Add a Material/Cupertino adaptive application example (#69)

platform_design/lib/utils.dart

@@ -0,0 +1,92 @@
+import 'dart:math';
+
+import 'package:english_words/english_words.dart';
+// This reimplements generateWordPair because english_words's
+// implementation has some performance issues.
+// https://github.com/filiph/english_words/issues/9
+// ignore: implementation_imports
+import 'package:english_words/src/words/unsafe.dart';
+import 'package:flutter/material.dart';
+
+// This file has a number of platform-agnostic non-Widget utility functions.
+
+const _myListOfRandomColors = [
+  Colors.red, Colors.blue, Colors.teal, Colors.yellow, Colors.amber,
+  Colors.deepOrange, Colors.green, Colors.indigo, Colors.lime, Colors.pink,
+  Colors.orange,
+];
+
+final _random = Random();
+
+Iterable wordPairIterator = generateWordPair();
+Iterable<WordPair> generateWordPair() sync* {
+  bool filterWord(word) => unsafe.contains(word);
+  String pickRandom(List<String> list) => list[_random.nextInt(list.length)];
+
+  String prefix;
+  while (true) {
+    if (_random.nextBool()) {
+      prefix = pickRandom(adjectives);
+    } else {
+      prefix = pickRandom(nouns);
+    }
+    final suffix = pickRandom(nouns);
+
+    if (filterWord(prefix) || filterWord(suffix))
+      continue;
+
+    final wordPair = WordPair(prefix, suffix);
+    yield wordPair;
+  }
+}
+
+String generateRandomHeadline() {
+  final artist = capitalizePair(wordPairIterator.first);
+
+  switch (_random.nextInt(9)) {
+    case 0:
+      return '$artist says ${nouns[_random.nextInt(nouns.length)]}';
+    case 1:
+      return '$artist arrested due to ${wordPairIterator.first.join(' ')}';
+    case 2:
+      return '$artist releases ${capitalizePair(wordPairIterator.first)}';
+    case 3:
+      return '$artist talks about his ${nouns[_random.nextInt(nouns.length)]}';
+    case 4:
+      return '$artist talks about her ${nouns[_random.nextInt(nouns.length)]}';
+    case 5:
+      return '$artist talks about their ${nouns[_random.nextInt(nouns.length)]}';
+    case 6:
+      return '$artist says their music is inspired by ${wordPairIterator.first.join(' ')}';
+    case 7:
+      return '$artist says the world needs more ${nouns[_random.nextInt(nouns.length)]}';
+    case 7:
+      return '$artist calls their band ${adjectives[_random.nextInt(adjectives.length)]}';
+    case 8:
+      return '$artist finally ready to talk about ${nouns[_random.nextInt(nouns.length)]}';
+  }
+
+  assert(false, 'Failed to generate news headline');
+  return null;
+}
+
+List<MaterialColor> getRandomColors(int amount) {
+  return List<MaterialColor>.generate(amount, (int index) {
+    return _myListOfRandomColors[_random.nextInt(_myListOfRandomColors.length)];
+  });
+}
+
+List<String> getRandomNames(int amount) {
+  return wordPairIterator
+      .take(amount)
+      .map((pair) => capitalizePair(pair))
+      .toList();
+}
+
+String capitalize(String word) {
+  return '${word[0].toUpperCase()}${word.substring(1).toLowerCase()}';
+}
+
+String capitalizePair(WordPair pair) {
+  return '${capitalize(pair.first)} ${capitalize(pair.second)}';
+}