Merge pull request #5 from AdrianKuta/feat/4-upgrade_to_build_gradle_7.0.2

feat: Upgrade to build gradle 7.0.2

.github/workflows/publish.yml

@@ -0,0 +1,38 @@
+name: Publish
+
+on:
+  release:
+    # We'll run this workflow when a new GitHub release is created
+    types: [released]
+
+jobs:
+  publish:
+    name: Release build and publish
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+      - name: Set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          distribution: adopt
+          java-version: 11
+
+        # Builds the release artifacts of the library
+      - name: Release build
+        run: ./gradlew :expandable-recyclerview:assembleRelease
+
+        # Generates other artifacts (javadocJar is optional)
+      - name: Source jar and dokka
+        run: ./gradlew androidSourcesJar javadocJar
+
+        # Runs upload, and then closes & releases the repository
+      - name: Publish to MavenCentral
+        run: ./gradlew publishReleasePublicationToSonatypeRepository --max-workers 1 closeAndReleaseSonatypeStagingRepository
+        env:
+          OSSRH_USERNAME: ${{ secrets.OSSRH_USERNAME }}
+          OSSRH_PASSWORD: ${{ secrets.OSSRH_PASSWORD }}
+          SIGNING_KEY_ID: ${{ secrets.SIGNING_KEY_ID }}
+          SIGNING_PASSWORD: ${{ secrets.SIGNING_PASSWORD }}
+          SIGNING_KEY: ${{ secrets.SIGNING_KEY }}
+          SONATYPE_STAGING_PROFILE_ID: ${{ secrets.SONATYPE_STAGING_PROFILE_ID }}

.github/workflows/test.yml

@@ -0,0 +1,27 @@
+name: Test
+
+on:
+  pull_request:
+    branches:
+      - master
+      - develop
+
+jobs:
+  build:
+    name: Run unit tests
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+      - name: Set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          distribution: adopt
+          java-version: 11
+      # Builds the release artifacts
+      - name: Build project
+        run: ./gradlew assemble
+
+      # Run tests
+      - name: Run tests
+        run: ./gradlew test

.idea/codeStyles/Project.xml

@@ -1,8 +1,5 @@
 <component name="ProjectCodeStyleConfiguration">
   <code_scheme name="Project" version="173">
-    <AndroidXmlCodeStyleSettings>
-      <option name="ARRANGEMENT_SETTINGS_MIGRATED_TO_191" value="true" />
-    </AndroidXmlCodeStyleSettings>
     <JetCodeStyleSettings>
       <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
     </JetCodeStyleSettings>

.idea/compiler.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <bytecodeTargetLevel target="11" />
+  </component>
+</project>

.idea/gradle.xml

@@ -1,10 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="GradleMigrationSettings" migrationVersion="1" />
   <component name="GradleSettings">
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>
+        <option name="testRunner" value="GRADLE" />
         <option name="distributionType" value="DEFAULT_WRAPPED" />
         <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="gradleJvm" value="11" />
         <option name="modules">
           <set>
             <option value="$PROJECT_DIR$" />
@@ -13,7 +16,6 @@
           </set>
         </option>
         <option name="resolveModulePerSourceSet" value="false" />
-        <option name="testRunner" value="PLATFORM" />
       </GradleProjectSettings>
     </option>
   </component>

.idea/jarRepositories.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="jboss.community" />
+      <option name="name" value="JBoss Community repository" />
+      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="BintrayJCenter" />
+      <option name="name" value="BintrayJCenter" />
+      <option name="url" value="https://jcenter.bintray.com/" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="Google" />
+      <option name="name" value="Google" />
+      <option name="url" value="https://dl.google.com/dl/android/maven2/" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="MavenRepo" />
+      <option name="name" value="MavenRepo" />
+      <option name="url" value="https://repo.maven.apache.org/maven2/" />
+    </remote-repository>
+  </component>
+</project>

.idea/misc.xml

@@ -1,6 +1,16 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+  <component name="DesignSurface">
+    <option name="filePathToZoomLevelMap">
+      <map>
+        <entry key="app/src/main/res/layout/activity_main.xml" value="0.18020833333333333" />
+        <entry key="app/src/main/res/layout/item_level_1.xml" value="0.32916666666666666" />
+        <entry key="app/src/main/res/layout/item_level_2.xml" value="0.32916666666666666" />
+        <entry key="app/src/main/res/layout/item_level_3.xml" value="0.2824074074074074" />
+      </map>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" project-jdk-name="1.8" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
   <component name="ProjectType">

.idea/runConfigurations.xml

@@ -1,12 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="RunConfigurationProducerService">
-    <option name="ignoredProducers">
-      <set>
-        <option value="org.jetbrains.plugins.gradle.execution.test.runner.AllInPackageGradleConfigurationProducer" />
-        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestClassGradleConfigurationProducer" />
-        <option value="org.jetbrains.plugins.gradle.execution.test.runner.TestMethodGradleConfigurationProducer" />
-      </set>
-    </option>
-  </component>
-</project>

README.md

@@ -1,11 +1,106 @@
 # Multilevel Expandable RecyclerView
 
-[![maven](https://img.shields.io/maven-central/v/com.github.adriankuta/expandable-recyclerView?style=plastic)](https://search.maven.org/artifact/com.github.adriankuta/expandable-recyclerView)
+[![maven](https://img.shields.io/maven-central/v/com.github.adriankuta/expandable-recyclerView?style=plastic)](https://mvnrepository.com/artifact/com.github.adriankuta/expandable-recyclerView)
 [![License](https://img.shields.io/github/license/AdrianKuta/Expandable-RecyclerView?style=plastic)](https://github.com/AdrianKuta/Expandable-RecyclerView/blob/master/LICENSE)
 [![CircleCI](https://img.shields.io/circleci/build/github/AdrianKuta/Expandable-RecyclerView/master?label=CircleCI&style=plastic&logo=circleci)](https://circleci.com/gh/AdrianKuta/Expandable-RecyclerView)
 
-Library is currently during implementation! It is **not** ready to use yet :/
+With this adapter you can add expand feature to regular RecyclerView.
 
-Final version will be released soon.
+All objects are store in [Tree (Data structure)](https://github.com/AdrianKuta/Tree-Data-Structure), so adapter can create multilevel expandable groups.
 
-![Release date](https://img.shields.io/date/1580493319?label=Expected%20release&style=for-the-badge)
+Under the hood, the tree is flattened to simple list, so from RecyclerView's point of view it can operate as usual.
+
+
+<img src="https://github.com/AdrianKuta/Expandable-RecyclerView/blob/master/Demo.gif" width="400" />
+
+## Download
+
+    implementation "com.github.adriankuta:expandable-recyclerView:$latest_versions"
+    
+## Usage
+To use expandable adapter we just have to expand our Adapter class with `ExpandableRecyclerViewAdapter<T, VH>`,
+where `T` is data type on which adapter will operate, `VH` is ViewHolder type.
+
+```kotlin
+class ExpandableAdapter: ExpandableRecyclerViewAdapter<String, RecyclerView.ViewHolder>() {
+    
+    
+    override fun getTreeNodes(): ExpandableTreeNode<String> {
+        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }
+
+    override fun onBindViewHolder(
+        holder: RecyclerView.ViewHolder,
+        treeNode: ExpandableTreeNode<String>,
+        nestLevel: Int
+    ) {
+        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }
+
+    override fun onCreateViewHolder(parent: ViewGroup, nestLevel: Int): RecyclerView.ViewHolder {
+        TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
+    }
+}
+```    
+
+`ExpandableRecyclerViewAdapter` has build-in methods to control expandable groups:
+```kotlin
+fun toggleGroup(expandableTreeNode: ExpandableTreeNode<T>)
+
+fun expand(expandableTreeNode: ExpandableTreeNode<T>)
+
+fun collapse(expandableTreeNode: ExpandableTreeNode<T>)
+```
+
+Information if group is expanded or not is stored inside `ExpandableTreeNode` class
+
+
+### Creating tree
+
+There are different ways to create tree. The easiest way is to use extensions methods prepared specially for kotlin:
+
+```kotlin
+val tree = 
+    expandableTree("World") {
+        child("North America") {
+            child("USA")
+        }
+        child("Europe") {
+            child("Poland") {
+                child("Warsaw")
+            }
+            child("Germany")
+        }
+        child("Asia") {
+            child("China")
+        }
+    }
+```
+
+But in case when you want create tree at runtime, you can use `ExpandableTreeNode<T>` class to build tree:
+
+```kotlin
+val root = ExpandableTreeNode("World")
+val northA = ExpandableTreeNode("North America")
+val europe = ExpandableTreeNode("Europe")
+val asia = ExpandableTreeNode("Asia")
+
+root.addChild(northA)
+root.addChild(europe)
+root.addChild(asia)
+
+val poland = ExpandableTreeNode("Poland")
+europe.addChild(poland)
+// etc.
+```
+
+## Sample
+
+Full example of this library is available in app module.
+
+## Contribution
+
+Project is still during development and improvements.
+Issues with BUGs or suggestions are welcome.
+
+Also please feel free to fork library and contribute to project! ;-)

app/build.gradle

@@ -1,16 +1,14 @@
 apply plugin: 'com.android.application'
-
 apply plugin: 'kotlin-android'
-
-apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-kapt'
 
 android {
-    compileSdkVersion 29
-    buildToolsVersion "29.0.2"
+    compileSdkVersion 31
+    buildToolsVersion "31.0.0"
     defaultConfig {
         applicationId "com.github.adriankuta"
         minSdkVersion 23
-        targetSdkVersion 29
+        targetSdkVersion 31
         versionCode 1
         versionName "1.0"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
@@ -21,15 +19,22 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
     }
+    buildFeatures {
+        viewBinding true
+    }
+    dataBinding {
+        enabled = true
+    }
 }
 
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
-    implementation 'androidx.appcompat:appcompat:1.1.0'
-    implementation 'androidx.core:core-ktx:1.1.0'
-    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
-    testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
-    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+    implementation 'androidx.appcompat:appcompat:1.3.1'
+    implementation 'androidx.core:core-ktx:1.6.0'
+    implementation 'androidx.constraintlayout:constraintlayout:2.1.0'
+    implementation 'com.github.adriankuta:expandable-recyclerView:1.0.0'
+    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
 }

app/src/main/AndroidManifest.xml

@@ -9,7 +9,8 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
-        <activity android:name=".MainActivity">
+        <activity android:name=".MainActivity"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

app/src/main/java/com/github/adriankuta/ExpandableAdapter.kt

@@ -0,0 +1,100 @@
+package com.github.adriankuta
+
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.recyclerview.widget.RecyclerView
+import com.github.adriankuta.databinding.ItemLevel1Binding
+import com.github.adriankuta.databinding.ItemLevel2Binding
+import com.github.adriankuta.databinding.ItemLevel3Binding
+import com.github.adriankuta.expandable_recyclerview.ExpandableRecyclerViewAdapter
+import com.github.adriankuta.expandable_recyclerview.ExpandableTreeNode
+import com.github.adriankuta.expandable_recyclerview.expandableTree
+
+class ExpandableAdapter :
+    ExpandableRecyclerViewAdapter<String, ExpandableAdapter.ExpandableViewHolder>() {
+
+    private var tree: ExpandableTreeNode<String>? = null
+
+    fun setTree(tree: ExpandableTreeNode<String>) {
+        this.tree = tree
+        notifyDataSetChanged()
+    }
+
+    override fun getTreeNodes(): ExpandableTreeNode<String> = tree ?: expandableTree("")
+
+    override fun onCreateViewHolder(parent: ViewGroup, nestLevel: Int): ExpandableViewHolder {
+        return when (nestLevel) {
+            1 -> ExpandableViewHolder.Level1(parent.inflateLevel1())
+            2 -> ExpandableViewHolder.Level2(parent.inflateLevel2())
+            3 -> ExpandableViewHolder.Level3(parent.inflateLevel3())
+            else -> throw IllegalArgumentException("Not implemented ViewHolder for nest level: $nestLevel")
+        }
+    }
+
+    override fun onBindViewHolder(
+        holder: ExpandableViewHolder,
+        treeNode: ExpandableTreeNode<String>,
+        nestLevel: Int
+    ) {
+        holder.bind(treeNode) {
+            toggleGroup(it)
+        }
+    }
+
+    sealed class ExpandableViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
+
+        class Level1(private val binding: ItemLevel1Binding) : ExpandableViewHolder(binding.root) {
+            override fun bind(
+                node: ExpandableTreeNode<String>,
+                onClickListener: ((ExpandableTreeNode<String>) -> Unit)?
+            ) {
+                binding.node = node
+                binding.root.setOnClickListener { onClickListener?.invoke(node) }
+                binding.executePendingBindings()
+            }
+        }
+
+        class Level2(private val binding: ItemLevel2Binding) : ExpandableViewHolder(binding.root) {
+            override fun bind(
+                node: ExpandableTreeNode<String>,
+                onClickListener: ((ExpandableTreeNode<String>) -> Unit)?
+            ) {
+                binding.node = node
+                binding.root.setOnClickListener { onClickListener?.invoke(node) }
+                binding.executePendingBindings()
+            }
+        }
+
+        class Level3(private val binding: ItemLevel3Binding) : ExpandableViewHolder(binding.root) {
+            override fun bind(
+                node: ExpandableTreeNode<String>,
+                onClickListener: ((ExpandableTreeNode<String>) -> Unit)?
+            ) {
+                binding.node = node
+                binding.root.setOnClickListener { onClickListener?.invoke(node) }
+                binding.executePendingBindings()
+            }
+        }
+
+
+        abstract fun bind(
+            node: ExpandableTreeNode<String>,
+            onClickListener: ((ExpandableTreeNode<String>) -> Unit)? = null
+        )
+
+    }
+
+    private fun ViewGroup.inflateLevel1(): ItemLevel1Binding {
+        return ItemLevel1Binding.inflate(LayoutInflater.from(context), this, false)
+    }
+
+    private fun ViewGroup.inflateLevel2(): ItemLevel2Binding {
+        return ItemLevel2Binding.inflate(LayoutInflater.from(context), this, false)
+    }
+
+    private fun ViewGroup.inflateLevel3(): ItemLevel3Binding {
+        return ItemLevel3Binding.inflate(LayoutInflater.from(context), this, false)
+    }
+
+}

app/src/main/java/com/github/adriankuta/MainActivity.kt

@@ -1,12 +1,42 @@
 package com.github.adriankuta
 
-import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.github.adriankuta.databinding.ActivityMainBinding
+import com.github.adriankuta.expandable_recyclerview.expandableTree
 
 class MainActivity : AppCompatActivity() {
 
+    private lateinit var binding: ActivityMainBinding
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
+        binding = ActivityMainBinding.inflate(layoutInflater)
+
+        val tree = expandableTree("World") {
+            child("North America") {
+                child("USA")
+            }
+            child("Europe") {
+                child("Poland") {
+                    child("Warsaw")
+                }
+                child("Germany")
+            }
+            child("Asia") {
+                child("China")
+            }
+        }
+
+        with(binding) {
+            val adapter = ExpandableAdapter()
+            recyclerView.layoutManager = LinearLayoutManager(this@MainActivity, RecyclerView.VERTICAL, false)
+            recyclerView.adapter = adapter
+
+            adapter.setTree(tree)
+        }
     }
 }

app/src/main/res/drawable/ic_expand_less_black_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M12,8l-6,6 1.41,1.41L12,10.83l4.59,4.58L18,14z"/>
+</vector>

app/src/main/res/drawable/ic_expand_more_black_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M16.59,8.59L12,13.17 7.41,8.59 6,10l6,6 6,-6z"/>
+</vector>

app/src/main/res/drawable/ic_last_element.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24.0"
+    android:viewportHeight="24.0">
+
+    <path
+        android:pathData="M12,0 l0,13z"
+        android:strokeWidth="2"
+        android:strokeColor="@android:color/black" />
+
+    <path
+        android:pathData="M12.5,12 l12,0"
+        android:strokeWidth="2"
+        android:strokeColor="@android:color/black" />
+
+</vector>

app/src/main/res/drawable/ic_middle_element.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24.0"
+    android:viewportHeight="24.0">
+
+    <path
+        android:pathData="M12,0 l0,24z"
+        android:strokeWidth="2"
+        android:strokeColor="@android:color/black" />
+
+    <path
+        android:pathData="M13,12 l11,0"
+        android:strokeWidth="2"
+        android:strokeColor="@android:color/black" />
+
+</vector>

app/src/main/res/drawable/ic_vertical_line.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24.0"
+    android:viewportHeight="24.0">
+
+    <path
+        android:pathData="M12,0 l0,24"
+        android:strokeWidth="2"
+        android:strokeColor="@android:color/black" />
+
+</vector>

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

@@ -6,13 +6,13 @@
     android:layout_height="match_parent"
     tools:context=".MainActivity">
 
-    <TextView
-        android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:text="Hello World!"
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/recyclerView"
+        android:layout_width="0dp"
+        android:layout_height="0dp"
         app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintLeft_toLeftOf="parent"
-        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
 </androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/item_level_1.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout>
+
+    <data>
+
+        <variable
+            name="node"
+            type="com.github.adriankuta.expandable_recyclerview.ExpandableTreeNode&lt;String>" />
+
+        <import type="android.view.View" />
+    </data>
+
+    <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:app="http://schemas.android.com/apk/res-auto"
+        xmlns:tools="http://schemas.android.com/tools"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        tools:viewBindingIgnore="true">
+
+        <ImageView
+            android:id="@+id/expand_icon"
+            android:layout_width="24dp"
+            android:layout_height="0dp"
+            android:scaleType="centerInside"
+            android:src="@{node.expanded ? @drawable/ic_expand_more_black_24dp : @drawable/ic_expand_less_black_24dp}"
+            android:visibility="@{node.children.empty ? View.GONE : View.VISIBLE}"
+            app:layout_constraintBottom_toBottomOf="@id/textView"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="@id/textView"
+            tools:src="@drawable/ic_expand_less_black_24dp" />
+
+        <TextView
+            android:id="@+id/textView"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:padding="8dp"
+            android:text="@{node.value}"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toEndOf="@id/expand_icon"
+            app:layout_constraintTop_toTopOf="parent"
+            tools:text="@tools:sample/full_names" />
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</layout>

app/src/main/res/layout/item_level_2.xml

@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout>
+
+    <data>
+
+        <variable
+            name="node"
+            type="com.github.adriankuta.expandable_recyclerview.ExpandableTreeNode&lt;String>" />
+
+        <import type="android.view.View" />
+    </data>
+
+    <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:app="http://schemas.android.com/apk/res-auto"
+        xmlns:tools="http://schemas.android.com/tools"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        tools:viewBindingIgnore="true">
+
+        <ImageView
+            android:id="@+id/expand_icon"
+            android:layout_width="24dp"
+            android:layout_height="0dp"
+            android:layout_marginStart="24dp"
+            android:scaleType="centerInside"
+            android:src="@{node.expanded ? @drawable/ic_expand_more_black_24dp : @drawable/ic_expand_less_black_24dp}"
+            android:visibility="@{node.children.empty ? View.GONE : View.VISIBLE}"
+            app:layout_constraintBottom_toBottomOf="@id/textView"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="@id/textView"
+            tools:src="@drawable/ic_expand_less_black_24dp" />
+
+        <TextView
+            android:id="@+id/textView"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:padding="8dp"
+            android:text="@{node.value}"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toEndOf="@id/expand_icon"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_goneMarginStart="48dp"
+            tools:text="@tools:sample/full_names" />
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</layout>

app/src/main/res/layout/item_level_3.xml

@@ -0,0 +1,46 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout>
+
+    <data>
+
+        <variable
+            name="node"
+            type="com.github.adriankuta.expandable_recyclerview.ExpandableTreeNode&lt;String>" />
+
+        <import type="android.view.View" />
+    </data>
+
+    <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:app="http://schemas.android.com/apk/res-auto"
+        xmlns:tools="http://schemas.android.com/tools"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        tools:viewBindingIgnore="true">
+
+        <ImageView
+            android:id="@+id/expand_icon"
+            android:layout_width="24dp"
+            android:layout_height="0dp"
+            android:layout_marginStart="48dp"
+            android:scaleType="centerInside"
+            android:src="@{node.expanded ? @drawable/ic_expand_more_black_24dp : @drawable/ic_expand_less_black_24dp}"
+            android:visibility="@{node.children.empty ? View.GONE : View.VISIBLE}"
+            app:layout_constraintBottom_toBottomOf="@id/textView"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="@id/textView"
+            tools:src="@drawable/ic_expand_less_black_24dp" />
+
+        <TextView
+            android:id="@+id/textView"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:padding="8dp"
+            android:text="@{node.value}"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toEndOf="@id/expand_icon"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_goneMarginStart="96dp"
+            tools:text="@tools:sample/full_names" />
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</layout>

build.gradle

@@ -1,26 +1,29 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-    ext.kotlin_version = '1.3.61'
+    ext.kotlin_version = '1.5.30'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
 
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.3'
+        classpath 'com.android.tools.build:gradle:7.0.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-        classpath "io.codearte.gradle.nexus:gradle-nexus-staging-plugin:0.21.2"
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }
 }
 
+plugins {
+    id("io.github.gradle-nexus.publish-plugin") version "1.1.0"
+    id("org.jetbrains.dokka") version "1.5.0"
+}
+
 allprojects {
     repositories {
         google()
-        jcenter()
-
+        mavenCentral()
     }
 }
 
@@ -28,4 +31,4 @@ task clean(type: Delete) {
     delete rootProject.buildDir
 }
 
-apply plugin: 'io.codearte.nexus-staging'
+apply from: "${rootDir}/scripts/publish-root.gradle"

expandable-recyclerview/build.gradle

@@ -1,21 +1,19 @@
 apply plugin: 'com.android.library'
 apply plugin: 'kotlin-android'
-apply plugin: 'kotlin-android-extensions'
 
 afterEvaluate {
     generateReleaseBuildConfig.enabled = false
 }
 
 android {
-    compileSdkVersion 29
-    buildToolsVersion "29.0.2"
+    compileSdkVersion 31
+    buildToolsVersion "31.0.0"
 
 
     defaultConfig {
         minSdkVersion 23
-        targetSdkVersion 29
-        versionCode 1
-        versionName "0.0.1-alpha02"
+        targetSdkVersion 31
+        versionName "2.0.0"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         consumerProguardFiles 'consumer-rules.pro'
@@ -32,14 +30,14 @@ android {
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
-    implementation 'androidx.appcompat:appcompat:1.1.0'
-    implementation 'androidx.core:core-ktx:1.1.0'
-    implementation "androidx.recyclerview:recyclerview:1.1.0"
-    implementation "com.github.adriankuta:tree-structure:1.2.0"
+    implementation 'androidx.appcompat:appcompat:1.3.1'
+    implementation 'androidx.core:core-ktx:1.6.0'
+    implementation "androidx.recyclerview:recyclerview:1.2.1"
+    implementation "com.github.adriankuta:tree-structure:2.0.3"
 
-    testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
-    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
 }
 
 ext {
@@ -48,4 +46,4 @@ ext {
     PUBLISH_VERSION = android.defaultConfig.versionName
 }
 
-apply from: "${rootProject.projectDir}/scripts/publish-mavencentral.gradle"
+apply from: "${rootProject.projectDir}/scripts/publish-module.gradle"

expandable-recyclerview/src/main/java/com/github/adriankuta/expandable_recyclerview/ExpandableRecyclerViewAdapter.kt

@@ -3,7 +3,7 @@ package com.github.adriankuta.expandable_recyclerview
 import android.view.ViewGroup
 import androidx.recyclerview.widget.RecyclerView
 
-abstract class MultilevelRecyclerViewAdapter<T, VH : RecyclerView.ViewHolder> :
+abstract class ExpandableRecyclerViewAdapter<T, VH : RecyclerView.ViewHolder> :
     RecyclerView.Adapter<VH>() {
 
     private lateinit var treeNodes: ExpandableTreeNode<T>
@@ -12,25 +12,35 @@ abstract class MultilevelRecyclerViewAdapter<T, VH : RecyclerView.ViewHolder> :
     abstract override fun onCreateViewHolder(parent: ViewGroup, nestLevel: Int): VH
 
     final override fun onBindViewHolder(holder: VH, position: Int) {
-        onBindViewHolder(holder, treeNodes.getVisibleNode(position))
+        val visibleNode = treeNodes.getVisibleNode(position, true)
+        onBindViewHolder(holder, visibleNode, visibleNode.depth())
     }
 
-    abstract fun onBindViewHolder(holder: VH, treeNode: ExpandableTreeNode<T>)
+    abstract fun onBindViewHolder(holder: VH, treeNode: ExpandableTreeNode<T>, nestLevel: Int)
 
     abstract fun getTreeNodes(): ExpandableTreeNode<T>
 
     final override fun getItemCount(): Int {
         treeNodes = getTreeNodes()
-        return treeNodes.getVisibleNodeCount()
+        return treeNodes.getVisibleNodeCount(true) //We don't want to show root element.
     }
 
     final override fun getItemViewType(position: Int): Int {
-
-        return treeNodes.getVisibleNode(position).depth()
+        return treeNodes.getVisibleNode(position, true).depth()
     }
 
     fun toggleGroup(expandableTreeNode: ExpandableTreeNode<T>) {
         expandableTreeNode.expanded = !expandableTreeNode.expanded
         notifyDataSetChanged()
     }
+
+    fun expand(expandableTreeNode: ExpandableTreeNode<T>) {
+        expandableTreeNode.expanded = true
+        notifyDataSetChanged()
+    }
+
+    fun collapse(expandableTreeNode: ExpandableTreeNode<T>) {
+        expandableTreeNode.expanded = false
+        notifyDataSetChanged()
+    }
 }

expandable-recyclerview/src/main/java/com/github/adriankuta/expandable_recyclerview/ExpandableTreeNode.kt

@@ -6,33 +6,78 @@ import com.github.adriankuta.datastructure.tree.TreeNode
 class ExpandableTreeNode<T>(value: T) : TreeNode<T>(value) {
 
     var expanded: Boolean = true
-        set(value) {
-            field = value
-            children.forEach {
-                (it as ExpandableTreeNode).expanded = value
-            }
-        }
 
-    override fun child(value: T, childDeclaration: ChildDeclaration<T>?) {
+    override fun child(value: T, childDeclaration: ChildDeclaration<T>?) : ExpandableTreeNode<T> {
         val newChild = ExpandableTreeNode(value)
         if (childDeclaration != null)
             newChild.childDeclaration()
         addChild(newChild)
+        return newChild
     }
 
-    fun getVisibleNodeCount(): Int {
-        return onlyVisibleItems()
+    /**
+     * @param skipRootNode If `True`, then root node won't be counted.
+     */
+    internal fun getVisibleNodeCount(skipRootNode: Boolean): Int {
+        var size = onlyVisibleItems()
             .size
+
+        if (skipRootNode && size > 0)
+            size--
+
+        return size
     }
 
-    fun getVisibleNode(position: Int): ExpandableTreeNode<T> {
-        return onlyVisibleItems()[position]
+    /**
+     * This function use Pre-order iteration to go through tree:
+     * ```
+     * e.g.
+     *                    1
+     *                  / | \
+     *                 /  |   \
+     *               2    3     4
+     *              / \       / | \
+     *             5    6    7  8  9
+     *            /   / | \
+     *           10  11 12 13
+     *
+     * Output (skipRootNode = false): 1 2 5 10 6 11 12 13 3 4 7 8 9
+     * Output (skipRootNode = true): 2 5 10 6 11 12 13 3 4 7 8 9
+     * ```
+     * @param skipRootNode If `True` root element will be omitted, and position 0 will be for first left child.
+     */
+    internal fun getVisibleNode(position: Int, skipRootNode: Boolean): ExpandableTreeNode<T> {
+        val nodePosition = if (skipRootNode) position + 1 else position
+        return onlyVisibleItems()[nodePosition]
     }
 
-    private fun onlyVisibleItems(): List<ExpandableTreeNode<T>> {
+    /**
+     * @return List of nodes which parent or higher ancestor aren't collapsed.
+     */
+    fun onlyVisibleItems(): List<ExpandableTreeNode<T>> {
         //Visible if parent of node is expanded.
         return map { it as ExpandableTreeNode }
-            .filter { (it.parent as? ExpandableTreeNode)?.expanded ?: true }
+            .filter { allAncestorsAreExpanded(it) }
+    }
+
+    /**
+     * `Ancestor` is a node reachable by repeated proceeding from child to parent.
+     * @return `True` if parent, and all parent's ancestors are expanded.
+     */
+    private fun allAncestorsAreExpanded(node: ExpandableTreeNode<T>): Boolean {
+        var ancestor = node.parent as? ExpandableTreeNode
+        var ancestorsAreExpanded = isAncestorExpanded(ancestor)
+
+        while (ancestorsAreExpanded && ancestor != null) {
+            ancestor = ancestor.parent as? ExpandableTreeNode<T>
+            ancestorsAreExpanded = ancestorsAreExpanded.and(isAncestorExpanded(ancestor))
+        }
+
+        return ancestorsAreExpanded
+    }
+
+    private fun isAncestorExpanded(ancestor: ExpandableTreeNode<T>?): Boolean {
+        return ancestor?.expanded ?: true
     }
 
 }

expandable-recyclerview/src/main/java/com/github/adriankuta/expandable_recyclerview/ExpandableTreeNodeExt.kt

@@ -6,7 +6,7 @@ import com.github.adriankuta.datastructure.tree.ChildDeclaration
 @JvmSynthetic
 inline fun <reified T> expandableTree(
     value: T,
-    childDeclaration: ChildDeclaration<T>
+    childDeclaration: ChildDeclaration<T> = {}
 ): ExpandableTreeNode<T> {
     val treeNode = ExpandableTreeNode(value)
     treeNode.childDeclaration()

expandable-recyclerview/src/main/res/values/strings.xml

@@ -1,3 +0,0 @@
-<resources>
-    <string name="app_name">Expandable RecyclerView</string>
-</resources>

expandable-recyclerview/src/test/java/com/github/adriankuta/expandable_recyclerview/ExpandableTreeNodeTest.kt

@@ -0,0 +1,24 @@
+package com.github.adriankuta.expandable_recyclerview
+
+import org.junit.Assert
+import org.junit.Test
+
+class ExpandableTreeNodeTest {
+
+    @Test
+    fun getVisibleNode() {
+        //given
+        val root = expandableTree("Root") {
+            child("Level 1") {
+                child("Level 2") {
+                    child("Level 3") {
+                        child("Level 4")
+                    }
+                }
+            }
+        }
+        root.expanded = false
+
+        Assert.assertEquals("Root", root.onlyVisibleItems().first().value)
+    }
+}

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-all.zip

scripts/publish-mavencentral.gradle

@@ -1,122 +0,0 @@
-task androidSourcesJar(type: Jar) {
-    archiveClassifier.set("sources")
-    from android.sourceSets.main.java.source
-}
-
-artifacts {
-    archives androidSourcesJar
-}
-
-apply plugin: 'maven-publish'
-apply plugin: 'signing'
-
-group = PUBLISH_GROUP_ID
-version = PUBLISH_VERSION
-
-ext["signing.keyId"] = ''
-ext["signing.password"] = ''
-ext["signing.secretKeyRingFile"] = ''
-ext["ossrhUsername"] = ''
-ext["ossrhPassword"] = ''
-
-File secretPropsFile = project.rootProject.file('local.properties')
-if (secretPropsFile.exists()) {
-    println "Found secret props file, loading props"
-    Properties p = new Properties()
-    p.load(new FileInputStream(secretPropsFile))
-    p.each { name, value ->
-        ext[name] = value
-    }
-} else {
-    println "No props file, loading env vars"
-    ext["signing.keyId"] = System.getenv('SIGNING_KEY_ID')
-    ext["signing.password"] = System.getenv('SIGNING_PASSWORD')
-    ext["signing.secretKeyRingFile"] = System.getenv('SIGNING_SECRET_KEY_RING_FILE')
-    ext["ossrhUsername"] = System.getenv('OSSRH_USERNAME')
-    ext["ossrhPassword"] = System.getenv('OSSRH_PASSWORD')
-}
-
-nexusStaging {
-    packageGroup = PUBLISH_GROUP_ID
-    stagingProfileId = '2097bad464f778'
-    username = ossrhUsername
-    password = ossrhPassword
-}
-
-publishing {
-    publications {
-        release(MavenPublication) {
-            // The coordinates of the library, being set from variables that
-            // we'll set up in a moment
-            groupId PUBLISH_GROUP_ID
-            artifactId PUBLISH_ARTIFACT_ID
-            version PUBLISH_VERSION
-
-            // Two artifacts, the `aar` and the sources
-            artifact("$buildDir/outputs/aar/${project.getName()}-release.aar")
-            artifact androidSourcesJar
-
-            // Self-explanatory metadata for the most part
-            pom {
-                name = PUBLISH_ARTIFACT_ID
-                description = 'Multilevel expandable recyclerView.'
-                // If your project has a dedicated site, use its URL here
-                url = 'https://github.com/AdrianKuta/Expandable-RecyclerView'
-                licenses {
-                    license {
-                        name = 'Apache License 2.0'
-                        url = 'https://github.com/AdrianKuta/Expandable-RecyclerView/blob/master/LICENSE'
-                    }
-                }
-                developers {
-                    developer {
-                        name = 'Adrian Kuta'
-                        email = 'adrian.kuta93@gmail.com'
-                    }
-                }
-                // Version control info, if you're using GitHub, follow the format as seen here
-                scm {
-                    connection = 'scm:git:github.com/AdrianKuta/Expandable-RecyclerView.git'
-                    developerConnection = 'scm:git:ssh://github.com/AdrianKuta/Expandable-RecyclerView.git'
-                    url = 'https://github.com/AdrianKuta/Expandable-RecyclerView/tree/master'
-                }
-                // A slightly hacky fix so that your POM will include any transitive dependencies
-                // that your library builds upon
-                withXml {
-                    def dependenciesNode = asNode().appendNode('dependencies')
-
-                    project.configurations.implementation.allDependencies.each {
-                        def dependencyNode = dependenciesNode.appendNode('dependency')
-                        dependencyNode.appendNode('groupId', it.group)
-                        dependencyNode.appendNode('artifactId', it.name)
-                        dependencyNode.appendNode('version', it.version)
-                    }
-                }
-            }
-        }
-    }
-    repositories {
-        // The repository to publish to, Sonatype/MavenCentral
-        maven {
-            // This is an arbitrary name, you may also use "mavencentral" or
-            // any other name that's descriptive for you
-            name = "sonatype"
-
-            def releasesRepoUrl = "https://oss.sonatype.org/service/local/staging/deploy/maven2/"
-            def snapshotsRepoUrl = "https://oss.sonatype.org/content/repositories/snapshots/"
-            // You only need this if you want to publish snapshots, otherwise just set the URL
-            // to the release repo directly
-            url = version.endsWith('SNAPSHOT') ? snapshotsRepoUrl : releasesRepoUrl
-
-            // The username and password we've fetched earlier
-            credentials {
-                username ossrhUsername
-                password ossrhPassword
-            }
-        }
-    }
-}
-
-signing {
-    sign publishing.publications
-}

scripts/publish-module.gradle

@@ -0,0 +1,86 @@
+apply plugin: 'maven-publish'
+apply plugin: 'signing'
+apply plugin: 'org.jetbrains.dokka'
+
+task androidSourcesJar(type: Jar) {
+    archiveClassifier.set('sources')
+    if (project.plugins.findPlugin("com.android.library")) {
+        from android.sourceSets.main.java.srcDirs
+        from android.sourceSets.main.kotlin.srcDirs
+    } else {
+        from sourceSets.main.java.srcDirs
+        from sourceSets.main.kotlin.srcDirs
+    }
+}
+
+tasks.withType(dokkaHtmlPartial.getClass()).configureEach {
+    pluginsMapConfiguration.set(
+            ["org.jetbrains.dokka.base.DokkaBase": """{ "separateInheritedMembers": true}"""]
+    )
+}
+
+task javadocJar(type: Jar, dependsOn: dokkaJavadoc) {
+    archiveClassifier.set('javadoc')
+    from dokkaJavadoc.outputDirectory
+}
+
+artifacts {
+    archives androidSourcesJar
+    archives javadocJar
+}
+
+group = PUBLISH_GROUP_ID
+version = PUBLISH_VERSION
+
+afterEvaluate {
+    publishing {
+        publications {
+            release(MavenPublication) {
+                groupId PUBLISH_GROUP_ID
+                artifactId PUBLISH_ARTIFACT_ID
+                version PUBLISH_VERSION
+                if (project.plugins.findPlugin("com.android.library")) {
+                    from components.release
+                } else {
+                    from components.java
+                }
+
+                artifact androidSourcesJar
+                artifact javadocJar
+
+                pom {
+                    name = PUBLISH_ARTIFACT_ID
+                    description = 'Simple implementation to store object in tree structure.'
+                    url = 'https://github.com/AdrianKuta/Tree-Data-Structure'
+                    licenses {
+                        license {
+                            name = 'MIT License'
+                            url = 'https://www.mit.edu/~amini/LICENSE.md'
+                        }
+                    }
+                    developers {
+                        developer {
+                            name = 'Adrian Kuta'
+                            email = 'adrian.kuta93@gmail.com'
+                        }
+                    }
+                    // Version control info, if you're using GitHub, follow the format as seen here
+                    scm {
+                        connection = 'scm:git:github.com/AdrianKuta/Tree-Data-Structure.git'
+                        developerConnection = 'scm:git:ssh://github.com/AdrianKuta/Tree-Data-Structure.git'
+                        url = 'https://github.com/AdrianKuta/Tree-Data-Structure/tree/master'
+                    }
+                }
+            }
+        }
+    }
+}
+
+signing {
+    useInMemoryPgpKeys(
+            rootProject.ext["signing.keyId"],
+            rootProject.ext["signing.key"],
+            rootProject.ext["signing.password"],
+    )
+    sign publishing.publications
+}

scripts/publish-root.gradle

@@ -0,0 +1,43 @@
+// Create variables with empty default values
+ext["ossrhUsername"] = ''
+ext["ossrhPassword"] = ''
+ext["sonatypeStagingProfileId"] = ''
+ext["signing.keyId"] = ''
+ext["signing.password"] = ''
+ext["signing.key"] = ''
+ext["snapshot"] = ''
+
+File secretPropsFile = project.rootProject.file('local.properties')
+if (secretPropsFile.exists()) {
+    // Read local.properties file first if it exists
+    Properties p = new Properties()
+    new FileInputStream(secretPropsFile).withCloseable { is -> p.load(is) }
+    p.each { name, value -> ext[name] = value }
+} else {
+    // Use system environment variables
+    ext["ossrhUsername"] = System.getenv('OSSRH_USERNAME')
+    ext["ossrhPassword"] = System.getenv('OSSRH_PASSWORD')
+    ext["sonatypeStagingProfileId"] = System.getenv('SONATYPE_STAGING_PROFILE_ID')
+    ext["signing.keyId"] = System.getenv('SIGNING_KEY_ID')
+    ext["signing.password"] = System.getenv('SIGNING_PASSWORD')
+    ext["signing.key"] = System.getenv('SIGNING_KEY')
+    ext["snapshot"] = System.getenv('SNAPSHOT')
+}
+
+//if (snapshot) {
+//    ext["rootVersionName"] = Configuration.snapshotVersionName
+//} else {
+//    ext["rootVersionName"] = Configuration.versionName
+//}
+
+// Set up Sonatype repository
+nexusPublishing {
+    repositories {
+        sonatype {
+            stagingProfileId = sonatypeStagingProfileId
+            username = ossrhUsername
+            password = ossrhPassword
+            //version = rootVersionName
+        }
+    }
+}