1. We are going to use webview_flutter and version is latest version which is 0.3.7+1.
2. We embed our H5 application to the webview of our flutter application, so far we faced a problem the keyboard can not be popup. the keyboard popup works fine within firefox, chrome or any other browser within mobile device.

here is the information of our flutter development environment.
Flutter 1.5.4-hotfix.2 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 7a4c334 (3 weeks ago) • 2019-04-29 11:05:24 -0700
Engine • revision 52c7a1e
Tools • Dart 2.3.0 (build 2.3.0-dev.0.5 a1668566e5)