Why aren't my apps showing anything after i added list tile

import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
class Reservation extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    final appTitle = 'Car Reservation';
    return MaterialApp(
      title: appTitle,
      home: Scaffold(
        appBar: AppBar(
          title: Text(appTitle),
        ),
        body: MyCustomForm(),
      ),
    );
  }
}
// Create a Form widget.
class MyCustomForm extends StatefulWidget {
  @override
  MyCustomFormState createState() {
    return MyCustomFormState();
  }
}
// Create a corresponding State class. This class holds data related to the form.
class MyCustomFormState extends State<MyCustomForm> {
  // Create a global key that uniquely identifies the Form widget
  // and allows validation of the form.
  final _formKey = GlobalKey<FormState>();

  @override
  Widget build(BuildContext context) {
    // Build a Form widget using the _formKey created above.
    return Form(
      key: _formKey,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: <Widget>[
          TextFormField(
            decoration: const InputDecoration(
              icon: const Icon(Icons.person),
              hintText: 'Enter your name',
              labelText: 'Name',
            ),
          ),
          TextFormField(
            decoration: const InputDecoration(
              icon: const Icon(Icons.phone),
              hintText: 'Enter a phone number',
              labelText: 'Phone',
            ),
          ),
          TextFormField(
            decoration: const InputDecoration(
              icon: const Icon(Icons.car_repair_outlined),
              hintText: 'Enter your car plate',
              labelText: 'Plate Number',
            ),
          ),
          TextFormField(
            decoration: const InputDecoration(
              icon: const Icon(Icons.punch_clock),
              hintText: 'How many hours',
              labelText: 'Hours',
            ),
          ),
          TextFormField(
            decoration: const InputDecoration(
              icon: const Icon(Icons.space_bar),
              hintText: '',
              labelText: 'Reservation Spot create as ListTile',
            ),
          ),
          ListView(
            children: const <Widget>[
              Card(child: ListTile(title: Text('One-line ListTile'))),
              Card(
                child: ListTile(
                  leading: FlutterLogo(),
                  title: Text('One-line with leading widget'),
                ),
              ),
              Card(
                child: ListTile(
                  title: Text('One-line with trailing widget'),
                  trailing: Icon(Icons.more_vert),
                ),
              ),
              Card(
                child: ListTile(
                  leading: FlutterLogo(),
                  title: Text('One-line with both widgets'),
                  trailing: Icon(Icons.more_vert),
                ),
              ),
              Card(
                child: ListTile(
                  title: Text('One-line dense ListTile'),
                  dense: true,
                ),
              ),
              Card(
                child: ListTile(
                  leading: FlutterLogo(size: 56.0),
                  title: Text('Two-line ListTile'),
                  subtitle: Text('Here is a second line'),
                  trailing: Icon(Icons.more_vert),
                ),
              ),
              Card(
                child: ListTile(
                  leading: FlutterLogo(size: 72.0),
                  title: Text('Three-line ListTile'),
                  subtitle: Text(
                      'A sufficiently long subtitle warrants three lines.'
                  ),
                  trailing: Icon(Icons.more_vert),
                  isThreeLine: true,
                ),
              ),
            ],
          ),
          new Container(
              padding: const EdgeInsets.only(left: 40.0, top: 40.0),
              child: new RaisedButton(
                child: const Text('Submit'),
                onPressed: (){},
              )),
        ],
      ),
    );
  }
}

The app won't show after I add the list tile inside, can anyone tell me what went wrong?
Here is after I add my list tile code inside

And here's before I add the list tile code inside

I am wondering if anyone can help me with this one. I still don't understand the flow of it, to be honest.