Implementing Timer and its examples

doc/examples/timer/.gitignore

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+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.buildlog/
+.history
+.svn/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# Visual Studio Code related
+.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+.dart_tool/
+.flutter-plugins
+.packages
+.pub-cache/
+.pub/
+/build/
+
+# Android related
+**/android/**/gradle-wrapper.jar
+**/android/.gradle
+**/android/captures/
+**/android/gradlew
+**/android/gradlew.bat
+**/android/local.properties
+**/android/**/GeneratedPluginRegistrant.java
+
+# iOS/XCode related
+**/ios/**/*.mode1v3
+**/ios/**/*.mode2v3
+**/ios/**/*.moved-aside
+**/ios/**/*.pbxuser
+**/ios/**/*.perspectivev3
+**/ios/**/*sync/
+**/ios/**/.sconsign.dblite
+**/ios/**/.tags*
+**/ios/**/.vagrant/
+**/ios/**/DerivedData/
+**/ios/**/Icon?
+**/ios/**/Pods/
+**/ios/**/.symlinks/
+**/ios/**/profile
+**/ios/**/xcuserdata
+**/ios/.generated/
+**/ios/Flutter/App.framework
+**/ios/Flutter/Flutter.framework
+**/ios/Flutter/Generated.xcconfig
+**/ios/Flutter/app.flx
+**/ios/Flutter/app.zip
+**/ios/Flutter/flutter_assets/
+**/ios/ServiceDefinitions.json
+**/ios/Runner/GeneratedPluginRegistrant.*
+
+# Exceptions to above rules.
+!**/ios/**/default.mode1v3
+!**/ios/**/default.mode2v3
+!**/ios/**/default.pbxuser
+!**/ios/**/default.perspectivev3
+!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages

doc/examples/timer/.metadata

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+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: 0ba67226ee62d6c9d663a6f8410fb4b2f1076046
+  channel: dev
+
+project_type: app

doc/examples/timer/README.md

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+# timer
+
+Flame game showcasing Timer class

doc/examples/timer/lib/main.dart

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+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+import 'package:flame/flame.dart';
+import 'package:flame/game.dart';
+import 'package:flame/time.dart';
+import 'package:flame/text_config.dart';
+import 'package:flame/position.dart';
+
+void main() {
+  final game = MyGame();
+  runApp(game.widget);
+
+  Flame.util.addGestureRecognizer(TapGestureRecognizer()
+    ..onTapDown = (TapDownDetails evt) {
+      game.countdown.start();
+    });
+}
+
+class MyGame extends Game {
+  final TextConfig textConfig = TextConfig(color: const Color(0xFFFFFFFF));
+  Timer countdown;
+  Timer interval;
+
+  int elapsedSecs = 0;
+
+  MyGame() {
+    countdown = Timer(2);
+    interval = Timer(1, repeat: true, callback: () {
+      elapsedSecs += 1;
+    });
+    interval.start();
+  }
+
+  @override
+  void update(double dt) {
+    countdown.update(dt);
+    interval.update(dt);
+  }
+
+  @override
+  void render(Canvas canvas) {
+    textConfig.render(canvas, "Countdown: ${countdown.current.toString()}", Position(10, 100));
+    textConfig.render(canvas, "Elapsed time: $elapsedSecs", Position(10, 150));
+  }
+}

doc/examples/timer/pubspec.yaml

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+name: timer
+description: Example app using Timer class
+
+version: 1.0.0+1
+
+environment:
+  sdk: ">=2.0.0-dev.68.0 <3.0.0"
+
+dependencies:
+  flutter:
+    sdk: flutter
+  flame:
+      path: ../../../
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter

lib/time.dart

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+/// Simple utility class that helps handling time counting and implementing interval like events.
+///
 class Timer {
   final double _limit;
   void Function() _callback;
-  double _current;
+  bool _repeat;
+  double _current = 0;
   bool _running = false;
 
-  Timer(this._limit, this._callback);
+  Timer(this._limit, { repeat = false, callback }) {
+    _repeat = repeat;
+    _callback = callback;
+  }
+
+  double get current {
+    return _current;
+  }
 
   void update(double dt) {
     if (_running) {
       _current += dt;
 
       if (isFinished()) {
+        if (_repeat) {
+          _current -= _limit;
+        } else {
           _running = false;
+        }
+
+        if (_callback != null) {
           _callback();
         }
       }
     }
+  }
 
   bool isFinished() {
     return _current >= _limit;