How to fix Textfield height? - flutter

Question

As you can see, the height is different.
The picture on the left shows the app running when the keyboard did not pop up. And the picture on the right shows the app running when keyboard pops up and clicks "Flutter Hot Reload"(Android Studio).
I want the textfield to be like the picture on the right without keyboard pop-up.
How can I fix this?
Appbar
class CustomAppbar extends StatelessWidget with PreferredSizeWidget{
#override
final Size preferredSize;
#override
static double height = AppBar().preferredSize.height;
CustomAppbar() : preferredSize = Size.fromHeight(height);
#override
Widget build(BuildContext context) {
#override
final double statusbarHeight = MediaQuery.of(context).padding.top;
return Container(
child: Stack(
children: <Widget>[
AppBar(
backgroundColor: Colors.white,
elevation: 0,
iconTheme: IconThemeData(color: Colors.black,),
),
Container(
decoration: BoxDecoration(
color: Colors.grey,
borderRadius: BorderRadius.all(Radius.circular(10))
),
margin: EdgeInsets.only(left: 60, top: statusbarHeight + 5, bottom: 5, right: 5),
child: InputBox(),
)
],
),
);
}
}
InputBox
class InputBox extends StatefulWidget {
#override
_InputBoxState createState() => _InputBoxState();
}
class _InputBoxState extends State<InputBox> {
TextEditingController _SearchController = TextEditingController();
FocusNode _focusNode = FocusNode();
String _SearchText = "";
_InputBoxState(){
_SearchController.addListener(() {
setState((){
_SearchText = _SearchController.text;
});
});
}
#override
Widget build(BuildContext context) {
return TextField(
focusNode: _focusNode,
style: TextStyle(fontSize: 19),
controller: _SearchController,
decoration: InputDecoration(
hintText: "Search",
border: InputBorder.none,
prefixIcon: Icon(Icons.search, color: Colors.white,),
suffixIcon: _focusNode.hasFocus ? IconButton(
icon: Icon(Icons.cancel, color: Colors.white,),
onPressed: (){
setState((){
_SearchController.clear();
_SearchText = "";
_focusNode.unfocus();
});
},
) : Container()
)
);
}
}

Answer 1

style:TextStyle(height: 20), //custome height
decoration: InputDecoration(
isDense: true) // remove padding inside textfield
you can use ContentPadding if you want give padding inside textfield