Firebase with Android

1. Firebase with
Android
GCPUG TOKYO MARCH 2016

2. Firebase

3. Firebase
• Realtime Database
• Authentication & Access Control
• Static Web Site Hosting

4. Udacity
• Firebase Essential For Android
• https://www.udacity.com/course/firebase-
essentials-for-android--ud009

5. Getting Started

6. www.firebase.com

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

11. android {
...
packagingOptions {
exclude 'META-INF/LICENSE'
exclude 'META-INF/LICENSE-FIREBASE.txt'
exclude 'META-INF/NOTICE'
}
}

12. <uses-permission android:name="android.permission.INTERNET" />

13. Custom Application
public class MyApplication extends Application {
@Override
public void onCreate() {
super.onCreate();
Firebase.setAndroidContext(this);
}
}

14. AndroidManifest.xml
<application
android:name=".MyApplication"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">

15. Writing Data

16. AndroidManifest.xml
Firebase firebaseRef = new Firebase("https://shiroyama-app-01.firebaseio.com/");
firebaseRef.child("message").setValue("hello firebase!");

17. Activity
Firebase firebaseRef = new Firebase("https://shiroyama-app-01.firebaseio.com/");
firebaseRef.child("message").setValue("hello firebase!");
Reference

18. Activity
Firebase firebaseRef = new Firebase("https://shiroyama-app-01.firebaseio.com/");
firebaseRef.child("message").setValue("hello firebase!");
Child Node

19. Activity
Firebase firebaseRef = new Firebase("https://shiroyama-app-01.firebaseio.com/");
firebaseRef.child("message").setValue("hello firebase!");
Writing

21. Not Limited to
Primitive Types

22. 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;
}
}

23. Understating
Data Structure

24. NoSQL JSON Tree
{
"users": {
"mchen": {
"friends": { "brinchen": true },
"name": "Mary Chen",
// our child node appears in the existing JSON tree
"widgets": { "one": true, "three": true }
},
"brinchen": { ... },
"hmadi": { ... }
}
}

25. NoSQL JSON Tree
{
"users": {
"mchen": {
"friends": { "brinchen": true },
"name": "Mary Chen",
// our child node appears in the existing JSON tree
"widgets": { "one": true, "three": true }
},
"brinchen": { ... },
"hmadi": { ... }
}
}

26. NoSQL JSON Tree
{
"users": {
"mchen": {
"friends": { "brinchen": true },
"name": "Mary Chen",
// our child node appears in the existing JSON tree
"widgets": { "one": true, "three": true }
},
"brinchen": { ... },
"hmadi": { ... }
}
}
/users/mchen/widgets

27. NoSQL JSON Tree
{
"users": {
"mchen": {
"friends": { "brinchen": true },
"name": "Mary Chen",
// our child node appears in the existing JSON tree
"widgets": { "one": true, "three": true }
},
"brinchen": { ... },
"hmadi": { ... }
}
}
/users/mchen/widgets
Unique Identifier

28. Valid Types

29. • String
• Boolean
• Long
• Double
• Map<String, Object>
• List<Object>

30. Retrieving Data

31. Firebase firebaseRef = new Firebase("https://shiroyama-app-01.firebaseio.com/");
firebaseRef.child("message").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Toast.makeText(
MainActivity.this,
dataSnapshot.getValue(String.class),
Toast.LENGTH_SHORT
).show();
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});

32. Firebase firebaseRef = new Firebase("https://shiroyama-app-01.firebaseio.com/");
firebaseRef.child("message").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Toast.makeText(
MainActivity.this,
dataSnapshot.getValue(String.class),
Toast.LENGTH_SHORT
).show();
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});

33. Firebase firebaseRef = new Firebase("https://shiroyama-app-01.firebaseio.com/");
firebaseRef.child("message").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Toast.makeText(
MainActivity.this,
dataSnapshot.getValue(String.class),
Toast.LENGTH_SHORT
).show();
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});

34. Firebase firebaseRef = new Firebase("https://shiroyama-app-01.firebaseio.com/");
firebaseRef.child("message").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Toast.makeText(
MainActivity.this,
dataSnapshot.getValue(String.class),
Toast.LENGTH_SHORT
).show();
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});

35. Firebase firebaseRef = new Firebase("https://shiroyama-app-01.firebaseio.com/");
firebaseRef.child("message").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Toast.makeText(
MainActivity.this,
dataSnapshot.getValue(String.class),
Toast.LENGTH_SHORT
).show();
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});

36. Read Event Types

37. • Value
• Child Added
• Child Changed
• Child Removed
• Child Moved

38. Value Event
• ValueEventListener#onDataChange
• Retrieve whole data at once
• Called once at initial time, then every time
data changes.

39. // Get a reference to our posts
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());
}
});

40. // Get a reference to our posts
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());
}
});

41. // Get a reference to our posts
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());
}
});

42. Child Added Event
• ChildEventListener#onChildAdded
• Once for each existing child initially
• Every time new data is added

43. // Get a reference to our posts
Firebase ref = new Firebase("https://docs-examples.firebaseio.com/web/saving-data/fireblog/posts");
ref.addChildEventListener(new ChildEventListener() {
// Retrieve new posts as they are added to the database
@Override
public void onChildAdded(DataSnapshot snapshot, String previousChildKey) {
BlogPost newPost = snapshot.getValue(BlogPost.class);
System.out.println("Author: " + newPost.getAuthor());
System.out.println("Title: " + newPost.getTitle());
}
//... ChildEventListener also defines onChildChanged, onChildRemoved,
// onChildMoved and onCanceled, covered in later sections.
});

44. Child Changed Event
• ChildEventListener#onChildChanged
• Anytime a child is changed including its
descendants

45. @Override
public void onChildChanged(DataSnapshot snapshot, String previousChildKey) {
String title = (String) snapshot.child("title").getValue();
System.out.println("The updated post title is " + title);
}

46. Child Removed Event
• ChildEventListener#onChildRemoved
• Anytime a child is removed

47. @Override
public void onChildRemoved(DataSnapshot snapshot) {
String title = (String) snapshot.child("title").getValue();
System.out.println("The blog post titled " + title + " has been deleted");
}

48. Child Moved Event
• ChildEventListener#onChildMoved
• Anytime a child is moved

49. @Override
public void onChildMoved(DataSnapshot snapshot, String previousChildKey) {
String title = (String) snapshot.child("title").getValue();
System.out.println("The updated post title is " + title);
}

50. Detaching Callbacks
• ref.removeEventListener(originalListener);
• all listeners must be removed explicitly
• removing parent listener will NOT remove
child's listeners

51. Reading Data Once

52. ref.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot snapshot) {
// do some stuff once
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});

53. ref.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot snapshot) {
// do some stuff once
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});

54. Querying Data

55. {
"lambeosaurus": {
"height" : 2.1,
"length" : 12.5,
"weight": 5000
},
"stegosaurus": {
"height" : 4,
"length" : 9,
"weight" : 2500
}
}

56. public class DinosaurFacts {
long height;
double length;
long weight;
public DinosaurFacts() {
// empty default constructor
// necessary for Firebase to be able to deserialize blog posts
}
public long getHeight() {
return height;
}
public double getLength() {
return length;
}
public long getWeight() {
return weight;
}
}

57. • orderByChild()
• orderByKey()
• orderByValue()
• orderByPriority()

58. orderByChild
Query queryRef = ref.orderByChild("height");
or
Query queryRef = ref.orderByChild("dimensions/height");

59. orderByKey
Query queryRef = ref.orderByKey();
{
"lambeosaurus": {
"height" : 2.1,
"length" : 12.5,
"weight": 5000
},
"stegosaurus": {
"height" : 4,
"length" : 9,
"weight" : 2500
}
}

60. orderByValue
Query queryRef = ref.orderByValue();
{
"scores": {
"bruhathkayosaurus" : 55,
"lambeosaurus" : 21,
"linhenykus" : 80,
"pterodactyl" : 93,
"stegosaurus" : 5,
"triceratops" : 22
}
}

61. orderByPriority
Query queryRef = ref.orderByPriority();

62. orderByPriority
Query queryRef = ref.orderByPriority();
arbitrary priority you set

63. • limitToFirst()
• limitToLast()
• startAt()
• endAt()
• equalTo()

64. Query queryRef = ref.orderByChild("height").limitToFirst(2);
Query queryRef = scoresRef.orderByValue().limitToLast(3);
Query queryRef = ref.orderByChild("height").startAt(3);
Query queryRef = ref.orderByKey().endAt("pterodactyl");
Query queryRef = ref.orderByChild("height").equalTo(25);

65. Security

67. {
"rules": {
"users": {
"$user_id": {
".write": "$user_id === auth.uid"
}
}
}
}

68. {
"rules": {
"users": {
"$user_id": {
".write": "$user_id === auth.uid"
}
}
}
}

69. {
"rules": {
"users": {
"$user_id": {
".write": "$user_id === auth.uid"
}
}
}
} talks about this later

70. Authentication

71. Custom

72. • helper libraries to integrate with your own
authentications
• https://www.firebase.com/docs/android/
guide/login/custom.html#section-rest-token-
helper-libraries

73. Firebase ref = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com/");
ref.authWithCustomToken(AUTH_TOKEN, new Firebase.AuthResultHandler() {
@Override
public void onAuthenticationError(FirebaseError error) {
System.err.println("Login Failed! " + error.getMessage());
}
@Override
public void onAuthenticated(AuthData authData) {
System.out.println("Login Succeeded!");
}
});

74. Firebase ref = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com/");
ref.authWithCustomToken(AUTH_TOKEN, new Firebase.AuthResultHandler() {
@Override
public void onAuthenticationError(FirebaseError error) {
System.err.println("Login Failed! " + error.getMessage());
}
@Override
public void onAuthenticated(AuthData authData) {
System.out.println("Login Succeeded!");
}
});

75. Firebase ref = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com/");
ref.authWithCustomToken(AUTH_TOKEN, new Firebase.AuthResultHandler() {
@Override
public void onAuthenticationError(FirebaseError error) {
System.err.println("Login Failed! " + error.getMessage());
}
@Override
public void onAuthenticated(AuthData authData) {
System.out.println("Login Succeeded!");
}
});
given from your server

76. Firebase ref = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com/");
ref.authWithCustomToken(AUTH_TOKEN, new Firebase.AuthResultHandler() {
@Override
public void onAuthenticationError(FirebaseError error) {
System.err.println("Login Failed! " + error.getMessage());
}
@Override
public void onAuthenticated(AuthData authData) {
System.out.println("Login Succeeded!");
}
});

77. • javadoc
• https://www.firebase.com/docs/java-api/
javadoc/com/firebase/client/AuthData.html
• AuthData#getUid()
Unique Guaranteed

78. Tips

79. • SwipeRefresh should be used with
ValueEvent(once)

80. Limitations

81. • No File Uploading APIs
• Server side batching
• Server side scheduling
• Server side event hook

82. Q & A

83. Samples

84. • Chat
• https://github.com/firebase/AndroidChat
• Drawing
• https://github.com/firebase/AndroidDrawing

85. THX!