Flutter: "Too many positional argument: 0 expected, but 1 found." - flutter-layout

Question

I am new to flutter. I tried to write my first code but got stuck. It says too to change the positional parameter to named parameter but agian it says named parameter already used. Can anyone please help me?
import 'package:flutter/material.dart';
void main() {
runApp( MaterialApp(
debugShowCheckedModeBanner: false,
title: "My app",
home: Scaffold(
appBar: AppBar(
centerTitle: true,
title: const Text("My first App")
),
body: Column(
children: [
Center(child: Image.network("https://images.unsplash.com/photo-1526779259212-
939e64788e3c?ixlib=rb-
1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1474&q=80",
height:300, width: 300,),
const Text('My first app',)
)
],
),
),
)
);
}

Answer 1

The URL is not correct, as the line breaks. And to your error, the Center widget has two children, which is impossible. Thus you had that error. Kindly move the Text Widget out of Center Widget to the Column Widget's children. I also tweaked a bit of your Image.network Widget, to increase the intuitiveness.
void main() {
runApp( MaterialApp(
debugShowCheckedModeBanner: false,
title: "My app",
home: Scaffold(
appBar: AppBar(
centerTitle: true,
title: const Text("My first App")
),
body: Column(
children: [
Center(
child: SizedBox(
height: 300,
width: 300,
child: Image.network("https://images.unsplash.com/photo-1526779259212-939e64788e3c?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1474&q=80",
loadingBuilder: (context, child, loadingProgress) {
if(loadingProgress == null) return child;
return const Center(child: CircularProgressIndicator(),);
},height:300, width: 300),
),
),
const Text('My first app',)
],
),
),
));
}

Answer 2

You need to put url in single line
import 'package:flutter/material.dart';
void main() {
runApp( MaterialApp(
debugShowCheckedModeBanner: false,
title: "My app",
home: Scaffold(
appBar: AppBar(
centerTitle: true,
title: const Text("My first App")
),
body: Column(
children: [
Center(child: Image.network("single line url",
height:300, width: 300,),
const Text('My first app',)
)
],
),
),
)
);
}