Add binding paging adapter

buildSrc/src/main/kotlin/Dependencies.kt

@@ -46,6 +46,7 @@ object Dependencies {
         const val viewPager2 = "androidx.viewpager2:viewpager2:${Versions.viewPager2}"
         const val databinding = "androidx.databinding:databinding-runtime:${Versions.databinding}"
         const val material = "com.google.android.material:material:${Versions.material}"
+        const val paging = "androidx.paging:paging-runtime:${Versions.paging}"
     }
 
     /* =============================  TEST ================================ */

buildSrc/src/main/kotlin/Versions.kt

@@ -1,3 +1,4 @@
+
 object Versions {
     const val gradle = "7.1"
     const val gradleBuildTools = "4.2.0"
@@ -14,7 +15,7 @@ object Versions {
     const val viewPager2 = "1.0.0"
     const val databinding = "4.2.1"
     const val material = "1.3.0"
-
+    const val paging = "3.0.0"
     const val retrofit = "2.9.0"
 
     const val timber = "4.7.1"

kaal-core/build.gradle.kts

@@ -1,5 +1,3 @@
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
-
 plugins {
     id("com.android.library")
     kotlin("android")
@@ -42,6 +40,10 @@ android {
 
     }
 
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+
     lintOptions {
         lintConfig = rootProject.file("lint.xml")
     }
@@ -56,12 +58,6 @@ dependencies {
     testImplementation(Dependencies.Test.kotlinTest)
 }
 
-tasks.withType<KotlinCompile> {
-    kotlinOptions {
-        jvmTarget = "1.8"
-    }
-}
-
 tasks.dokkaHtml.configure {
     moduleName.set("kaal-core")
     outputDirectory.set(buildDir.resolve("dokka/html"))

kaal-domain/build.gradle.kts

@@ -1,4 +1,3 @@
-import org.jetbrains.dokka.gradle.DokkaTask
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {

kaal-infrastructure/build.gradle.kts

@@ -1,5 +1,3 @@
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
-
 plugins {
     id("com.android.library")
     kotlin("android")
@@ -41,6 +39,10 @@ android {
         targetCompatibility = Android.targetCompatibilityJava
     }
 
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+
     lintOptions {
         lintConfig = rootProject.file("lint.xml")
     }
@@ -65,12 +67,6 @@ dependencies {
     testImplementation(Dependencies.Test.kotlinTest)
 }
 
-tasks.withType<KotlinCompile> {
-    kotlinOptions {
-        jvmTarget = "1.8"
-    }
-}
-
 tasks.dokkaHtml.configure {
     moduleName.set("kaal-infrastructure")
     outputDirectory.set(buildDir.resolve("dokka/html"))

kaal-presentation/build.gradle.kts

@@ -1,5 +1,3 @@
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
-
 plugins {
     id("com.android.library")
     kotlin("android")
@@ -40,7 +38,10 @@ android {
     compileOptions {
         sourceCompatibility = Android.sourceCompatibilityJava
         targetCompatibility = Android.targetCompatibilityJava
+    }
 
+    kotlinOptions {
+        jvmTarget = "1.8"
     }
 
     lintOptions {
@@ -52,12 +53,6 @@ android {
     }
 }
 
-tasks.withType<KotlinCompile> {
-    kotlinOptions {
-        jvmTarget = "1.8"
-    }
-}
-
 dependencies {
     api(project(":kaal-domain"))
 
@@ -73,6 +68,7 @@ dependencies {
     compileOnly(Dependencies.Android.material)
     compileOnly(Dependencies.Android.recyclerView)
     compileOnly(Dependencies.Android.viewPager2)
+    compileOnly(Dependencies.Android.paging)
 
     // Timber
     implementation(Dependencies.timber)

kaal-presentation/src/main/kotlin/cz/eman/kaal/presentation/adapter/BaseBindingAdapter.kt

@@ -0,0 +1,213 @@
+package cz.eman.kaal.presentation.adapter
+
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.annotation.IntRange
+import androidx.annotation.LayoutRes
+import androidx.annotation.MainThread
+import androidx.databinding.DataBindingUtil
+import androidx.databinding.ViewDataBinding
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleOwner
+import androidx.lifecycle.LifecycleRegistry
+import androidx.recyclerview.widget.RecyclerView
+import cz.eman.kaal.presentation.R
+import cz.eman.kaal.presentation.adapter.binder.ItemBinder
+import cz.eman.kaal.presentation.adapter.binder.VariableBinder
+
+/**
+ * Handles basic (common) functionality for Binding adapters. Takes care of view creation, data binding, click listeners
+ * and other common functionality for adapters.
+ *
+ * This is an interface due to different parents for adapters. It requires access to multiple variables from the
+ * extending classes like [itemBinder], [itemClickListener], and others. Prevents code being repeated but it also makes
+ * the variables public.
+ *
+ * @property T type of the object handled by this interface
+ * @author eMan a.s.
+ * @author Radek Piekarz
+ * @see [GitHub project](https://github.com/radzio/android-data-binding-recyclerview)
+ * @see BaseBindingAdapter
+ * @since 0.9.0
+ */
+@Suppress("UNCHECKED_CAST")
+interface BaseBindingAdapter<T : Any> : View.OnClickListener,
+    View.OnLongClickListener {
+
+    /**
+     * Gets item on a specific position in the adapter. Must be implemented by extending class.
+     *
+     * @param position of the item
+     * @return [T] item or null when not found
+     */
+    fun getItemInternal(@IntRange(from = 0) position: Int): T?
+
+    /**
+     * Item binder specifies binding layout for specific item. For more information check [ItemBinder].
+     */
+    val itemBinder: ItemBinder<T>
+
+    /**
+     * Specifies click action for the whole item layout ([ViewHolder]). Click on any sub-view of the holder must be
+     * handled separately. Ex: you can send ViewModel using [variableBinders] and bind click directly in layout xml.
+     */
+    val itemClickListener: ((View, T) -> Unit)?
+
+    /**
+     * Same as the [itemClickListener] with the exception that it handles long click instead of click.
+     */
+    val itemLongClickListener: ((View, T) -> Unit)?
+
+    /**
+     * Used to send custom variables to item layout [ViewHolder]. Any variable can be send but most common is ViewModel.
+     * For more information check [VariableBinder].
+     */
+    val variableBinders: Array<VariableBinder<T>>?
+
+    /**
+     * Creates instance of [ViewHolder] with specific binding layout inflated using [layoutId].
+     *
+     * @param viewGroup for the layout inflation
+     * @param layoutId layout resource identifying which layout should be inflated
+     * @return inflated [ViewHolder]
+     * @see ViewHolder
+     * @see DataBindingUtil.inflate
+     */
+    fun onCreateViewHolderInternal(viewGroup: ViewGroup, @LayoutRes layoutId: Int): ViewHolder {
+        return ViewHolder(DataBindingUtil.inflate(LayoutInflater.from(viewGroup.context), layoutId, viewGroup, false))
+    }
+
+    /**
+     * Binds item data to the [ViewHolder]. Gets the specific item (if possible) and sets it to the view holder binding.
+     * It also sets any other variables from [variableBinders] binds click listeners (if they are enabled).
+     *
+     * Since [ViewHolder] allows variable observing using [Lifecycle] it will set the binding [LifecycleOwner] as a
+     * [ViewHolder]. It makes sure all variable changes are propagated to the binding. After binding is configured it
+     * also triggers [ViewDataBinding.executePendingBindings] to make sure all displayed information correspond with the
+     * item information.
+     *
+     * @param viewHolder to have variables and listeners set
+     * @param position of the item in the list
+     * @see ViewDataBinding.setVariable
+     * @see ViewDataBinding.executePendingBindings
+     */
+    fun onBindViewHolderInternal(viewHolder: ViewHolder, position: Int) {
+        val item = getItemInternal(position) ?: return
+        viewHolder.binding.apply {
+            lifecycleOwner = viewHolder
+
+            setVariable(itemBinder.getBindingVariable(item), item)
+            variableBinders?.forEach {
+                setVariable(
+                    it.getVariableId(item),
+                    it.getVariableValue(item)
+                )
+            }
+        }.executePendingBindings()
+
+        viewHolder.binding.root.apply {
+            setTag(R.id.recycler_view_adapter_item_model, item)
+            // Must be like this to keep the original value
+            isClickable = isClickable.also { setOnClickListener(this@BaseBindingAdapter) }
+            isLongClickable = isLongClickable.also { setOnLongClickListener(this@BaseBindingAdapter) }
+        }
+    }
+
+    /**
+     * When view is attached to the window the [ViewHolder] starts observing variables.
+     *
+     * @param viewHolder to start listening in
+     * @see ViewHolder.onStart
+     */
+    fun onViewAttachedToWindowInternal(viewHolder: ViewHolder) {
+        viewHolder.onStart()
+    }
+
+    /**
+     * When view is detached from the window the [ViewHolder] stops observing variables.
+     *
+     * @param viewHolder to start listening in
+     * @see ViewHolder.onStop
+     */
+    fun onViewDetachedFromWindowInternal(viewHolder: ViewHolder) {
+        viewHolder.onStop()
+    }
+
+    /**
+     * Gets item view type by it's [position]. Gets the item using [getItemInternal] and then it gets layout resource
+     * for it from the [itemBinder]. If it is not found then 0 is returned.
+     *
+     * @param position of the item in the list
+     * @return [Int] with layout resource
+     * @see getItemInternal
+     * @see ItemBinder.getLayoutRes
+     */
+    @LayoutRes
+    fun getItemViewTypeInternal(position: Int) =
+        getItemInternal(position)?.let { itemBinder.getLayoutRes(it) } ?: 0
+
+    /**
+     * Handles click on the item view by getting the item from view tag and invoking [itemClickListener] if it exists.
+     *
+     * @param view used to get the item and also being send to the click listener
+     */
+    override fun onClick(view: View) {
+        itemClickListener?.let {
+            val item = view.getTag(R.id.recycler_view_adapter_item_model) as T
+            it.invoke(view, item)
+        }
+    }
+
+    /**
+     * Handles long click on the item view by getting the item from view tag and invoking [itemLongClickListener] if it
+     * exists.
+     *
+     * @param view used to get the item and also being send to the click listener
+     * @return true if handled by the [itemLongClickListener] else false
+     */
+    override fun onLongClick(view: View): Boolean {
+        return itemLongClickListener?.let {
+            val item = view.getTag(R.id.recycler_view_adapter_item_model) as T
+            it.invoke(view, item)
+            true
+        } ?: false
+    }
+
+    /**
+     * View holder for the [RecyclerView.Adapter] holding [ViewDataBinding] for the item and also serving as a
+     * [LifecycleOwner] to listen for any changes in lifecycle events.
+     *
+     * @property binding view binding for the holder
+     * @see RecyclerView.ViewHolder
+     */
+    class ViewHolder(val binding: ViewDataBinding) : RecyclerView.ViewHolder(binding.root),
+        LifecycleOwner {
+
+        /**
+         * @see LifecycleRegistry
+         */
+        private val registry: LifecycleRegistry = LifecycleRegistry(this)
+
+        /**
+         * @see LifecycleOwner.getLifecycle
+         */
+        override fun getLifecycle(): Lifecycle = registry
+
+        /**
+         * Sets [Lifecycle.Event.ON_START] event to the [registry] to start observing variable changes.
+         */
+        @MainThread
+        fun onStart() {
+            registry.handleLifecycleEvent(Lifecycle.Event.ON_START)
+        }
+
+        /**
+         * Sets [Lifecycle.Event.ON_STOP] event to the [registry] to stop observing variable changes.
+         */
+        @MainThread
+        fun onStop() {
+            registry.handleLifecycleEvent(Lifecycle.Event.ON_STOP)
+        }
+    }
+}

kaal-presentation/src/main/kotlin/cz/eman/kaal/presentation/adapter/BindingAdapterConfig.kt

@@ -0,0 +1,28 @@
+package cz.eman.kaal.presentation.adapter
+
+import android.view.View
+import androidx.recyclerview.widget.DiffUtil
+import cz.eman.kaal.presentation.adapter.binder.ItemBinder
+import cz.eman.kaal.presentation.adapter.binder.VariableBinder
+
+/**
+ * Wrapper data class for Binding adapter configuration. It is used when binding adapter is being created. Holds only
+ * common information and all extending information must be handled separately.
+ *
+ * @property itemBinder defines layout for specific item types
+ * @property variableBinders allows sending custom variables to the layout
+ * @property itemClickListener enables to handle item click (not sub-view click)
+ * @property itemLongClickListener enables to handle item long click (not sub-view click)
+ * @property limit of how many items can be displayed
+ * @property differ used to compare items
+ * @author: eMan a.s.
+ * @since 0.9.0
+ */
+class BindingAdapterConfig<T : Any>(
+    val itemBinder: ItemBinder<T>,
+    val variableBinders: Array<VariableBinder<T>>?,
+    val itemClickListener: ((View, T) -> Unit)?,
+    val itemLongClickListener: ((View, T) -> Unit)?,
+    val limit: Int? = null,
+    val differ: DiffUtil.ItemCallback<T>? = null
+)