Complete Firebase Cheatsheet in Flutter

Firebase is a powerful tool for building mobile applications. It provides a variety of features such as authentication, cloud storage, analytics, and more. In this guide, we'll provide a complete cheatsheet for integrating Firebase into your Flutter apps. We'll cover topics such as installing Firebase into your project, authentication, Firestore integration, Firebase storage integration, and analytics integration. We'll provide code snippets and detailed documentation for each section. Let's get started!

Installing Firebase into Your Project

The first step in integrating Firebase into your Flutter project is to install the Firebase package. To do this, open your pubspec.yaml file and add the following line to the dependencies section:

firebase_core: ^0.4.4

Then, run the flutter packages get command in your project's root directory to install the Firebase package.

Authentication with Firebase in Flutter

Firebase provides a powerful authentication system for your Flutter apps. It supports many different authentication methods, such as email/password, phone numbers, and social media account sign-in. We'll cover three of the most common methods: registration, login, and SMS verification.

Registration with Firebase in Flutter

To register a user with Firebase, you'll need to create an instance of the FirebaseAuth class. You can then call the createUserWithEmailAndPassword() method to register a new user with an email address and password. Here's an example:

final FirebaseAuth _auth = FirebaseAuth.instance;

// Register a new user
final AuthResult result = await _auth.createUserWithEmailAndPassword(
  email: '[email protected]',
  password: 'password'
);

Login with Firebase in Flutter

Once a user has been registered, you can use the signInWithEmailAndPassword() method to log them in. Here's an example:

// Log in an existing user
final AuthResult result = await _auth.signInWithEmailAndPassword(
  email: '[email protected]',
  password: 'password'
);

SMS Verification with Firebase in Flutter

You can also use Firebase to verify a user's phone number via SMS. To do this, you'll need to call the verifyPhoneNumber() method, passing in the user's phone number and a PhoneVerificationCompleted callback. Here's an example:

// Verify a user's phone number
await _auth.verifyPhoneNumber(
  phoneNumber: '+11234567890',
  verificationCompleted: (AuthCredential credential) {
    // User is verified
  },
  verificationFailed: (AuthException exception) {
    // Verification failed
  },
);

Resetting Passwords with Firebase in Flutter

You can also use Firebase to reset a user's password. To do this, call the sendPasswordResetEmail() method, passing in the user's email address. Here's an example:

// Send a password reset email
await _auth.sendPasswordResetEmail(email: '[email protected]');

Firestore Integration in Flutter

Firebase also provides a powerful cloud-based NoSQL database called Firestore. You can use Firestore to store and retrieve data from your Flutter apps. We'll cover five common operations: writing data, reading single data, reading lists, pagination, and sorting & filtering.

Writing Data to Firestore in Flutter

To write data to Firestore, you'll need to create an instance of the Firestore class. You can then call the collection() method to get a reference to a collection, and the document() method to get a reference to a document. You can then call the setData() method to write data to the document. Here's an example:

// Create a reference to the Firestore database
final Firestore _db = Firestore.instance;

// Create a reference to a document
final DocumentReference ref = _db.collection('users').document('userId');

// Write data to the document
ref.setData({
  'name': 'John Doe',
  'email': '[email protected]'
});

Reading Single Data from Firestore in Flutter

To read data from Firestore, you can call the get() method to get a single document. Here's an example:

// Get a single document
final DocumentSnapshot doc = await ref.get();

// Read the data from the document
final String name = doc.data['name'];
final String email = doc.data['email'];

Reading Lists from Firestore in Flutter

You can also read a list of documents from Firestore. To do this, call the snapshots() method to get a QuerySnapshot object. You can then iterate over the list of documents to read their data. Here's an example:

// Get a list of documents
final QuerySnapshot docs = await ref.collection('users').snapshots();

// Iterate over the documents
for (DocumentSnapshot doc in docs.documents) {
  final String name = doc.data['name'];
  final String email = doc.data['email'];
}

Pagination with Firestore in Flutter

You can also paginate data from Firestore. To do this, you'll need to call the limit() method to limit the number of documents returned, and the offset() method to skip a certain number of documents. Here's an example:

// Get a list of documents, limited to 10
final QuerySnapshot docs = await ref.collection('users')
  .limit(10)
  .offset(10)
  .snapshots();

Sorting & Filtering with Firestore in Flutter

Firestore also supports sorting and filtering data. To sort data, you can call the orderBy() method, passing in the field you want to sort by. To filter data, you can call the where() method, passing in a field and a value. Here's an example:

// Get a list of documents, sorted by name
final QuerySnapshot docs = await ref.collection('users')
  .orderBy('name')
  .snapshots();

// Get a list of documents, filtered by age
final QuerySnapshot docs = await ref.collection('users')
  .where('age', isEqualTo: 18)
  .snapshots();

Grouping & Aggregating with Firestore in Flutter

You can also group and aggregate data from Firestore. To group data, you can call the groupBy() method, passing in the field you want to group by. To aggregate data, you can call the aggregate() method, passing in an aggregation operator and a field. Here's an example:

// Group data by age
final QuerySnapshot docs = await ref.collection('users')
  .groupBy('age')
  .snapshots();

// Aggregate data by age
final QuerySnapshot docs = await ref.collection('users')
  .aggregate(AggregateType.sum, 'age')
  .snapshots();

Firebase Storage Integration in Flutter

Firebase also provides a powerful cloud storage system. You can use Firebase storage to store and retrieve files from your Flutter apps. To do this, you'll need to create an instance of the FirebaseStorage class. You can then call the ref() method to get a reference to a file, and the putFile() method to upload a file. Here's an example:

// Create a reference to the Firebase Storage
final FirebaseStorage _storage = FirebaseStorage.instance;

// Create a reference to a file
final StorageReference ref = _storage.ref().child('images/example.jpg');

// Upload a file
final StorageUploadTask task = ref.putFile(File('path/to/file.jpg'));

Analytics Integration in Flutter

Firebase also provides powerful analytics tools. You can use Firebase analytics to track user events and get insights into your app's usage. To do this, you'll need to create an instance of the FirebaseAnalytics class. You can then call the logEvent() method to track an event. Here's an example:

// Create a reference to the Firebase Analytics
final FirebaseAnalytics _analytics = FirebaseAnalytics();

// Log an event
_analytics.logEvent(name: 'user_login');

Conclusion

This guide provided a complete cheatsheet for integrating Firebase into your Flutter apps. We covered topics such as installing Firebase into your project, authentication, Firestore integration, Firebase storage integration, and analytics integration. We also provided code snippets and detailed documentation for each section. We hope this guide was helpful!