Google I/O Android App
Google I/O is a developer conference held each year with three days of deep
technical content featuring technical sessions and hundreds of demonstrations
from developers showcasing their technologies.
This project is the Android app for the conference.
For a simpler fork of the app, check out the Android Dev Summit App in the adssched branch. In this variant some features are removed, such as reservations and the map screen, and Instant App support is added.
Features
The app displays a list of conference events - sessions, office hours, app
reviews, codelabs, etc. - and allows the user to filter these events by event
types and by topics (Android, Firebase, etc.). Users can see details about
events, and they can star events that interest them. Conference attendees can
reserve events to guarantee a seat.
Other features include a Map of the venue, informational pages to
guide attendees during the conference in Info, and time-relevant information
during the conference in Home.
Development Environment
The app is written entirely in Kotlin and uses the Gradle build system.
To build the app, use the gradlew build command or use "Import Project" in
Android Studio. A canary or stable version >= 3.4 of Android Studio is
required and may be downloaded
here.
Architecture
The 2019 version of the app is built on top of the last year's app. The
architecture is built around
Android Architecture Components.
We followed the recommendations laid out in the
Guide to App Architecture
when deciding on the architecture for the app. We kept logic away from
Activities and Fragments and moved it to
ViewModels.
We observed data using
LiveData
and used the Data Binding Library
to bind UI components in layouts to the app's data sources.
We used a Repository layer for handling data operations. IOSched's data comes
from a few different sources - user data is stored in
Cloud Firestore
(either remotely or in
a local cache for offline use), user preferences and settings are stored in
SharedPreferences, conference data is stored remotely and is fetched and stored
in memory for the app to use, etc. - and the repository modules
are responsible for handling all data operations and abstracting the data sources
from the rest of the app (we liked using Firestore, but if we wanted to swap it
out for a different data source in the future, our architecture allows us to do
so in a clean way).
We implemented a lightweight domain layer, which sits between the data layer
and the presentation layer, and handles discrete pieces of business logic off
the UI thread. See the .\*UseCase.kt files under shared/domain for
examples.
We used Navigation component
to simplify into a single Activity app.
We used Room
for Full Text Search using Fts4
to search for a session, speaker, or codelab.
We used Dagger2 for dependency injection
and we heavily relied on
dagger-android to abstract away
boiler-plate code.
We used Espresso
for basic instrumentation tests and JUnit and
Mockito for unit testing.
Firebase
The app makes considerable use of the following Firebase components:
- Cloud Firestore is our source
for all user data (events starred or reserved by a user). Firestore gave us
automatic sync and also seamlessly managed offline functionality
for us. - Firebase Cloud Functions
allowed us to run backend code. The reservations feature heavily depended on Cloud
Functions working in conjuction with Firestore. - Firebase Cloud Messaging
let us inform the app about changes to conference data on our server. - Remote Config helped us
manage in-app constants.
Kotlin
We made an early decision to rewrite the app from scratch to bring it in line
with our thinking about modern Android architecture. Using Kotlin for the
rewrite was an easy choice: we liked Kotlin's expressive, concise, and
powerful syntax; we found that Kotlin's support for safety features for
nullability and immutability made our code more resilient; and we leveraged the
enhanced functionality provided by
Android Ktx extensions.
Copyright
Copyright 2014 Google Inc. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.