How to implement Firebase Real-Time database in Android applications.

Setup/Installation:

1. First, install the Firebase SDK (guide)

2. Register your project using the Firebase console

3. After successfuly completing the two steps above, add the following dependency in your application level gradel.

   compile 'com.google.firebase:firebase-database:9.2.1'
   

4. [Optional] Configure your database security rules (reference).

Implementation Sample:

1. Declare and initialize the database reference

   FirebaseDatabase database = FirebaseDatabase.getInstance();
   DatabaseReference myRef = database.getReference("message");
   

You can later create different references to access different nodes

6. Write new data to the database

   myRef.setValue("Writing Demo");
   

7. Read data from the database

    myRef.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        // This method is called once with the initial value and again
        // whenever data at this location is updated.
        String value = dataSnapshot.getValue(String.class);
        Log.d(TAG, "Value is: " + value);
    }
   
    @Override
    public void onCancelled(DatabaseError error) {
        // Failed to read value
        Log.w(TAG, "Failed to read value.", error.toException());
    }
   });