AppBrewery - Xylophone

Question 1

how to add dependencies

Answer 1

in pubspec.yaml, add under dependencies

Question 2

dependency sytnax

Answer 2

`dependencies:

(optional>)

Question 3

stless widget constructor for widget properties

Answer 3

class KeyNote extends StatelessWidget {
  final Color color;
  final int assetNumber;

  const KeyNote({
    Key key,
    this.color,
    this.assetNumber,
  }) : super (key: key);

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 10.0),
      child: FlatButton(
        color: color,
        onPressed: playNote,
      ),
    );
  }

  void playNote () {
    final player = AudioCache();
    player.play('note$assetNumber.wav');
  }
}

Question 4

named, optional Dart function parameters

Answer 4

A parameter wrapped by [ ] is a positional optional parameter. Here is an example:

getHttpUrl(String server, String path, [int port=80]) {
  // ...
}
A parameter wrapped by { } is a named optional parameter.
foo({@required String name}) {...}

Question 5

on column or row, stretch along main axis for available space

Answer 5

expanded wraps children

Question 6

type dart functions?

Answer 6

if returning, type function of return; int getMilk() { //… return 1}

Question 7

num dart

Answer 7

either int or floating point number type

Question 8

dart fat arrow syntax, equivalent

Answer 8

The ` => expr syntax is a shorthand for { return expr; } `