Jump into cross-platform development with FirebaseDynamic Database, Authentication and much more...

Constantine MarsTeam Lead, Senior Developer @ DataArtOrganizer @ GDG Dnipro-Art

GDGFirst - about this day

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What is a GDG?

Google Developer Groups (GDGs) are for developers who are interested in Google's developer

technology; everything from the Android, App Engine, and Google Chrome platforms, to product APIs

like the Maps API, YouTube API and Google Calendar API.

A GDG can take many forms -- from just a few people getting together to watch our latest video, to

large gatherings with demos and tech talks, to events like code sprints and hackathons. However, at

the core, GDGs are focused on developers and technical content, and the core audience should be

developers.

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A GDG is

● Run by passionate individuals in the developer community

● A place to learn about Google Technologies and Tools for developers.

● A place to see what local companies and developers are doing with these

technologies

● Focused on developers and educational technical content

● Open to the public with a public membership

● A place to meet cool and smart people in tech :)

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A GDG is NOT

● Run by a corporation

● A place to hear a very salesy pitch at any time

● Focused on end users or consumer content

● A closed group

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Worldwide GDG Community

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GDG in Ukraine

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Upcoming Events - GDG DevFest Ukraine

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Upcoming Events - Google I/O

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Upcoming Events - Google Developer Day

FirebaseOverview

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HistorySeptember 2011 - James Tamplin and Andrew Lee

founded Envolve, that provided developers an API

that let them integrate online chat into their

websites

April 2012 - Tamplin and Lee decided to separate

the chat system and the real-time architecture that

powered it, founding Firebase as a separate

company

21 October 2014 - Firebase announced it had been

acquired by Google

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History

February 16, 2016 - David East announced Firecasts

video series for Firebase developers

May 18, 2016 - James Tamplin and Francis Ma

present Firebase Overview on Google I/O ‘16

January 18, 2017 - Google announced that it signed

an agreement to acquire Fabric and Crashlytics from

Twitter, and that those services would join the

Firebase team.

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Overview

Project setupClick-click-boom

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Project setup in console

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Project setup in console

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Project setup in console

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Project setup in console

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Project setup in console

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Android Studio Assistant

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Android Studio Assistant

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Android Studio Assistant

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Android Studio Assistant

AuthenticationBe together, not the same!

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Authentication

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Enable Authentication types

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@Override public void onActivityResult(int requestCode, int resultCode, Intent data) { …

if (requestCode == RC_SIGN_IN) { GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data); if (result.isSuccess()) { // Google Sign In was successful, authenticate with Firebase GoogleSignInAccount account = result.getSignInAccount(); firebaseAuthWithGoogle(account); } else { // Google Sign In failed, update UI appropriately // ... } } }

Authentication (Google Sign In)

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AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null);mAuth.signInWithCredential(credential) .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() { @Override public void onComplete(@NonNull Task<AuthResult> task) { Log.d(TAG, "signInWithCredential:onComplete:" + task.isSuccessful());

// If sign in fails, display a message to the user. If sign in succeeds // the auth state listener will be notified and logic to handle the // signed in user can be handled in the listener. if (!task.isSuccessful()) { Log.w(TAG, "signInWithCredential", task.getException()); Toast.makeText(GoogleSignInActivity.this, "Authentication failed.", Toast.LENGTH_SHORT).show(); } // ... } });

Authentication (Google Sign In)

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FirebaseAuth.getInstance().signOut();

Sign out

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Rules

Firebase Database, pt1Basics

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With FirebaseDatabase

private DatabaseReference mDatabase;

// ...

mDatabase = FirebaseDatabase.getInstance().getReference();

Get Database reference

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public class BatteryStatus { public int level; public int status;

public BatteryStatus() { }

public BatteryStatus(int level, int status) { this.level = level; this.status = status; }}

Use POJOs or primitive types

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With FirebaseDatabase

BatteryStatus batteryStatus = new

BatteryStatus(lastBatteryLevel, lastIsChargingStatus);

mDatabase.child("battery_status").child("current_status").setVal

ue(batteryStatus);

mDatabase.child("voting").setValue(lastVote);

Write values

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Written values visible in console

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mDatabase.child("battery_status").addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { BatteryStatus batteryStatus1 = dataSnapshot.child("current_status").getValue(BatteryStatus.class); lastBatteryLevel = batteryStatus1.level; }

@Override public void onCancelled(DatabaseError databaseError) {

} });

Read values = listen to changes

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private void onPerformTransaction(DatabaseReference postRef) { postRef.runTransaction(new Transaction.Handler() { @Override public Transaction.Result doTransaction(MutableData mutableData) { Voting p = mutableData.getValue(Voting.class); if (p == null) { return Transaction.success(mutableData); }

p.setValue(true); // Set value and report transaction success mutableData.setValue(p); return Transaction.success(mutableData); }

@Override public void onComplete(DatabaseError databaseError, boolean b, DataSnapshot dataSnapshot) { // Transaction completed } });}

Transactions

Firebase Database, pt2How to make queries in NoSQL

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It’s a JSON tree

{ "users": { "droid_ninja": { "name": "Android Ninja", "battery_status": { "74": true }, }, "raspberry_pike": { ... }, "fire_tamplin": { ... } }}

Structure data

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{ // This is a poorly nested data architecture, because iterating the children // of the "chats" node to get a list of conversation titles requires // potentially downloading hundreds of megabytes of messages "chats": { "one": { "title": "Phone battery discussions", "messages": { "m1": { "sender": "droid_ninja", "message": "Looks like Doze Mode doesn’t help" }, "m2": { ... }, // a very long list of messages } }, "two": { ... } }}

Avoid nesting

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// Conversation members are easily accessible // and stored by chat conversation ID "members": { // we'll talk about indices like this below "one": { "droid_ninja": true, "fire_tamplin": true, "raspbery_pike": true }, "two": { ... }, "three": { ... } },

Flatten data structures

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{ // Chats contains only meta info about each conversation // stored under the chats's unique ID "chats": { "one": { "title": "Battery talks", "lastMessage": "ninja: Battery exhausting", "timestamp": 1459361875666 }, "two": { ... }, "three": { ... } },

...

Flatten data structures

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// An index to track Ada's memberships{ "users": { "droid_ninja": { "name": "Droid Ninja", // Index Ada's groups in her profile "groups": { // the value here doesn't matter, just that the key exists "gdg": true, "geeks": true

"foreigners": false } }, ... },

Use an index

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"groups": { "gdg": { "name": "GDG", "members": { "droid_ninja": true, "fire_tamplin": true, "raspberry_pike": true } }, ... }}

Use an index

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firebase.database.Query class

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ChildEventListener childEventListener = new ChildEventListener() { @Override public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) {}

@Override public void onChildChanged(DataSnapshot dataSnapshot, String previousChildName) {}

@Override public void onChildRemoved(DataSnapshot dataSnapshot) {}...};ref.addChildEventListener(childEventListener);

ListsJust push()

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Ordering

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// My top posts by number of starsString myUserId = getUid();Query myTopPostsQuery = databaseReference.child("user-posts").child(myUserId) .orderByChild("starCount");myTopPostsQuery.addChildEventListener(new ChildEventListener() { // TODO: implement the ChildEventListener methods as documented above // ...});

Ordering

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Filtering

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/ Last 100 posts, these are automatically the 100 most recent// due to sorting by push() keysQuery recentPostsQuery = databaseReference.child("posts") .limitToFirst(100);

Limit

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// My top posts by number of starsmyTopPostsQuery.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) { // TODO: handle the post } }

@Override public void onCancelled(DatabaseError databaseError) {}});

Filtering example

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Query biggest value of “weight”

ref

.orderByChild("weight")

.limitToLast(2)

.on("child_added", function(snapshot) {

console.log(snapshot.key());

});

More query examples

And more...There are a lot of tools in the box

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Samples

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And even more...

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Links

● Firebase home: https://firebase.google.com/

● Firebase docs: https://firebase.google.com/docs/

● Firebase blog: https://firebase.googleblog.com/

● Firecasts Youtube Channel: https://goo.gl/9giPHG

● Firecasts for iOS: https://goo.gl/eNioSp

● Firecasts for Android: https://goo.gl/M7UPTv

● Firebase for SQL Developers on Youtube:

https://youtu.be/WacqhiI-g_o?list=PLl-K7zZEsYLlP-k-RKFa7RyNPa9_wCH2s

Constantine Mars@DataArt@ConstantineMars+ConstantineMars

Q&A

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