Firebase Essentials For Android ¬ GDG WonderCoders, May 2016 

Erik Jhordan González Reyes Android developer "Strong believer in software craftsmanship, SOLID, clean code and testing." 

Talk Schedule ● Firebase Guide for android ● Android + Firebase Sample ● Answers & Questions 

Installation & Setup 

dependencies { compile 'com.firebase:firebase-client-android:2.5.2+' } Firebase 

Firebase android { ... packagingOptions { exclude 'META-INF/LICENSE' exclude 'META-INF/LICENSE-FIREBASE.txt' exclude 'META-INF/NOTICE' } } If you are getting a build error complaining about duplicate files you can choose to exclude those files. 

Firebase Add Internet Permission 

@Override public void onCreate() { super.onCreate(); Firebase.setAndroidContext(this); // other setup code } Firebase setup firebase on android 

Understanding Data Firebase 

Firebase All Firebase database data is stored as JSON objects. { "users": { "mchen": { "friends": { "brinchen": true }, "name": "Mary Chen", // our child node appears in the existing JSON tree "widgets": { "one": true, "three": true } }, "brinchen": { ... }, "hmadi": { ... } } } 

Firebase These types correspond to the types available in JSON. ●String ●Boolean ●Long ●Double ●Map ●List 

Firebase Creating a Firebase database Reference Firebase rootRef = new Firebase("https://docs-examples.firebaseio.com/web/data"); 

Saving Data Firebase 

Firebase Ways to Save Data four methods for writing data to the Firebase database. ● setValue() ● updateChildren() ● push() ● runTransaction() 

Firebase setValue() Saves data to the specified Firebase reference, replacing any existing data at that path. Example -Firebase Reference -Object -save data using setValue() 

Firebase Firebase ref = new Firebase("https://docs-examples.firebaseio.com/android/saving-data/fireblog"); Firebase Reference 

Firebase public class User { private int birthYear; private String fullName; public User() {} public User(String fullName, int birthYear) { this.fullName = fullName; this.birthYear = birthYear; } public long getBirthYear() { return birthYear; } public String getFullName() { return fullName; } } Creating an Object 

Firebase Firebase alanRef = ref.child("users").child("alanisawesome"); User alan = new User("Alan Turing", 1912); alanRef.setValue(alan); Saving Data 

Firebase { "users": { "alanisawesome": { "birthYear": "1912", "fullName": "Alan Turing" } } } Result 

Firebase updateChildren() If you want to write to specific children of a node at the same time without overwriting other child nodes. Firebase alanRef = usersRef.child("alanisawesome"); Map nickname = new HashMap(); nickname.put("nickname", "Alan The Machine"); alanRef.updateChildren(nickname); 

Firebase Result { "users": { "alanisawesome": { "birthYear": "1912", "fullName": "Alan Turing", "nickname": "Alan The Machine", } } } 

Firebase Using multi-path updates updateChildren() can now update values at multiple locations in your Firebase database at the same time. Map nicknames = new HashMap(); nickname.put("alanisawesome/nickname", "Alan The Machine"); nickname.put("gracehop/nickname", "Amazing Grace"); usersRef.updateChildren(nicknames); 

Firebase Result "users": { "alanisawesome": { "date_of_birth": "June 23, 1912", "full_name": "Alan Turing", "nickname": "Alan The Machine" }, "gracehop": { "date_of_birth": "December 9, 1906", "full_name": "Grace Hopper", "nickname": "Amazing Grace" } } } 

Firebase Adding a Completion Callback ref.setValue("I'm writing data", new Firebase.CompletionListener() { @Override public void onComplete(FirebaseError firebaseError, Firebase firebase) { if (firebaseError != null) { System.out.println("Data could not be saved. " + firebaseError. getMessage()); } else { System.out.println("Data saved successfully."); } } }); 

Firebase push() Generates a unique ID every time a new child is added to the specified Firebase reference. Firebase postRef = ref.child("posts"); Map post1 = new HashMap(); post1.put("author", "gracehop"); post1.put("title", "Announcing COBOL, a New Programming Language"); postRef.push().setValue(post1); Map post2 = new HashMap(); post2.put("author", "alanisawesome"); post2.put("title", "The Turing Machine"); postRef.push().setValue(post2); 

Firebase Result { "posts": { "-JRHTHaIs-jNPLXOQivY": { "author": "gracehop", "title": "Announcing COBOL,Programming Language" }, "-JRHTHaKuITFIhnj02kE": { "author": "alanisawesome", "title": "The Turing Machine" } } } 

Retrieving Data Firebase 

Firebase Firebase ref = new Firebase("https://docs-examples.firebaseio.com/web/saving-data/fireblog/posts"); // Attach an listener to read the data at our posts reference ref.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot snapshot) { System.out.println(snapshot.getValue()); } @Override public void onCancelled(FirebaseError firebaseError) { System.out.println("The read failed: " + firebaseError.getMessage()); } }); 

Firebase Read event types public class BlogPost { private String author; private String title; public BlogPost() { // empty default constructor, necessary for Firebase to be able to deserialize blog posts } public String getAuthor() { return author; } public String getTitle() { return title; } } 

Firebase Firebase ref = new Firebase("https://docs-examples.firebaseio.com/web/saving-data/fireblog/posts"); // Attach an listener to read the data at our posts reference ref.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot snapshot) { System.out.println("There are " + snapshot.getChildrenCount() + " blog posts"); for (DataSnapshot postSnapshot: snapshot.getChildren()) { BlogPost post = postSnapshot.getValue(BlogPost.class); System.out.println(post.getAuthor() + " - " + post.getTitle()); } } @Override public void onCancelled(FirebaseError firebaseError) { System.out.println("The read failed: " + firebaseError.getMessage()); } }); 

Structuring Data Firebase 

Firebase Because we can nest data up to 32 levels deep, it's tempting to think that this should be the default structure. However, when we fetch data at a location in our database, we also retrieve all of its child nodes. Therefore, nesting data must be done with careful consideration for how the data will be read later. Use Nested Data Sparingly 

Understanding Security Firebase 

Firebase ● Authentication ● Authorization ● Data Validation Overview 

User Authentication Firebase 

Firebase Firebase makes authentication easy. It can integrate with your existing login server, or authenticate users with only client-side code. It has built-in functionality for email & password, and third-party providers such as Facebook, Twitter, GitHub, and Google. Authentication 

Offline Capabilities Firebase 

Firebase Firebase apps automatically handle temporary network interruptions for you. Cached data will still be available while offline and your writes will be resent when network connectivity is recovered. Enabling disk persistence allows our app to also keep all of its state even after an app restart. We can enable disk persistence with just one line of code. Firebase.getDefaultConfig().setPersistenceEnabled(true); Disk Persistence 

Firebase Tools Firebase 

Firebase ● FirebaseUI (UI Bindings) https://github.com/firebase/firebaseui-android ● GeoFire (Geo Location) https://github.com/firebase/geofire-java Libraries 

Firebase ● Office Mover https://github.com/firebase/office-mover-5000 ● Chat https://github.com/firebase/AndroidChat ● Drawing https://github.com/firebase/AndroidDrawing ● SF Vehicles https://github.com/firebase/geofire-java/tree/master/examples/SFVehicles ● Login Demo https://github.com/firebase/firebase-login-demo-android Examples 

#Show me code Firebase 

Firebase https://github.com/erikcaffrey/Firebase-chat 

Answers & Questions 

Further Reading ● My Personal Blog https://erikcaffrey.github.io ● Firebase Documentation https://www.firebase.com/docs/android/ ● Udacity - Firebase Essentials For Android https://www.udacity.com/course/firebase-essentials-for-android--ud009 ● Github - Firebase https://github.com/firebase 

Erik Jhordan González Reyes Android Developer +Erik Jhordan Rey Caffrey @ErikJhordan_Rey erikcaffrey erikcaffrey.github.io 

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