1.直接在Row中使用TextField或者TextFormField会报错
======== Exception caught by rendering library =====================================================
The following assertion was thrown during paint():
RenderBox was not laid out: RenderRepaintBoundary#72e67 NEEDS-LAYOUT NEEDS-PAINT
'package:flutter/src/rendering/box.dart':
Failed assertion: line 1982 pos 12: 'hasSize'
Either the assertion indicates an error in the framework itself, or we should provide substantially more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
解决办法
Row(children: <Widget>[new Expanded(child: TextField())],)
