Flutter: unloaded widgets when starting the app & unresponsive widgets - flutter

Question

for a while now, I was trying to learn Flutter for mobile development. So, everything is straight forward and easy to grasp.
But, the following issues I cannot seem to solve:
Resizing the CircleAvatar() in the AppBar: I tried using scale, size, nothing worked.
Whatever I added after the 1st ListView.builder(), the emulator does not read/ display
my flutter is up-to-date and no errors/issues are shown when I run flutter doctor or my run the app.
Thanks
Code Used:
class MessageScreen extends StatefulWidget {
static Route<dynamic> route() => MaterialPageRoute(
builder: (context) => MessageScreen(),
);
#override
_MessageScreenState createState() => _MessageScreenState();
}
class _MessageScreenState extends State<MessageScreen> {
String tempLink =
'https://images.unsplash.com/photo-1599566150163-29194dcaad36?ixid=MXwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHw%3D&ixlib=rb-1.2.1&auto=format&fit=crop&w=634&q=80';
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: Colors.blue[400],
appBar: AppBar(
elevation: 0.0,
leading: CircleAvatar(
backgroundImage: NetworkImage(tempLink),
radius: 15.0,
child: tempLink == null ? Text('HH') : null,
),
title: Text('Chats'),
backgroundColor: Colors.blue[400],
actions: [
IconButton(
onPressed: () {},
icon: Icon(Icons.search),
),
],
),
body: Column(
children: [
Row(
children: [
Container(
child: ListView.builder(
itemCount: newMatching.length,
padding: EdgeInsets.only(left: 6),
scrollDirection: Axis.horizontal,
itemBuilder: (BuildContext context, int index) {
return GestureDetector(
onTap: () => Navigator.push(
context,
MaterialPageRoute(
builder: (_) => ChatScreen(
user: newMatching[index],
),
),
),
child: _profileButton(tempLink),
);
},
),
),
],
),
SizedBox(
height: 18,
),
Container(
decoration: BoxDecoration(
color: Colors.white,
borderRadius: BorderRadius.only(
topLeft: Radius.circular(20), topRight: Radius.circular(20)),
),
child: ListView.builder(
itemCount: chats.length,
itemBuilder: (BuildContext context, int index) {
final Message chat = chats[index];
return GestureDetector(
onTap: () => Navigator.push(
context,
MaterialPageRoute(
builder: (_) => ChatScreen(
user: chat.sender,
),
),
),
child: Container(
margin: EdgeInsets.only(top: 5, bottom: 5, right: 1),
padding:
EdgeInsets.symmetric(horizontal: 2, vertical: 5),
decoration: BoxDecoration(
color: chat.unread ? Color(0xFFFFEFEE) : Colors.white,
borderRadius: BorderRadius.only(
topRight: Radius.circular(20.0),
bottomRight: Radius.circular(20.0),
),
),
child: _chatNavigatorButton(
chat.sender.imgAvatar,
chat.sender.fname,
chat.text,
chat.time,
chat.unread)),
);
}),
),
],
),
);
}
}

Answer 1

Try wrapping the CircleAvatar with a Container:
Container(height: 10, width: 10, child: CircleAvatar(...))
Is there a chance that chats simply has the length of 0 and no elements? Maybe the second ListView.builder() does display correctly but includes no items. At least that's what I can retrieve from the given code.