Firebase Firestore Android Tutorial- retrieve list data

Firebase Firestore :

Firebase firestore is used to store our data in this blog and retrieve it as a form of list.Firebase firestore is a better option when you try to store or retrieve data maintaining high security standards by google.

Not only security there is scalability, flexibility in handling data most importantly its a cloud platform providing ease of access for everyone.

There are better practices involved in storage of data and usage using realtime listeners which make your app highly flexible and async this is what makes your app user friendly.

And regarding maintenance and cost this is the better option for most of the developers who want to maintain quality and offer seamless integration.

Let’s get started

Dependency’s

You need to integrate firebase into your project i have provided a detailed blog on firebase integration

Also make sure you are providing latest dependency’s if you are manually adding them to your project, we have added these 2 dependency’s and remaining are available by default.

implementation 'androidx.cardview:cardview:1.0.0' 
implementation 'com.google.firebase:firebase-firestore-ktx:21.4.3'

Firebase Firestore Video Tutorial :

Go through the below tutorial for more details on firestore implementation.

Project Structure :

The screen below depicts the project structure of firebase firestore

In this project i want to make you understand the usage of firestore easily so i am making it as simple as possible.In coming tutorials with this knowledge we can make complex projects.

activity_main.xml :

We need to add two button one for writing the data and other for reading the data.

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="50dp"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_write_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="28dp"
        android:layout_marginLeft="28dp"
        android:text="Write Data"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btn_read_data"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Read Data"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.546"
        app:layout_constraintStart_toEndOf="@+id/btn_write_data"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity :

Initialize the firestore object

val db = Firebase.firestore

Initialize the buttons we are using kotlin synthetic binding here

btn_write_data.setOnClickListener(this) 
btn_read_data.setOnClickListener(this)

writeData :

Add data in firebase firestore, using add a listener to know the status of adding data we have used hashMap to store data and push it to firebase.

Create a collection named “users”

val user = hashMapOf(
    "id" to 2,
    "Abhi" to "Android Developer",
    "Email" to "admin@androidcoding.in",
    "facebook" to "androidcoding.in",
    "instagram" to "androidcoding.in"
)

db.collection("users")
    .add(user)
    .addOnSuccessListener { documentReference ->
        Log.d("UserUpload", "DocumentSnapshot added with ID: ${documentReference.id}")
    }
    .addOnFailureListener { e ->
        Log.w("UserUpload", "Error adding document", e)
    }

readData :

Read data from firebase firestore.Using realtime listeners we can read data from collections “users”.

db.collection("users")
    .get()
    .addOnSuccessListener { result ->
        Log.d("UserDownload", "Size " + result.size())
        for (document in result) {
            Log.d("UserDownload", "${document.id} => ${document.data}")
        }
    }
    .addOnFailureListener { exception ->
        Log.w("UserDownload", "Error getting documents.", exception)
    }

Firebase Firestore Full Code :

Presenting the complete source code for Firebase Firestore integration in your Flutter app.

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import androidx.appcompat.app.AppCompatActivity;
import com.google.firebase.firestore.ktx.firestore;
import com.google.firebase.ktx.Firebase;
import kotlinx.android.synthetic.main.activity_main.*;

class MainActivity : AppCompatActivity(), View.OnClickListener {
    val db = Firebase.firestore

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        btn_write_data.setOnClickListener(this)
        btn_read_data.setOnClickListener(this)
    }

    override fun onClick(v: View?) {
        when(v!!.id){
            R.id.btn_write_data -> {
                val user = hashMapOf(
                    "id" to 2,
                    "Abhi" to "Android Developer",
                    "Email" to "admin@androidcoding.in",
                    "facebook" to "androidcoding.in",
                    "instagram" to "androidcoding.in"
                )
                db.collection("users")
                    .add(user)
                    .addOnSuccessListener { documentReference ->
                        Log.d("UserUpload", "DocumentSnapshot added with ID: ${documentReference.id}")
                    }
                    .addOnFailureListener { e ->
                        Log.w("UserUpload", "Error adding document", e)
                    }
            }
            R.id.btn_read_data -> {
                db.collection("users")
                    .get()
                    .addOnSuccessListener { result ->
                        Log.d("UserDownload"," Size "+result.size())
                        for (document in result) {
                            Log.d("UserDownload", "${document.id} => ${document.data}")
                        }
                    }
                    .addOnFailureListener { exception ->
                        Log.w("UserDownload", "Error getting documents.", exception)
                    }
            }
        }
    }
}

If you have any questions about the Firebase Firestore tutorial, feel free to ask in the comment section below.

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