How does Flutter top up the input method with the bottom chat input field

@override Widget buildWidget(BuildContext context) { // TODO: implement buildWidget controller = new ScrollController(); return new StreamBuilder( stream: bloc.stream, builder: (BuildContext context, AsyncSnapshot<List> snapshot) { return Column( mainAxisSize: MainAxisSize.max, children: [ Expanded( child: EasyRefresh.custom( firstRefresh: true, reverse: false, scrollController: controller, header: CustomBallPulseHeader(), onRefresh: () async { return Future.delayed(Duration(milliseconds: 2000), () { bloc.onLoadMore( context: context, controller: controller); }); }, slivers: [ SliverList( delegate: SliverChildBuilderDelegate( (context, index) { T item = snapshot.data[index]; return buildItem(context, item); }, childCount: snapshot.data == null ? 0 : snapshot.data.length, ), ), ]), flex: 1, ), getFooterWidget(context) ], ); }); }

getFooterWidget(BuildContext context) { // TODO: implement getFooterWidget return Container( color: Colors.grey[100], margin: EdgeInsets.only(bottom: MediaQuery.of(context).viewInsets.bottom), padding: EdgeInsets. Only (left: 15.0, right: 15.0, top: 8.0, bottom: 8.0,), child: Row(children: [Expanded(Flex: 1, child: Container(padding: EdgeInsets. Only (left: 5.0, right: 5.0, top: 5.0, bottom: 5.0,), decoration: BoxDecoration(color: RGB (50, 50, 50)) Colors. White, borderRadius: Borderradius.all (radius.circular (4.0,)),), Child :TextField(Controller: _textEditingController, decoration: InputDecoration(contentPadding: EdgeInsets. Only (top: 2.0, bottom: 2.0,), border: InputBorder.none, ), onSubmitted: (value) { if (_textEditingController.text.isNotEmpty) { _textEditingController.text = ”; } }, ), ), ), InkWell( onTap: () { if (_textEditingController.text.isNotEmpty) { bloc.sendMessage(_textEditingController.text); _textEditingController. Text = ‘ ‘;}}, child: Container (height: 30.0, width: 60.0, alignment: Alignment. Center, margin: EdgeInsets. Only (left: 15.0,), align: BoxDecoration(color: RGB (50, 50, 50)) _textEditingController.text.isEmpty ? Colors.grey : Colors.green, borderRadius: Borderradio.all (radio.circular (4.0,)),), Child: Text(” send “, style: TextStyle(color: colors.white, fontSize: (), (), (,], (,), (; }