FireBase Database to RecyclerView

FirebaseUI for Realtime Database

Check out this project on firebaseopensource.com!

https://firebaseopensource.com/projects/firebase/firebaseui-android/database/readme/

Add Dependency

// FirebaseUI for Firebase Realtime Database
implementation ("com.firebaseui:firebase-ui-database:8.0.2")

Retrieve Data from FireBase DataBase

val path = "Creative/katargam"
val query: Query = FirebaseDatabase.getInstance().reference.child(path)

Using FirebaseUI to populate a RecyclerView

Choosing an adapter

• FirebaseRecyclerAdapter — binds a Query to a RecyclerView and responds to all real-time events included items being added, removed, moved, or changed. Best used with small result sets since all results are loaded at once.

• FirebaseRecyclerPagingAdapter — binds a Query to a RecyclerView by loading data in pages. Best used with large, static data sets. Real-time events are not respected by this adapter, so it will not detect new/removed items or changes to items already loaded.

Using the FirebaseRecyclerAdapter

// class level scope
lateinit var options: FirebaseRecyclerOptions<Mydata?>

// in onCreate intialize this
options = FirebaseRecyclerOptions.Builder<Mydata>()
							.setQuery(query, Mydata::class.java).build()

// in some case you need to specify type explicitly than use Any data type for internal type
// val adapter: FirebaseRecyclerAdapter<*, *> = ...
// othervise this will work in 99% situations.
val adapter = object : FirebaseRecyclerAdapter<Mydata?, MyViewHolder>(options) {
            override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
                // Create a new instance of the ViewHolder, in this case we are using a custom
                // layout called R.layout.message for each item
                val view: View =
                    LayoutInflater.from(parent.context).inflate(R.layout.item_layout, parent, false)
                return MyViewHolder(view)
            }

            override fun onBindViewHolder(holder: MyViewHolder, position: Int, model: Mydata) {
                holder.name.text = model.name
                Glide.with(this@ViewActivity).load(model.imageurl).into(holder.imgeddd)
            }
        }

    class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var imgeddd: ImageView
        var name: TextView

        init {
            imgeddd = itemView.findViewById(R.id.imgeddd)
            name = itemView.findViewById(R.id.name)
        }
    }
}

FirebaseRecyclerAdapter lifecycle

Start/stop listening

override fun onStart() {
    super.onStart()
    adapter.startListening();
}

override fun onStop() {
    super.onStop()
    adapter.stopListening();
}

Change query and fetch data using firebase recyclerview

• updateOptions() method of adapter allows us to change query of what data to fetch from database by some conditions , this new query will be passed to new options and after that updateOptions( new_option ) method called to fetch new data ,

• adapter.notifyDataSetChanged() method will make new view Item with new data and change recyclerView in UI that looks changes are made.

private fun changeFirList() {

// in this example we have sorted  data between on start date and end date 
// from based on registerDate colummn
    val sDate = binding.startDate.text.toString()
    val eDate = binding.endDate.text.toString()

    query = FirebaseDatabase.getInstance()
        .getReference()
        .child("FIR/Data/${cUser!!.uid}")
        .orderByChild("registerDate")
        .startAt(sDate)
        .endAt(eDate)


    options = FirebaseRecyclerOptions.Builder<FIR>()
        .setQuery(query, FIR::class.java)
        .build()


    adapter.updateOptions(options)
    adapter.notifyDataSetChanged()


}