I'm trying to filter three RecyclerViews on an activity based on a property that children have in one of my RTDB references have. On my ServiceActivity, I have the three RecyclerViews and I need help in knowing what I need to do to perform the filters. Do I need to create an empty ArrayList for each category property name and then perform the filter function on each? Or how would I perform this? Thank you!

What I Have

A RTDB Reference Child

ServiceActivity.kt

lateinit var autoJobServicesAdapter: JobServicesAdapter
lateinit var homeJobServicesAdapter: JobServicesAdapter
lateinit var personalJobServicesAdapter: JobServicesAdapter
val jobServices = ArrayList<JobService>()
val jobServicesDatabaseRef = FirebaseDatabase.getInstance().reference.child(REF_JOB_SERVICES)

val autoServices = ArrayList<JobService>()
val homeServices = ArrayList<JobService>()
val personalServices = ArrayList<JobService>()

    private fun setupAutoRecyclerView() {

        autoJobServicesAdapter = JobServicesAdapter(jobServices)

        val autoRecyclerView = findViewById<RecyclerView>(R.id.autoServicesRecyclerView)
        autoRecyclerView.apply {
            layoutManager = LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false)
            adapter = autoJobServicesAdapter
            setHasFixedSize(true)
        }

        jobServicesDatabaseRef.orderByChild("jobName").addValueEventListener(object: ValueEventListener {
            @SuppressLint("NotifyDataSetChanged")
            override fun onDataChange(snapshot: DataSnapshot) {
                jobServices.clear()
                for (snap in snapshot.children) {
                    val jobService = JobService(snap.child("category").getValue(String::class.java)!! ,
                        snap.child("jobName").getValue(String::class.java)!! , snap.child("jobImageUrl").getValue(String::class.java)!! ,
                        snap.child("jobServiceImageUrl").getValue(String::class.java)!!)
                    jobServices.add(jobService)
                }
                autoJobServicesAdapter.notifyDataSetChanged()
            }

            override fun onCancelled(error: DatabaseError) {
                Log.d("ServiceActivity", "LoadPost:onCancelled", error.toException())
            }
        })

    }

    private fun setupHomeRecyclerView() {

        homeJobServicesAdapter = JobServicesAdapter(jobServices)

        val homeRecyclerView = findViewById<RecyclerView>(R.id.homeServicesRecyclerView)
        homeRecyclerView.apply {
            layoutManager = LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false)
            adapter = homeJobServicesAdapter
            setHasFixedSize(true)
        }

        jobServicesDatabaseRef.orderByChild("jobName").addValueEventListener(object: ValueEventListener {
            @SuppressLint("NotifyDataSetChanged")
            override fun onDataChange(snapshot: DataSnapshot) {
                jobServices.clear()
                for (snap in snapshot.children) {
                    val jobService = JobService(snap.child("category").getValue(String::class.java)!! ,
                        snap.child("jobName").getValue(String::class.java)!! , snap.child("jobImageUrl").getValue(String::class.java)!! ,
                        snap.child("jobServiceImageUrl").getValue(String::class.java)!!)
                    jobServices.add(jobService)
                }
                homeJobServicesAdapter.notifyDataSetChanged()
            }

            override fun onCancelled(error: DatabaseError) {
                Log.d("ServiceActivity", "LoadPost:onCancelled", error.toException())
            }
        })

    }

    private fun setupPersonalRecyclerView() {

        personalJobServicesAdapter = JobServicesAdapter(jobServices)

        val personalRecyclerView = findViewById<RecyclerView>(R.id.personalServicesRecyclerView)
        personalRecyclerView.apply {
            layoutManager = LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false)
            adapter = personalJobServicesAdapter
            setHasFixedSize(true)
        }

        jobServicesDatabaseRef.orderByChild("jobName").addValueEventListener(object: ValueEventListener {
            @SuppressLint("NotifyDataSetChanged")
            override fun onDataChange(snapshot: DataSnapshot) {
                jobServices.clear()
                for (snap in snapshot.children) {
                    val jobService = JobService(snap.child("category").getValue(String::class.java)!! ,
                        snap.child("jobName").getValue(String::class.java)!! , snap.child("jobImageUrl").getValue(String::class.java)!! ,
                        snap.child("jobServiceImageUrl").getValue(String::class.java)!!)
                    jobServices.add(jobService)
                }
                personalJobServicesAdapter.notifyDataSetChanged()
            }

            override fun onCancelled(error: DatabaseError) {
                Log.d("ServiceActivity", "LoadPost:onCancelled", error.toException())
            }
        })

}

CodePudding user response：

You're loading the exact same data from Firebase three times. While the client is smart enough to deduplicate these queries for you, it's still better to only process the same data once.

How about creating the three views, list, and adapters all at once, and then loading the data for each with this single snippet? Something like this:

private fun loadDataForRecyclerViews() {
    jobServicesDatabaseRef.orderByChild("jobName").addValueEventListener(object: ValueEventListener {
        @SuppressLint("NotifyDataSetChanged")
        override fun onDataChange(snapshot: DataSnapshot) {
            jobServices.clear()
            for (snap in snapshot.children) {
                //