From 329efb70d7b4fe7f949fd2342eb3a5e13509e70c Mon Sep 17 00:00:00 2001
From: dlwls5201 <dlwls5201@naver.com>
Date: Sun, 12 Jul 2020 17:38:41 +0900
Subject: [PATCH] add paging

---
 .../sfoide/presentation/main/MainActivity.kt  | 33 ++++++++++++++++++-
 .../sfoide/presentation/main/MainViewModel.kt | 30 ++++++++++++++++-
 .../presentation/main/RandomUserAdapter.kt    | 10 ++++++
 3 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/app/src/main/java/com/studyfork/sfoide/presentation/main/MainActivity.kt b/app/src/main/java/com/studyfork/sfoide/presentation/main/MainActivity.kt
index 4c2e812..d46217a 100644
--- a/app/src/main/java/com/studyfork/sfoide/presentation/main/MainActivity.kt
+++ b/app/src/main/java/com/studyfork/sfoide/presentation/main/MainActivity.kt
@@ -2,6 +2,8 @@ package com.studyfork.sfoide.presentation.main
 
 import android.os.Bundle
 import androidx.lifecycle.Observer
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
 import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
 import com.studyfork.sfoide.R
 import com.studyfork.sfoide.base.BaseActivity
@@ -29,16 +31,45 @@ class MainActivity : BaseActivity<ActivityMainBinding>(R.layout.activity_main),
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         binding.model = mainViewModel
-        binding.rvRandomUser.adapter = userAdapter
         binding.srlMainActivity.setOnRefreshListener(this)
 
+        initRecyclerView()
+
         mainViewModel.randomUsers.observe(this, Observer {
             userAdapter.replaceAll(it)
         })
 
+        mainViewModel.addRandomUsers.observe(this, Observer {
+            userAdapter.addItems(it)
+        })
+
         mainViewModel.loadRandomUsers()
     }
 
+    private fun initRecyclerView() {
+        with(binding.rvRandomUser) {
+            adapter = userAdapter
+
+            addOnScrollListener(object : RecyclerView.OnScrollListener() {
+                override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
+                    super.onScrolled(recyclerView, dx, dy)
+
+                    if (dy > 0) {
+                        val lm = recyclerView.layoutManager
+                        if (lm is LinearLayoutManager) {
+                            if (lm.findLastCompletelyVisibleItemPosition() ==
+                                recyclerView.adapter?.itemCount?.minus(1)
+                            ) {
+                                mainViewModel.addRandomUsers()
+                            }
+                        }
+                    }
+
+                }
+            })
+        }
+    }
+
     override fun onRefresh() {
         mainViewModel.loadRandomUsers(true)
     }
diff --git a/app/src/main/java/com/studyfork/sfoide/presentation/main/MainViewModel.kt b/app/src/main/java/com/studyfork/sfoide/presentation/main/MainViewModel.kt
index 9762da7..1aba183 100644
--- a/app/src/main/java/com/studyfork/sfoide/presentation/main/MainViewModel.kt
+++ b/app/src/main/java/com/studyfork/sfoide/presentation/main/MainViewModel.kt
@@ -14,6 +14,9 @@ class MainViewModel(
     private val _randomUsers = MutableLiveData<List<UserItem>>()
     val randomUsers: LiveData<List<UserItem>> get() = _randomUsers
 
+    private val _addRandomUsers = MutableLiveData<List<UserItem>>()
+    val addRandomUsers: LiveData<List<UserItem>> get() = _addRandomUsers
+
     private val _isLoading = MutableLiveData<Boolean>()
     val isLoading: LiveData<Boolean> get() = _isLoading
 
@@ -41,6 +44,32 @@ class MainViewModel(
     }
 
     private var page = 1
+    private var isAdding = false
+
+    fun addRandomUsers() {
+        if (isAdding) {
+            return
+        }
+
+        page++
+        isAdding = true
+
+        compositeDisposable.add(
+            userRepository.getRandomUsers(page)
+                .doOnSubscribe {
+                    showLoading()
+                }
+                .doOnTerminate {
+                    hideLoadingAndRefresh()
+                }
+                .subscribe({
+                    isAdding = false
+                    _addRandomUsers.postValue(it)
+                }) {
+                    Dlog.e(it.message)
+                }
+        )
+    }
 
     private fun showLoading() {
         _isLoading.value = true
@@ -50,5 +79,4 @@ class MainViewModel(
         _isLoading.value = false
         _isRefresh.value = false
     }
-
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/studyfork/sfoide/presentation/main/RandomUserAdapter.kt b/app/src/main/java/com/studyfork/sfoide/presentation/main/RandomUserAdapter.kt
index 82f8342..becd509 100644
--- a/app/src/main/java/com/studyfork/sfoide/presentation/main/RandomUserAdapter.kt
+++ b/app/src/main/java/com/studyfork/sfoide/presentation/main/RandomUserAdapter.kt
@@ -48,6 +48,16 @@ class RandomUserAdapter : RecyclerView.Adapter<BaseViewHolder<ViewDataBinding, U
         notifyDataSetChanged()
     }
 
+    fun addItems(items: List<UserItem>) {
+        val preItemSize = this.items.size
+
+        this.items.run {
+            addAll(items)
+        }
+
+        notifyItemRangeChanged(preItemSize - 1, this.items.size)
+    }
+
     class SampleViewHolder(parent: ViewGroup) :
         BaseViewHolder<ItemUserBinding, UserItem>(parent, R.layout.item_user) {