RosettaCodeData/Task/User-input-Graphical/Dart/user-input-graphical.dart

90 lines
3.7 KiB
Dart

import 'package:flutter/material.dart';
main() => runApp( OutputLabel() );
class OutputLabel extends StatefulWidget {
@override
_OutputLabelState createState() => _OutputLabelState();
}
class _OutputLabelState extends State<OutputLabel> {
String output = "output"; // This will be displayed in an output text field
TextEditingController _stringInputController = TextEditingController(); // Allows us to get the text from a text field
TextEditingController _numberInputController = TextEditingController();
@override
Widget build( BuildContext context ) {
return MaterialApp(
debugShowCheckedModeBanner: false, // Disable debug banner in top right
home: Scaffold ( // Scaffold provides a layout for the app
body: Center ( // Everything in the center widget will be centered
child: Column ( // All the widgets will be in a column
children: <Widget> [
SizedBox( height: 25 ), // Space between top and text field
TextField ( // String input Text Field
controller: _stringInputController, // Add input controller so we can grab text
textAlign: TextAlign.center, // Center text
decoration: InputDecoration( border: OutlineInputBorder(), labelText: 'Enter a string...'), // Border and default text
), // end TextField
SizedBox( height: 10 ), // Space between text fields
TextField ( // Number input Text Field
controller: _numberInputController, // Add input controller so we can grab text
textAlign: TextAlign.center, // Center text
decoration: InputDecoration( border: OutlineInputBorder(), labelText: 'Enter 75000'), // Border and default text
), // end TextField
FlatButton ( // Submit Button
child: Text('Submit Data'), // Button Text
color: Colors.blue[400] // button color
onPressed: () { // On pressed Callback for button
setState( () {
output = ''; // Reset output
int number; // Int to store number in
var stringInput = _stringInputController.text ?? ''; // Get the input from the first field, if it is null set it to an empty string
var numberString = _numberInputController.text ?? ''; // Get the input from the second field, if it is null set it to an empty string
if ( stringInput == '') { // If first field is empty
output = 'Please enter something in field 1\n';
return;
}
if (_numberInputController.text == '') { // If second field is empty
output += 'Please enter something in field 2';
return;
} else { // If we got an input in the second field
try {
number = int.parse( numberString ); // Parse numberString into an int
if ( number == 75000 )
output = 'text output: $stringInput\nnumber: $number'; // Grabs the text from the input controllers and changes the string
else
output = '$number is not 75000!';
} on FormatException { // If a number is not entered in second field
output = '$numberString is not a number!';
}
}
});
}
), // End FlatButton
Text( output ) // displays output
]
)
)
)
);
}
}