Feature/channel first impl

app/build.gradle

@@ -27,6 +27,7 @@ android {
 
 dependencies {
     def ktx_version = "2.0.0"
+    def kotlin_coroutines_version = "1.0.1"
 
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
@@ -39,6 +40,10 @@ dependencies {
     implementation "androidx.lifecycle:lifecycle-viewmodel-ktx:$ktx_version"
     implementation project (':ktandroidarchitecturecore')
     testImplementation 'junit:junit:4.12'
+
+    implementation 'androidx.paging:paging-runtime-ktx:2.1.0'
+
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$kotlin_coroutines_version"
     androidTestImplementation 'androidx.test:runner:1.1.1'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
 }

app/src/main/java/com/sysdata/kt/ktandroidarchitecture/DIUtils.kt

@@ -0,0 +1,17 @@
+package com.sysdata.kt.ktandroidarchitecture
+
+import com.sysdata.kt.ktandroidarchitecture.ui.Note
+import it.sysdata.ktandroidarchitecturecore.interactor.Channel
+
+class DIUtils {
+
+    private object Holder {
+        val INSTANCE = Channel<Note>()
+    }
+
+    companion object {
+        val channel: Channel<Note> by lazy {
+            Holder.INSTANCE
+        }
+    }
+}

app/src/main/java/com/sysdata/kt/ktandroidarchitecture/ui/LoginActivity.kt

@@ -1,17 +1,18 @@
 package com.sysdata.kt.ktandroidarchitecture.ui
 
-import android.app.Activity
-import androidx.lifecycle.ViewModelProvider
-import androidx.lifecycle.ViewModelProviders
 import android.os.Bundle
+
 import android.text.Editable
 import android.text.TextWatcher
 import android.view.View
 import android.widget.Toast
 import androidx.fragment.app.FragmentActivity
+import androidx.lifecycle.ViewModelProviders
+import androidx.paging.PagedList
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
 import com.sysdata.kt.ktandroidarchitecture.R
 import com.sysdata.kt.ktandroidarchitecture.repository.model.UIUserLogged
-import com.sysdata.kt.ktandroidarchitecture.repository.model.UserLogged
 import com.sysdata.kt.ktandroidarchitecture.usecase.LoginActionParams
 import com.sysdata.kt.ktandroidarchitecture.viewmodel.LoginViewModel
 import it.sysdata.ktandroidarchitecturecore.exception.Failure
@@ -20,6 +21,7 @@ import kotlinx.android.synthetic.main.activity_login.*
 class LoginActivity : FragmentActivity(), View.OnClickListener, TextWatcher {
 
     private var viewModel : LoginViewModel? = null
+    private var adapter: PagedListAdapterImpl? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -37,6 +39,28 @@ class LoginActivity : FragmentActivity(), View.OnClickListener, TextWatcher {
 
         viewModel?.actionLogin?.observe(this, ::onUserLoggged)
         viewModel?.actionLogin?.observeFailure(this, ::onLoginFailed)
+
+        viewModel?.channelNotes?.initDatasource(pageSize = 10)
+
+        adapter = PagedListAdapterImpl {
+            viewModel?.channelPostNotes?.postData(it)
+        }
+
+        recycler_view.layoutManager = LinearLayoutManager(this, RecyclerView.VERTICAL, false)
+        recycler_view.adapter = adapter
+
+        viewModel?.channelNotes?.observe(this,::onPostNote)
+        viewModel?.channelPostNotes?.observe(this, ::onReceivePost)
+    }
+
+    private fun onReceivePost(note: Note?) {
+        Toast.makeText(this, "note : $note", Toast.LENGTH_SHORT).show()
+    }
+
+    private fun onPostNote(list: PagedList<Note>?) {
+        list?.let {
+            adapter?.submitList(list)
+        }
     }
 
     private fun onLoginFailed(failure: Failure?) {

app/src/main/java/com/sysdata/kt/ktandroidarchitecture/ui/Note.kt

@@ -0,0 +1,18 @@
+package com.sysdata.kt.ktandroidarchitecture.ui
+
+import androidx.recyclerview.widget.DiffUtil
+import java.util.*
+
+data class Note(val index:Int, val noteId: String = UUID.randomUUID().toString()) {
+    companion object {
+        val DiffCallback = object : DiffUtil.ItemCallback<Note>() {
+            override fun areItemsTheSame(oldItem: Note, newItem: Note): Boolean
+                    = oldItem.noteId == newItem.noteId
+
+            override fun areContentsTheSame(oldItem: Note, newItem: Note): Boolean
+                    = oldItem.noteId == newItem.noteId && oldItem.title == newItem.title && oldItem.content == newItem.content
+        }
+    }
+    var title: String = ""
+    var content: String = ""
+}

app/src/main/java/com/sysdata/kt/ktandroidarchitecture/ui/NoteDataSource.kt

@@ -0,0 +1,5 @@
+package com.sysdata.kt.ktandroidarchitecture.ui
+
+import it.sysdata.ktandroidarchitecturecore.BasePositionalDatasource
+
+class NoteDataSource: BasePositionalDatasource<Note>()

app/src/main/java/com/sysdata/kt/ktandroidarchitecture/ui/PagedListAdapterImpl.kt

@@ -0,0 +1,37 @@
+package com.sysdata.kt.ktandroidarchitecture.ui
+
+import android.util.Log
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.TextView
+import androidx.paging.PagedListAdapter
+import androidx.recyclerview.widget.RecyclerView
+import com.sysdata.kt.ktandroidarchitecture.R
+
+class PagedListAdapterImpl(val onClick: (Note) -> Unit) : PagedListAdapter<Note, PagedListAdapterImpl.ListItemViewHolder>(Note.DiffCallback) {
+    class ListItemViewHolder(val view: View): RecyclerView.ViewHolder(view) {
+        var note: Note? = null
+        set(value) {
+            if(value != null){
+                val tv: TextView = view.findViewById(R.id.itemText)
+                tv.text = value.toString()
+            }
+            field = value
+        }
+    }
+
+    companion object {
+        private val TAG = this::class.java.simpleName
+    }
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ListItemViewHolder
+            = ListItemViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.note_list_item, parent, false))
+
+    override fun onBindViewHolder(holder: ListItemViewHolder, position: Int) {
+        Log.d(TAG, "Binding view holder at position $position")
+        holder.note = getItem(position)
+        holder.view.setOnClickListener { onClick(holder.note!!) }
+    }
+
+}

app/src/main/java/com/sysdata/kt/ktandroidarchitecture/ui/TestDataSource.kt

@@ -0,0 +1,58 @@
+package com.sysdata.kt.ktandroidarchitecture.ui
+
+import androidx.paging.ItemKeyedDataSource
+
+class TestDataSource: ItemKeyedDataSource<Int, Note>(){
+
+    private val datas = listOf(Note(1), Note(2), Note(3), Note(4), Note(5))
+
+    override fun loadInitial(params: LoadInitialParams<Int>, callback: LoadInitialCallback<Note>) {
+        val requestedLoadSize = params.requestedLoadSize
+        val requestedInitialKey = params.requestedInitialKey ?: 0
+
+        val initItem = datas.firstOrNull { it.index == requestedInitialKey }
+        val initIndex = initItem?.let {datas.indexOf(initItem)} ?: 0
+        val newData = getSubList(initIndex, initIndex + requestedLoadSize)
+        callback.onResult(newData)
+    }
+
+    private fun getSubList(initIndex: Int, finalIndex: Int): MutableList<Note> {
+        val newData = mutableListOf<Note>()
+        for (i in initIndex until finalIndex) {
+            newData.add(datas[i % datas.size])
+        }
+        return newData
+    }
+
+    override fun loadAfter(params: LoadParams<Int>, callback: LoadCallback<Note>) {
+        val key = params.key
+        val requestedLoadSize = params.requestedLoadSize
+
+        val initItem = datas.firstOrNull { it.index == key }
+        val initIndex = initItem?.let {datas.indexOf(initItem)} ?: 0
+        val newData = getSubList(initIndex, initIndex + requestedLoadSize)
+        callback.onResult(newData)
+    }
+
+    override fun loadBefore(params: LoadParams<Int>, callback: LoadCallback<Note>) {
+        val key = params.key
+        val requestedLoadSize = params.requestedLoadSize
+
+        val initItem = datas.firstOrNull { it.index == key }
+        var initIndex = initItem?.let {datas.indexOf(initItem)} ?: 0
+        var finalIndex = initIndex
+        if(initIndex - requestedLoadSize >= 0){
+            initIndex -= requestedLoadSize
+        } else {
+            initIndex = 0
+            finalIndex = initIndex + requestedLoadSize
+        }
+        val newData = getSubList(initIndex, finalIndex)
+        callback.onResult(newData)
+    }
+
+    override fun getKey(item: Note): Int {
+        return item.index
+    }
+
+}

app/src/main/java/com/sysdata/kt/ktandroidarchitecture/viewmodel/LoginViewModel.kt

@@ -1,15 +1,25 @@
 package com.sysdata.kt.ktandroidarchitecture.viewmodel
 
+import com.sysdata.kt.ktandroidarchitecture.DIUtils
 import com.sysdata.kt.ktandroidarchitecture.repository.model.UIUserLogged
 import com.sysdata.kt.ktandroidarchitecture.repository.model.UserLogged
+import com.sysdata.kt.ktandroidarchitecture.ui.Note
+import com.sysdata.kt.ktandroidarchitecture.ui.NoteDataSource
+import com.sysdata.kt.ktandroidarchitecture.ui.TestDataSource
 import com.sysdata.kt.ktandroidarchitecture.usecase.LoginActionParams
 import com.sysdata.kt.ktandroidarchitecture.usecase.LoginUseCase
-import it.sysdata.ktandroidarchitecturecore.interactor.Action
+import it.sysdata.ktandroidarchitecturecore.interactor.*
 import it.sysdata.ktandroidarchitecturecore.platform.BaseViewModel
 
 class LoginViewModel: BaseViewModel() {
 
     val actionLogin = Action.Builder<LoginActionParams,UserLogged, UIUserLogged>()
             .useCase(LoginUseCase::class.java)
             .buildWithUiModel { UIUserLogged(it.username) }
+
+    val channelNotes = DataSourceChannel.Builder<Int, Note>()
+            .dataSource(TestDataSource::class.java)
+            .build()
+
+    val channelPostNotes = DIUtils.channel
 }

app/src/main/res/layout/activity_login.xml

@@ -1,6 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    android:orientation="vertical" android:layout_width="match_parent"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:orientation="vertical"
+    android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:gravity="center_horizontal"
     android:padding="50dp"
@@ -40,4 +42,10 @@
         android:layout_marginTop="10dp"
         android:background="@android:drawable/btn_default" />
 
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/recycler_view"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        tools:listitem="@layout/note_list_item" />
+
 </LinearLayout>

app/src/main/res/layout/note_list_item.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:orientation="vertical" android:layout_width="match_parent"
+    android:layout_height="wrap_content">
+
+    <TextView
+        android:id="@+id/itemText"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:textSize="16sp"
+        android:padding="8dp"
+        android:textColor="#000"
+        />
+
+</LinearLayout>

ktandroidarchitecturecore/build.gradle

@@ -64,6 +64,7 @@ dependencies {
     implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$kotlin_coroutines_version"
     implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$kotlin_coroutines_version"
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+    implementation 'androidx.paging:paging-runtime-ktx:2.1.0'
 }
 
 repositories {