Generify data binding to view binding

1 files changed, 154 insertions, 0 deletions

diff --git a/fastadapter-viewbinding/src/main/kotlin/ca/allanwang/fastadapter/viewbinding/BindingItem.kt b/fastadapter-viewbinding/src/main/kotlin/ca/allanwang/fastadapter/viewbinding/BindingItem.kt
new file mode 100644
index 0000000..2d1834f
--- /dev/null
+++ b/fastadapter-viewbinding/src/main/kotlin/ca/allanwang/fastadapter/viewbinding/BindingItem.kt
@@ -0,0 +1,154 @@
+/*
+ * Copyright 2019 Allan Wang
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package ca.allanwang.fastadapter.viewbinding
+
+import android.content.Context
+import android.view.View
+import android.view.ViewGroup
+import androidx.recyclerview.widget.RecyclerView
+import androidx.viewbinding.ViewBinding
+import ca.allanwang.kau.fastadapter.databinding.R
+import ca.allanwang.kau.logging.KL
+import com.mikepenz.fastadapter.FastAdapter
+import com.mikepenz.fastadapter.GenericItem
+import com.mikepenz.fastadapter.items.AbstractItem
+import com.mikepenz.fastadapter.listeners.ClickEventHook
+
+interface VhModel {
+    fun vh(): GenericItem
+}
+
+interface BindingLayout<Binding : ViewBinding> {
+    val layoutRes: Int
+    fun createBinding(context: Context, parent: ViewGroup?): Binding
+    fun Binding.bindView(holder: ViewHolder, payloads: MutableList<Any>)
+    fun Binding.unbindView(holder: ViewHolder)
+
+    class ViewHolder(itemView: View, internal val layoutRes: Int) :
+        RecyclerView.ViewHolder(itemView) {
+
+        /**
+         * Retrieves a binding.
+         *
+         * It is assumed that the binding is set on view holder creation,
+         * and that its type matches the supplied generic.
+         */
+        fun <T> getBinding(): T = getBinding(itemView)
+    }
+
+    companion object {
+        fun setBinding(view: View, binding: Any) {
+            view.setTag(R.id.kau_view_binding_model, binding)
+        }
+
+        @Suppress("UNCHECKED_CAST")
+        fun <T> getBinding(view: View): T = view.getTag(R.id.kau_view_binding_model) as T
+    }
+}
+
+abstract class BindingItem<Binding : ViewBinding>(open val data: Any?) :
+    AbstractItem<BindingLayout.ViewHolder>(),
+    BindingLayout<Binding> {
+
+    override val type: Int
+        get() = layoutRes
+
+    override fun createView(ctx: Context, parent: ViewGroup?): View {
+        val binding = createBinding(ctx, parent)
+        BindingLayout.setBinding(binding.root, binding)
+        return binding.root
+    }
+
+    final override fun bindView(holder: BindingLayout.ViewHolder, payloads: MutableList<Any>) {
+        super.bindView(holder, payloads)
+        val binding = holder.getBinding<Binding>()
+        binding.bindView(holder, payloads)
+    }
+
+    final override fun unbindView(holder: BindingLayout.ViewHolder) {
+        super.unbindView(holder)
+        val binding = holder.getBinding<Binding>()
+        binding.unbindView(holder)
+    }
+
+    override fun Binding.unbindView(holder: BindingLayout.ViewHolder) {}
+
+    final override fun getViewHolder(v: View): BindingLayout.ViewHolder =
+        BindingLayout.ViewHolder(v, layoutRes)
+
+    override fun failedToRecycle(holder: BindingLayout.ViewHolder): Boolean {
+        KL.e { "Failed to recycle" }
+        return super.failedToRecycle(holder)
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is BindingItem<*>) return false
+        return identifier == other.identifier && data == other.data
+    }
+
+    override fun hashCode(): Int = data.hashCode()
+}
+
+abstract class BindingClickEventHook<Binding : ViewBinding, Item : BindingItem<Binding>>(val identifier: BindingLayout<Binding>) :
+    ClickEventHook<Item>() {
+
+    private fun RecyclerView.ViewHolder.binding(): Binding? {
+        val holder = this as? BindingLayout.ViewHolder ?: return null
+        if (holder.layoutRes != identifier.layoutRes) {
+            return null
+        }
+        return getBinding()
+    }
+
+    /**
+     * All bound views must set the view root, which will be used to find the binding.
+     * We avoid attaching the binding directly
+     */
+    private fun View.setRoot(root: View) {
+        setTag(R.id.kau_view_binding_root, root)
+    }
+
+    private fun View.findBinding(): Binding {
+        val root = getTag(R.id.kau_view_binding_root) as View
+        return BindingLayout.getBinding(root)
+    }
+
+    final override fun onBind(viewHolder: RecyclerView.ViewHolder): View? {
+        val binding = viewHolder.binding() ?: return super.onBind(viewHolder)
+        val view = binding.onBind(viewHolder) ?: return super.onBind(viewHolder)
+        view.setRoot(binding.root)
+        return view
+    }
+
+    open fun Binding.onBind(viewHolder: RecyclerView.ViewHolder): View? = super.onBind(viewHolder)
+
+    final override fun onBindMany(viewHolder: RecyclerView.ViewHolder): List<View>? {
+        val binding = viewHolder.binding() ?: return super.onBindMany(viewHolder)
+        val views = binding.onBindMany(viewHolder) ?: return super.onBindMany(viewHolder)
+        views.forEach { it.setRoot(binding.root) }
+        return views
+    }
+
+    open fun Binding.onBindMany(viewHolder: RecyclerView.ViewHolder): List<View>? =
+        super.onBindMany(viewHolder)
+
+    final override fun onClick(v: View, position: Int, fastAdapter: FastAdapter<Item>, item: Item) {
+        v.findBinding().onClick(v, position, fastAdapter, item)
+    }
+
+    abstract fun Binding.onClick(v: View, position: Int, fastAdapter: FastAdapter<Item>, item: Item)
+}