Java Android App Development Course, Firebase Storage

Data storage is a very important part of Android development. There are various ways to store app data, including local databases, file systems, and cloud databases. In this tutorial, we will discuss storage using Firebase, a cloud service provided by Google. Firebase Storage offers a convenient way to store and manage images, videos, audio files, and more. In this tutorial, we will learn how to set up Firebase Storage and how to use it in an Android app.

What is Firebase?

Firebase is a mobile development platform provided by Google that offers various features, including databases, authentication, hosting, and storage. In particular, Firebase Storage is useful for storing and managing different types of files in the cloud. By using Firebase, you can easily manage data without having to operate a backend server.

Key Features

  • Real-time database
  • Cloud storage
  • User authentication
  • Analytics tools
  • Hosting

Setting Up Firebase Storage

To use Firebase Storage, you first need to create a Firebase project and connect it to your Android app. Below are the steps to set up a Firebase project and integrate it into an Android app.

1. Create a Firebase Project

  1. Access the Firebase console: Firebase Console.
  2. Create a new project. Enter a project name and enable analytics if needed.
  3. Once the project is created, go to “Project Settings.”

2. Add Android App

  1. In the project settings page, click the “Add Application” button and select the Android icon.
  2. Enter the package name for the app (e.g., com.example.myapp).
  3. Enter the SHA-1 value of the app’s signing certificate. (Optional)
  4. After registering the app, download the provided google-services.json file and add it to the app/ directory of your Android project.

3. Configure Gradle

You need to modify the build.gradle file to use the Firebase SDK.

build.gradle (Project level)
buildscript {
    dependencies {
        classpath 'com.google.gms:google-services:4.3.10' // Update to the latest version
    }
}

build.gradle (App level)
apply plugin: 'com.android.application'
apply plugin: 'com.google.gms.google-services'

dependencies {
    implementation 'com.google.firebase:firebase-storage:20.2.0' // Update to the latest version
}

Using Firebase Storage in Android App

Now that we have set up Firebase Storage, let’s learn how to upload and download files. The following example shows the code for a simple Android app that uploads and downloads images.

1. Implementing Image Upload Functionality

import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.firebase.storage.FirebaseStorage;
import com.google.firebase.storage.StorageReference;

import java.io.IOException;

public class MainActivity extends AppCompatActivity {

    private static final int PICK_IMAGE_REQUEST = 1;
    private Uri imageUri;

    private ImageView imageView;
    private Button uploadButton;

    private FirebaseStorage firebaseStorage;
    private StorageReference storageReference;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        imageView = findViewById(R.id.image_view);
        uploadButton = findViewById(R.id.upload_button);

        firebaseStorage = FirebaseStorage.getInstance();
        storageReference = firebaseStorage.getReference("uploads");

        uploadButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                uploadImage();
            }
        });
        
        // Open image picker
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(Intent.createChooser(intent, "Select Image"), PICK_IMAGE_REQUEST);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.getData() != null) {
            imageUri = data.getData();
            try {
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), imageUri);
                imageView.setImageBitmap(bitmap);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private void uploadImage() {
        if (imageUri != null) {
            StorageReference fileReference = storageReference.child(System.currentTimeMillis() + ".jpg");
            fileReference.putFile(imageUri)
                    .addOnSuccessListener(new OnSuccessListener() {
                        @Override
                        public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
                            Toast.makeText(MainActivity.this, "Upload successful", Toast.LENGTH_SHORT).show();
                        }
                    })
                    .addOnFailureListener(new OnFailureListener() {
                        @Override
                        public void onFailure(@NonNull Exception e) {
                            Toast.makeText(MainActivity.this, e.getMessage(), Toast.LENGTH_SHORT).show();
                        }
                    });
        } else {
            Toast.makeText(this, "No image selected", Toast.LENGTH_SHORT).show();
        }
    }
}

2. Implementing Image Download Functionality

Let’s add a feature to download the uploaded images. The downloading process will be done by fetching the image via its URL and displaying it in an ImageView.

private void downloadImage(String imageUrl, ImageView imageView) {
    Glide.with(this)
            .load(imageUrl)
            .into(imageView);
}

// Example call
downloadImage("https://firebasestorage.googleapis.com/v0/b/your-app-id.appspot.com/o/uploads%2Fimage.jpg?alt=media", imageView);

Handling Errors During Image Upload

You can add error handling for various errors that may occur while uploading files to show error messages to the user. In the example, we will learn how to check the rules of Firebase Storage or verify network connectivity.

private void handleUploadError(Exception e) {
    if (e instanceof StorageException) {
        StorageException storageException = (StorageException) e;
        if (storageException.getErrorCode() == StorageException.ERROR_NOT_AUTHORIZED) {
            Toast.makeText(this, "Unauthorized access", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(this, "Error uploading image", Toast.LENGTH_SHORT).show();
        }
    } else {
        Toast.makeText(this, "Network error", Toast.LENGTH_SHORT).show();
    }
}

Conclusion

In this tutorial, we learned how to set up Firebase Storage and how to upload and download files in an Android app. Firebase provides a variety of cloud-based services, making it a great help for app development. Additionally, combining Firebase with authentication and database features can lead to the development of even more powerful apps. In the next session, we will explore the database features of Firebase.

References

I hope this tutorial will be of great help in your Android app development!