A Complete Guide - Xamarin Forms Firebase database and api

For iOS:

Install-Package Xam.Firebase.iOS.Auth
Install-Package Xam.Firebase.iOS.Database

For the .NET Standard library (or whichever project contains your shared code):

Install-Package Newtonsoft.Json
Install-Package Xamarin.Essentials

Step 3: Configure Firebase in Android and iOS Projects

For Android:

1. Ensure that google-services.json is placed at the root (not in a folder) of your Android project.
2. In the properties of google-services.json, set the Build Action to GoogleServicesJson.

For iOS:

1. Ensure that GoogleService-Info.plist is placed at the root (not in a folder) of your iOS project.
2. In the properties of GoogleService-Info.plist, set the Build Action to BundleResource.

Step 4: Modify MainActivity.cs and AppDelegate.cs

For Android (MainActivity.cs):

using Android.App;
using Android.Content.PM;
using Android.OS; namespace YourAppNamespace.Droid
{ [Activity(Label = "Your App Name", Icon = "@mipmap/icon", Theme = "@style/MainTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)] public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity { protected override void OnCreate(Bundle savedInstanceState) { TabLayoutResource = Resource.Layout.Tabbar; ToolbarResource = Resource.Layout.Toolbar; base.OnCreate(savedInstanceState); global::Xamarin.Forms.Forms.Init(this, savedInstanceState); LoadApplication(new App()); } }
}

For iOS (AppDelegate.cs):

using Foundation;
using UIKit; namespace YourAppNamespace.iOS
{ [Register("AppDelegate")] public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate { public override bool FinishedLaunching(UIApplication app, NSDictionary options) { global::Xamarin.Forms.Forms.Init(); LoadApplication(new App()); return base.FinishedLaunching(app, options); } }
}

Step 5: Create a Data Model

In your shared code, create a simple data model to represent what you'll be storing in Firebase.

public class User
{ public string Id { get; set; } public string Name { get; set; } public string Email { get; set; } // Default constructor required for deserialization when using JsonSerializer public User() { } public User(string id, string name, string email) { Id = id; Name = name; Email = email; }
}

Step 6: Write Code to Interact with Firebase Database

Create a service to interact with Firebase.

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Firebase.Database;
using YourAppNamespace.Models;
using Newtonsoft.Json; namespace YourAppNamespace.Services
{ public class FirebaseService { private readonly DatabaseReference _databaseReference; public FirebaseService() { var firebaseApp = Firebase.Database.FirebaseDatabase.Instance.Reference; _databaseReference = firebaseApp.Child("Users"); } public async Task<List<User>> GetAllUsersAsync() { var userDataList = new List<User>(); try { var snapshot = await _databaseReference.GetValueAsync(); foreach (var item in snapshot.Children) { var user = JsonConvert.DeserializeObject<User>(item.GetRawJsonValue()); userDataList.Add(user); } } catch (Exception e) { Console.WriteLine($"Error getting users from database: {e.Message}"); } return userDataList; } public async Task AddUserAsync(User user) { try { // Create a new child entry with an auto-generated ID. var newUserRef = _databaseReference.Push(); await newUserRef.SetValueAsync(JsonConvert.SerializeObject(user)); } catch (Exception e) { Console.WriteLine($"Error adding user to database: {e.Message}"); } } public async Task UpdateUserAsync(string userId, User updatedUser) { try { await _databaseReference.Child(userId).SetValueAsync( JsonConvert.SerializeObject(updatedUser)); } catch (Exception e) { Console.WriteLine($"Error updating user in database: {e.Message}"); } } public async Task DeleteUserAsync(string userId) { try { await _databaseReference.Child(userId).RemoveValueAsync(); } catch (Exception e) { Console.WriteLine($"Error deleting user from database: {e.Message}"); } } }
}

Step 7: Use FirebaseService in Your MainPage.xaml.cs

using System.Collections.ObjectModel;
using Xamarin.Forms;
using YourAppNamespace.Models;
using YourAppNamespace.Services; namespace YourAppNamespace.Views
{ public partial class MainPage : ContentPage { private FirebaseService _firebaseService; public ObservableCollection<User> Users { get; set; } public MainPage() { InitializeComponent(); BindingContext = this; Users = new ObservableCollection<User>(); _firebaseService = new FirebaseService(); LoadData(); } private async void LoadData() { var dataList = await _firebaseService.GetAllUsersAsync(); Users.Clear(); foreach (var item in dataList) Users.Add(item); } private async void OnAddUserClicked(object sender, EventArgs e) { var newUser = new User(Guid.NewGuid().ToString(), "John Doe", "john.doe@example.com"); await _firebaseService.AddUserAsync(newUser); LoadData(); } private async void OnUpdateUserClicked(object sender, EventArgs e) { await _firebaseService.UpdateUserAsync("USER_ID", new User("USER_ID", "Jane Doe", "jane.doe@example.com")); LoadData(); } private async void OnDeleteUserClicked(object sender, EventArgs e) { await _firebaseService.DeleteUserAsync("USER_ID"); LoadData(); } }
}

Step 8: Define UI Components in MainPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns=" xmlns:x=" x:Class="YourAppNamespace.Views.MainPage" Title="Users"> <StackLayout> <ListView ItemsSource="{Binding Users}" HasUnevenRows="true"> <ListView.ItemTemplate> <DataTemplate> <TextCell Text="{Binding Name}" Detail="{Binding Email}" /> </DataTemplate> </ListView.ItemTemplate> </ListView> <Button Text="Add User" Clicked="OnAddUserClicked" /> <Button Text="Update User" Clicked="OnUpdateUserClicked" /> <Button Text="Delete User" Clicked="OnDeleteUserClicked" /> </StackLayout>
</ContentPage>

Step 9: Test the Application

1. Set the Android/iOS project as your startup project.
2. Run the application on an emulator or connected device.
3. Test the different buttons:
   • The "Add User" button should insert a new user into the Firebase Database.
   • The "Update User" button should update the user details based on the specified USER_ID.
   • The "Delete User" button should remove a user based on the specified USER_ID.

By following these steps, you can create a simple Xamarin.Forms application that interacts with Firebase Database to perform CRUD (Create, Read, Update, Delete) operations. Always remember to replace "USER_ID" with an actual user identifier from your database to test update and delete functionalities effectively.

Additional Tips

• Security Rules: Don't forget to configure the security rules in your Firebase project to allow public read/write or restrict access based on user authentication.
• Error Handling: Implement better error handling, logging, and user-feedback mechanisms for production apps.
• Dependencies Injection: Consider using Dependency Injection frameworks like Microsoft.Extensions.DependencyInjection to manage services more cleanly.