過濾ArrayList確定Firebase實時資料庫參考子項

我正在嘗試RecyclerViews根據孩子在我的一個 RTDB 參考中具有的屬性過濾三個活動。在我的 上ServiceActivity，我有這三個RecyclerViews，我需要幫助來了解我需要做什么來執行過濾器。我是否需要ArrayList為每個category屬性名稱創建一個空名稱，然后對每個屬性名稱執行過濾功能？或者我將如何執行此操作？謝謝！

我有的

一個 RTDB 參考子

服務活動.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())
            }
        })

}

uj5u.com熱心網友回復：

您從 Firebase 加載完全相同的資料 3 次。雖然客戶端足夠聰明，可以為您洗掉這些查詢的重復資料，但最好只處理一次相同的資料。

如何一次創建三個視圖、串列和配接器，然后用這個片段加載每個視圖的資料？像這樣的東西：

private fun loadDataForRecyclerViews() {
    jobServicesDatabaseRef.orderByChild("jobName").addValueEventListener(object: ValueEventListener {
        @SuppressLint("NotifyDataSetChanged")
        override fun onDataChange(snapshot: DataSnapshot) {
            jobServices.clear()
            for (snap in snapshot.children) {
                // ?? Load the category and the job
                val category = category
                val jobService = (category ,
                    snap.child("jobName").getValue(String::class.java)!! , snap.child("jobImageUrl").getValue(String::class.java)!! ,
                    snap.child("jobServiceImageUrl").getValue(String::class.java)!!)

                // ?? Put the job in the correct list based on its category
                if (category == "auto") {
                    autoJobServices.add(jobService)
                }
                else if (category == "home") {
                    homeJobServices.add(jobService)
                }
                else if (category == "personal") {
                    personalJobServices.add(jobService)
                }
            }
            // ?? Refresh all views
            autoJobServicesAdapter.notifyDataSetChanged()
            homeJobServicesAdapter.notifyDataSetChanged()
            personalJobServicesAdapter.notifyDataSetChanged()
        }

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

注意：我沒有編譯這段代碼，只是提供它作為起點。如果您遇到編譯器錯誤，請在發表評論之前嘗試自行修復它。

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