102 learning resources

app/build.gradle

@@ -34,6 +34,11 @@ android {
     testOptions {
         unitTests.returnDefaultValues = true
     }
+
+    dataBinding {
+        // https://developer.android.com/topic/libraries/data-binding/start
+        enabled = true
+    }
 }
 
 dependencies {

app/src/main/java/com/hossainkhan/android/demo/ui/common/DataBoundListAdapter.kt

@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2019 Hossain Khan
+ *
+ * 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 com.hossainkhan.android.demo.ui.common
+
+import android.view.ViewGroup
+import androidx.databinding.ViewDataBinding
+import androidx.recyclerview.widget.AsyncDifferConfig
+import androidx.recyclerview.widget.DiffUtil
+import androidx.recyclerview.widget.ListAdapter
+
+/**
+ * A generic RecyclerView adapter that uses Data Binding & DiffUtil.
+ *
+ * Here is an example of adapter with diff utils and click listener implemented.
+ * ```kotlin
+ * class ExampleListAdapter(
+ *     private val itemClickCallback: ((ModelObject) -> Unit)?
+ * ) : DataBoundListAdapter<ModelObject, ListItemBinding>(
+ *     diffCallback = object : DiffUtil.ItemCallback<ModelObject>() {
+ *         override fun areItemsTheSame(oldItem: ModelObject, newItem: ModelObject): Boolean {
+ *             return oldItem.id == newItem.id
+ *         }
+ *
+ *         override fun areContentsTheSame(oldItem: ModelObject, newItem: ModelObject): Boolean {
+ *             return oldItem == newItem
+ *         }
+ *     }
+ * ) {
+ *
+ *     override fun createBinding(parent: ViewGroup): ListItemBinding {
+ *         val binding = DataBindingUtil.inflate<ListItemBinding>(
+ *             LayoutInflater.from(parent.context), R.layout.list_item,
+ *             parent, false)
+ *
+ *         binding.root.setOnClickListener {
+ *             binding.data?.let {
+ *                 itemClickCallback?.invoke(it)
+ *             }
+ *         }
+ *         return binding
+ *     }
+ *
+ *     override fun bind(binding: ListItemBinding, item: ModelObject) {
+ *         binding.idea = item
+ *     }
+ * }
+ * ```
+ *
+ * And here is how the adapter is instantiated in Fragment/Activity
+ * ```
+ * val ideaListAdapter = ExampleListAdapter { modelObject ->
+ *     doActionOnModelObjectSelected(modelObject)
+ * }
+ * ```
+ *
+ * @param <T> Type of the items in the list
+ * @param <V> The type of the ViewDataBinding
+ */
+abstract class DataBoundListAdapter<T, V : ViewDataBinding>(
+    diffCallback: DiffUtil.ItemCallback<T>
+) : ListAdapter<T, DataBoundViewHolder<V>>(
+    AsyncDifferConfig.Builder<T>(diffCallback).build()
+) {
+    /**
+     * Provides [ViewDataBinding] for the list item after it's inflated with DataBinding.
+     */
+    protected abstract fun createBinding(parent: ViewGroup): V
+
+    /**
+     * API where view should bound with the data model item.
+     */
+    protected abstract fun bind(binding: V, item: T)
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DataBoundViewHolder<V> {
+        val binding = createBinding(parent)
+        return DataBoundViewHolder(binding)
+    }
+
+
+    override fun onBindViewHolder(holder: DataBoundViewHolder<V>, position: Int) {
+        bind(holder.binding, getItem(position))
+        holder.binding.executePendingBindings()
+    }
+
+
+}

app/src/main/java/com/hossainkhan/android/demo/ui/common/DataBoundViewHolder.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2019 Hossain Khan
+ *
+ * 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 com.hossainkhan.android.demo.ui.common
+
+import androidx.databinding.ViewDataBinding
+import androidx.recyclerview.widget.RecyclerView
+
+/**
+ * A generic ViewHolder that works with a [ViewDataBinding].
+ * @param <T> The type of the ViewDataBinding.
+ */
+class DataBoundViewHolder<out T : ViewDataBinding> constructor(
+    val binding: T
+) : RecyclerView.ViewHolder(binding.root)