(products[index]); }, ), ), ), new IconButton( icon: Icon(Icons.remove_circle), onPressed: () {}, ), ], mainAxisAlignment: MainAxisAlignment.spaceBetween, )
