add event_bus test

lib/eventBusTest.dart

+import 'dart:async';
+import 'dart:html';
+import 'package:event_bus/event_bus.dart';
+import 'package:flutter/material.dart';
+import 'package:logging/logging.dart';
+
+// import 'events.dart';
+
+int counterA = 1;
+int counterB = 1;
+
+final _log = new Logger('event_bus_example');
+
+void main() {
+  // Init logging.
+  initLogging();
+
+  // Log all events.
+  eventBus
+      .on()
+      .listen((event) => _log.finest('event fired:  ${event.runtimeType}'));
+
+  // Initialize the listener boxes.
+  new Listener(querySelector('#listener-1'));
+  new Listener(querySelector('#listener-2'));
+
+  // Init Event fields.
+  LabelElement fireLabelA = querySelector('#fire-label-a');
+  LabelElement fireLabelB = querySelector('#fire-label-b');
+  ButtonElement fireButtonA = querySelector("#fire-button-a");
+  ButtonElement fireButtonB = querySelector("#fire-button-b");
+
+  fireButtonA.onClick.listen((_) {
+    // -------------------------------------------------
+    // Fire Event A
+    // -------------------------------------------------
+    eventBus.fire(new MyEventA('Received Event A [$counterA]'));
+    fireLabelA.text = '--> fired [$counterA]';
+    counterA++;
+  });
+  fireButtonB.onClick.listen((_) {
+    // -------------------------------------------------
+    // Fire Event B
+    // -------------------------------------------------
+    eventBus.fire(new MyEventB('Received Event B [$counterB]'));
+    fireLabelB.text = '--> fired [$counterB]';
+    counterB++;
+  });
+}
+
+initLogging() {
+  // Print output to console.
+  Logger.root.onRecord.listen((LogRecord r) {
+    print('${r.time}\t${r.loggerName}\t[${r.level.name}]:\t${r.message}');
+  });
+
+  // Root logger level.
+  Logger.root.level = Level.FINEST;
+}
+
+class Listener {
+  Element element;
+
+  TextAreaElement output;
+
+  StreamSubscription subscription;
+
+  Listener(this.element) {
+    output = element.querySelector('textarea');
+    // Init buttons.
+    element.querySelector('.listen-a').onClick.listen((_) => listenForEventA());
+    element.querySelector('.listen-b').onClick.listen((_) => listenForEventB());
+    element.querySelector('.pause').onClick.listen((_) => pause());
+    element.querySelector('.resume').onClick.listen((_) => resume());
+    element.querySelector('.cancel').onClick.listen((_) => cancel());
+  }
+
+  void listenForEventA() {
+    if (subscription != null) {
+      appendOuput('Already listening for an event.');
+    } else {
+      // -------------------------------------------------
+      // Listen for Event A
+      // -------------------------------------------------
+      subscription = eventBus.on<MyEventA>().listen((event) {
+        appendOuput(event.text);
+      });
+      appendOuput('---');
+      appendOuput('Listening for Event A');
+      appendOuput('---');
+    }
+  }
+
+  void listenForEventB() {
+    if (subscription != null) {
+      appendOuput('Already listening for an event.');
+    } else {
+      // -------------------------------------------------
+      // Listen for Event B
+      // -------------------------------------------------
+      subscription = eventBus.on<MyEventB>().listen((MyEventB event) {
+        appendOuput(event.text);
+      });
+      appendOuput('---');
+      appendOuput('Listening for Event B');
+      appendOuput('---');
+    }
+  }
+
+  void pause() {
+    if (subscription != null) {
+      subscription.pause();
+      appendOuput('Subscription paused.');
+    } else {
+      appendOuput('No subscription, cannot pause!');
+    }
+  }
+
+  void resume() {
+    if (subscription != null) {
+      subscription.resume();
+      appendOuput('Subscription resumed.');
+    } else {
+      appendOuput('No subscription, cannot resume!');
+    }
+  }
+
+  void cancel() {
+    if (subscription != null) {
+      subscription.cancel();
+      subscription = null;
+      appendOuput('Subscription canceled.');
+    } else {
+      appendOuput('No subscription, cannot cancel!');
+    }
+  }
+
+  void appendOuput(String text) {
+    output.value += '$text\n';
+    output.scrollTop = output.scrollHeight;
+  }
+}
\ No newline at end of file