Week4 recycler view

app/build.gradle

@@ -29,6 +29,7 @@ dependencies {
     implementation 'androidx.core:core-ktx:1.3.1'
     implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+    implementation "androidx.recyclerview:recyclerview:1.1.0"
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test.ext:junit:1.1.1'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'

app/src/main/java/tw/andyang/kotlinandroidworkshop/MainActivity.kt

@@ -1,11 +1,35 @@
 package tw.andyang.kotlinandroidworkshop
 
-import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import androidx.recyclerview.widget.DividerItemDecoration
+import androidx.recyclerview.widget.LinearLayoutManager
+import kotlinx.android.synthetic.main.activity_main.*
 
 class MainActivity : AppCompatActivity() {
+
+    private var todos = listOf<Todo>()
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
+
+        val adapter = TodoAdapter()
+        recyclerView.adapter = adapter
+        recyclerView.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
+        recyclerView.addItemDecoration(DividerItemDecoration(this, LinearLayoutManager.VERTICAL))
+
+        todos = todos.toMutableList().apply {
+            add(Todo.Title(getString(R.string.todo_list_title)))
+        }
+
+        adapter.submitList(todos)
+
+        buttonAdd.setOnClickListener {
+            todos = todos.toMutableList().apply {
+                add(Todo.Item("world", false))
+            }
+            adapter.submitList(todos)
+        }
     }
 }

app/src/main/java/tw/andyang/kotlinandroidworkshop/Todo.kt

@@ -0,0 +1,14 @@
+package tw.andyang.kotlinandroidworkshop
+
+sealed class Todo(val viewType: Int) {
+    data class Title(val text: String) : Todo(TYPE_TITLE)
+    data class Item(
+        val memo: String,
+        val checked: Boolean
+    ) : Todo(TYPE_ITEM)
+
+    companion object {
+        const val TYPE_TITLE = 0
+        const val TYPE_ITEM = 1
+    }
+}

app/src/main/java/tw/andyang/kotlinandroidworkshop/TodoAdapter.kt

@@ -0,0 +1,62 @@
+package tw.andyang.kotlinandroidworkshop
+
+import android.view.LayoutInflater
+import android.view.ViewGroup
+import androidx.appcompat.widget.AppCompatCheckBox
+import androidx.appcompat.widget.AppCompatTextView
+import androidx.recyclerview.widget.DiffUtil
+import androidx.recyclerview.widget.ListAdapter
+import androidx.recyclerview.widget.RecyclerView
+import kotlinx.android.synthetic.main.item_todo.view.*
+
+class TodoAdapter : ListAdapter<Todo, RecyclerView.ViewHolder>(
+    object : DiffUtil.ItemCallback<Todo>() {
+        override fun areItemsTheSame(oldItem: Todo, newItem: Todo): Boolean {
+            return oldItem.viewType == newItem.viewType
+        }
+
+        override fun areContentsTheSame(oldItem: Todo, newItem: Todo): Boolean {
+            return oldItem == newItem
+        }
+    }
+) {
+
+    override fun getItemViewType(position: Int): Int {
+        return getItem(position).viewType
+    }
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
+        return when (viewType) {
+            Todo.TYPE_TITLE -> TodoTitleViewHolder(parent)
+            else -> TodoViewHolder(parent)
+        }
+    }
+
+    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
+        when (val todo = getItem(position)) {
+            is Todo.Title -> (holder as TodoTitleViewHolder).bind(todo)
+            is Todo.Item -> (holder as TodoViewHolder).bind(todo)
+        }
+    }
+}
+
+class TodoViewHolder(parent: ViewGroup) : RecyclerView.ViewHolder(
+    LayoutInflater.from(parent.context).inflate(R.layout.item_todo, parent, false)
+) {
+
+    private val checkbox: AppCompatCheckBox = itemView.checkbox
+
+    fun bind(todo: Todo.Item) {
+        checkbox.text = todo.memo
+        checkbox.isChecked = todo.checked
+    }
+
+}
+
+class TodoTitleViewHolder(parent: ViewGroup) : RecyclerView.ViewHolder(
+    LayoutInflater.from(parent.context).inflate(R.layout.item_title, parent, false)
+) {
+    fun bind(todo: Todo.Title) {
+        (itemView as AppCompatTextView).text = todo.text
+    }
+}

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

@@ -4,15 +4,21 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
+    android:clipToPadding="false"
     tools:context=".MainActivity">
 
-    <TextView
-        android:layout_width="wrap_content"
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/recyclerView"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:paddingBottom="60dp"
+        tools:listitem="@layout/item_todo" />
+
+    <androidx.appcompat.widget.AppCompatButton
+        android:id="@+id/buttonAdd"
+        android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:text="Hello World!"
-        app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintLeft_toLeftOf="parent"
-        app:layout_constraintRight_toRightOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        android:text="@string/add_todo"
+        app:layout_constraintBottom_toBottomOf="parent" />
 
 </androidx.constraintlayout.widget.ConstraintLayout>

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

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.appcompat.widget.AppCompatTextView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:padding="16dp"
+    android:gravity="center"
+    android:text="@string/todo_list_title"
+    android:textColor="#000"
+    android:textSize="26sp" />

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

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:orientation="horizontal"
+    android:padding="16dp">
+
+    <androidx.appcompat.widget.AppCompatCheckBox
+        android:id="@+id/checkbox"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        tools:text="Memo" />
+
+</LinearLayout>

app/src/main/res/values/strings.xml

@@ -1,3 +1,5 @@
 <resources>
     <string name="app_name">KotlinAndroidWorkshop</string>
+    <string name="todo_list_title">備忘錄</string>
+    <string name="add_todo">新增</string>
 </resources>