Week8 storage

app/build.gradle

@@ -1,6 +1,7 @@
 apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
+apply plugin: "kotlin-kapt"
 apply plugin: "androidx.navigation.safeargs.kotlin"
 
 android {
@@ -51,4 +52,16 @@ dependencies {
     androidTestImplementation 'androidx.test.ext:junit:1.1.1'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
 
+
+    /*** Room Dependencies Start ***/
+    def room_version = "2.2.5"
+    implementation "androidx.room:room-runtime:$room_version"
+    kapt "androidx.room:room-compiler:$room_version"
+
+    // optional - Kotlin Extensions and Coroutines support for Room
+    implementation "androidx.room:room-ktx:$room_version"
+
+    // optional - Test helpers
+    testImplementation "androidx.room:room-testing:$room_version"
+    /*** Room Dependencies End ***/
 }

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

@@ -11,6 +11,9 @@ import androidx.lifecycle.ViewModelProvider
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.fragment.navArgs
 import kotlinx.android.synthetic.main.fragment_add_todo.*
+import tw.andyang.kotlinandroidworkshop.database.AppDatabase
+import tw.andyang.kotlinandroidworkshop.mvvm.AnyViewModelFactory
+import tw.andyang.kotlinandroidworkshop.repository.TodoItemRepository
 
 class AddTodoFragment : Fragment() {
 
@@ -40,7 +43,12 @@ class AddTodoFragment : Fragment() {
         editTodo.setText(args.memo)
         editTodo.setSelection(args.memo.length)
 
-        val todoViewModel = ViewModelProvider(requireActivity()).get(TodoViewModel::class.java)
+        val todoItemDb = AppDatabase.getInstance(requireActivity().applicationContext)
+        val todoItemRepo = TodoItemRepository(todoItemDb)
+        val viewModelFactory = AnyViewModelFactory {
+            TodoViewModel(todoItemRepo)
+        }
+        val todoViewModel = ViewModelProvider(requireActivity(), viewModelFactory).get(TodoViewModel::class.java)
 
         buttonAdd.setOnClickListener {
             if (editTodo.text.isNullOrEmpty()) {
@@ -49,7 +57,8 @@ class AddTodoFragment : Fragment() {
                 // clear error
                 editTodo.error = null
                 // post data to view model
-                todoViewModel.onNewTodo.postValue(editTodo.text.toString())
+                val title = editTodo.text.toString()
+                todoViewModel.createNewTodo(title)
                 // hide soft keyboard when item added
                 view.clearFocus()
                 inputMethodManager.hideSoftInputFromWindow(view.windowToken, 0)

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

@@ -0,0 +1,5 @@
+package tw.andyang.kotlinandroidworkshop
+
+interface OnTodoChangeListener {
+    fun onChange(todo: Todo.Item)
+}

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

@@ -1,10 +1,14 @@
 package tw.andyang.kotlinandroidworkshop
 
+import java.util.*
+
 sealed class Todo(val viewType: Int) {
     data class Title(val text: String) : Todo(TYPE_TITLE)
     data class Item(
+        val id: Int,
         val memo: String,
-        val checked: Boolean
+        val checked: Boolean,
+        val createdAt: Date
     ) : Todo(TYPE_ITEM)
 
     companion object {

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

@@ -8,6 +8,7 @@ import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ListAdapter
 import androidx.recyclerview.widget.RecyclerView
 import kotlinx.android.synthetic.main.item_todo.view.*
+import java.text.SimpleDateFormat
 
 class TodoAdapter : ListAdapter<Todo, RecyclerView.ViewHolder>(
     object : DiffUtil.ItemCallback<Todo>() {
@@ -21,14 +22,16 @@ class TodoAdapter : ListAdapter<Todo, RecyclerView.ViewHolder>(
     }
 ) {
 
+    var onTodoChangeListener: OnTodoChangeListener? = null
+
     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)
+            else -> TodoViewHolder(parent, onTodoChangeListener)
         }
     }
 
@@ -40,15 +43,21 @@ class TodoAdapter : ListAdapter<Todo, RecyclerView.ViewHolder>(
     }
 }
 
-class TodoViewHolder(parent: ViewGroup) : RecyclerView.ViewHolder(
+class TodoViewHolder(parent: ViewGroup, private val onTodoChangeListener: OnTodoChangeListener?) : RecyclerView.ViewHolder(
     LayoutInflater.from(parent.context).inflate(R.layout.item_todo, parent, false)
 ) {
 
     private val checkbox: AppCompatCheckBox = itemView.checkbox
+    private val date = itemView.create_at
 
     fun bind(todo: Todo.Item) {
         checkbox.text = todo.memo
         checkbox.isChecked = todo.checked
+        checkbox.setOnClickListener { view ->
+            onTodoChangeListener?.onChange(Todo.Item(todo.id, todo.memo, !todo.checked, todo.createdAt))
+        }
+
+        date.text = SimpleDateFormat.getDateTimeInstance().format(todo.createdAt)
     }
 
 }

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

@@ -11,6 +11,9 @@ import androidx.navigation.fragment.findNavController
 import androidx.recyclerview.widget.DividerItemDecoration
 import androidx.recyclerview.widget.LinearLayoutManager
 import kotlinx.android.synthetic.main.fragment_todo_list.*
+import tw.andyang.kotlinandroidworkshop.database.AppDatabase
+import tw.andyang.kotlinandroidworkshop.mvvm.AnyViewModelFactory
+import tw.andyang.kotlinandroidworkshop.repository.TodoItemRepository
 
 class TodoListFragment : Fragment() {
 
@@ -25,7 +28,20 @@ class TodoListFragment : Fragment() {
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
 
-        val adapter = TodoAdapter()
+        val todoItemDb = AppDatabase.getInstance(requireActivity().applicationContext)
+        val todoItemRepo = TodoItemRepository(todoItemDb)
+        val viewModelFactory = AnyViewModelFactory {
+            TodoViewModel(todoItemRepo)
+        }
+        val todoViewModel = ViewModelProvider(requireActivity(), viewModelFactory).get(TodoViewModel::class.java)
+
+        val adapter = TodoAdapter().apply {
+            onTodoChangeListener = object : OnTodoChangeListener {
+                override fun onChange(todo: Todo.Item) {
+                    todoViewModel.updateTodo(todo)
+                }
+            }
+        }
         recyclerView.adapter = adapter
         recyclerView.layoutManager =
             LinearLayoutManager(requireContext(), LinearLayoutManager.VERTICAL, false)
@@ -36,8 +52,6 @@ class TodoListFragment : Fragment() {
             )
         )
 
-        val todoViewModel = ViewModelProvider(requireActivity()).get(TodoViewModel::class.java)
-
         todoViewModel.todoLiveData.observe(viewLifecycleOwner, Observer { todos: List<Todo> ->
             adapter.submitList(todos)
         })

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

@@ -1,19 +1,52 @@
 package tw.andyang.kotlinandroidworkshop
 
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.MediatorLiveData
-import androidx.lifecycle.MutableLiveData
-import androidx.lifecycle.ViewModel
+import androidx.lifecycle.*
+import kotlinx.coroutines.launch
+import tw.andyang.kotlinandroidworkshop.database.TodoItem
+import tw.andyang.kotlinandroidworkshop.repository.TodoItemRepository
+import java.util.*
 
-class TodoViewModel : ViewModel() {
+class TodoViewModel(private val repository: TodoItemRepository) : ViewModel() {
 
-    val onNewTodo = MutableLiveData<String>()
+    private val title = Todo.Title("This is a title")
 
     val todoLiveData: LiveData<List<Todo>> = MediatorLiveData<List<Todo>>().apply {
-        addSource(onNewTodo) { text ->
-            val todo = Todo.Item(text, false)
-            this.value = this.value!! + listOf(todo)
+        val source = repository.getTodoItems().map {
+            it.map { todoItem ->
+                Todo.Item(
+                    todoItem.id,
+                    todoItem.title,
+                    todoItem.done,
+                    todoItem.createdAt
+                )
+            }
+        }
+        addSource(source) {
+            this.value = mutableListOf(title) + it
+        }
+        value = mutableListOf(title)
+    }
+
+    fun createNewTodo(title: String) {
+        val todoItem = TodoItem(
+            title = title,
+            done = false,
+            createdAt = Date()
+        )
+        viewModelScope.launch {
+            repository.insertTodoItem(todoItem)
+        }
+    }
+
+    fun updateTodo(todo: Todo.Item) {
+        val todoItem = TodoItem(
+            title = todo.memo,
+            done = todo.checked,
+            createdAt = todo.createdAt
+        ).apply { id = todo.id }
+
+        viewModelScope.launch {
+            repository.updateTodoItem(todoItem)
         }
-        value = mutableListOf(Todo.Title("This is a title"))
     }
 }

app/src/main/java/tw/andyang/kotlinandroidworkshop/database/AppDatabase.kt

@@ -0,0 +1,36 @@
+package tw.andyang.kotlinandroidworkshop.database
+
+import android.content.Context
+import androidx.room.Database
+import androidx.room.Room
+import androidx.room.RoomDatabase
+import androidx.room.TypeConverters
+
+@Database(
+    version = 1,
+    entities = [
+        TodoItem::class
+    ],
+    exportSchema = false
+)
+@TypeConverters(Converters::class)
+abstract class AppDatabase: RoomDatabase() {
+    companion object {
+        private const val DATABASE_NAME = "todo_list_db"
+
+        // For Singleton instantiation
+        @Volatile private var instance: AppDatabase? = null
+
+        fun getInstance(context: Context): AppDatabase {
+            return instance ?: synchronized(this) {
+                instance ?: buildDatabase(context).also { instance = it }
+            }
+        }
+
+        private fun buildDatabase(context: Context): AppDatabase {
+            return Room.databaseBuilder(context, AppDatabase::class.java, DATABASE_NAME).build()
+        }
+    }
+
+    abstract fun todoItemDao(): TodoItemDao
+}

app/src/main/java/tw/andyang/kotlinandroidworkshop/database/Converters.kt

@@ -0,0 +1,16 @@
+package tw.andyang.kotlinandroidworkshop.database
+
+import androidx.room.TypeConverter
+import java.util.*
+
+class Converters {
+    @TypeConverter
+    fun fromTimestamp(value: Long?): Date? {
+        return value?.let { Date(it) }
+    }
+
+    @TypeConverter
+    fun dateToTimestamp(date: Date?): Long? {
+        return date?.time
+    }
+}

app/src/main/java/tw/andyang/kotlinandroidworkshop/database/GenericDao.kt

@@ -0,0 +1,40 @@
+package tw.andyang.kotlinandroidworkshop.database
+
+import androidx.room.Delete
+import androidx.room.Insert
+import androidx.room.Update
+
+interface GenericDao<T> {
+
+    /**
+     * Insert an object in the database.
+     *
+     * @param obj the object to be inserted.
+     */
+    @Insert
+    suspend fun insert(obj: T)
+
+    /**
+     * Insert an array of objects in the database.
+     *
+     * @param obj the objects to be inserted.
+     */
+    @Insert
+    suspend fun insert(vararg obj: T)
+
+    /**
+     * Update an object from the database.
+     *
+     * @param obj the object to be updated
+     */
+    @Update
+    suspend fun update(obj: T)
+
+    /**
+     * Delete an object from the database
+     *
+     * @param obj the object to be deleted
+     */
+    @Delete
+    suspend fun delete(obj: T)
+}

app/src/main/java/tw/andyang/kotlinandroidworkshop/database/TodoItem.kt

@@ -0,0 +1,26 @@
+package tw.andyang.kotlinandroidworkshop.database
+
+import androidx.room.*
+import java.util.*
+
+@Entity(
+    tableName = TodoItem.TABLE_NAME
+)
+data class TodoItem (
+    @ColumnInfo(name = COLUMN_TITLE) var title: String,
+    @ColumnInfo(name = COLUMN_DONE) var done: Boolean,
+    @ColumnInfo(name = COLUMN_CREATED_AT) var createdAt: Date
+) {
+    companion object {
+        const val TABLE_NAME = "todo_items"
+
+        const val COLUMN_ID = "id"
+        const val COLUMN_TITLE = "title"
+        const val COLUMN_DONE = "done"
+        const val COLUMN_CREATED_AT = "created_at"
+    }
+
+    // 必須為 var 才會有 setter
+    @PrimaryKey(autoGenerate = true)
+    @ColumnInfo(name = COLUMN_ID) var id: Int = 0
+}

app/src/main/java/tw/andyang/kotlinandroidworkshop/database/TodoItemDao.kt

@@ -0,0 +1,12 @@
+package tw.andyang.kotlinandroidworkshop.database
+
+import androidx.lifecycle.LiveData
+import androidx.room.Dao
+import androidx.room.Query
+
+@Dao
+interface TodoItemDao: GenericDao<TodoItem> {
+
+    @Query("SELECT * FROM ${TodoItem.TABLE_NAME} ORDER BY ${TodoItem.COLUMN_CREATED_AT} DESC")
+    fun findAll(): LiveData<List<TodoItem>>
+}

app/src/main/java/tw/andyang/kotlinandroidworkshop/mvvm/AnyViewModelFactory.kt

@@ -0,0 +1,12 @@
+package tw.andyang.kotlinandroidworkshop.mvvm
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+
+class AnyViewModelFactory<T : ViewModel?>(val creator: () -> T) : ViewModelProvider.Factory {
+
+    override fun <T : ViewModel?> create(modelClass: Class<T>): T {
+        return creator() as T
+    }
+
+}