Issue #37: Data Binding on Characters Activity

data/src/main/java/com/architect/coders/mu8/data/DataApp.kt

@@ -15,6 +15,8 @@ open class DataApp : Application() {
  this,
  MU8Database::class.java,
  "MU8-db"
- ).build()
+ )
+ .fallbackToDestructiveMigration()
+ .build()
  }
 }

data/src/main/java/com/architect/coders/mu8/data/database/MU8Database.kt

@@ -9,7 +9,7 @@ import com.architect.coders.mu8.data.database.converter.ListStringTypeConverters
 import com.architect.coders.mu8.data.database.converter.ThumbnailTypeConverters
 import com.architect.coders.mu8.data.database.converter.UrlsTypeConverters
 
-private const val DATABASE_VERSION = 1
+private const val DATABASE_VERSION = 2
 
 @Database(entities = [CharactersEntity::class], version = DATABASE_VERSION)
 @TypeConverters(UrlsTypeConverters::class, ThumbnailTypeConverters::class, ListStringTypeConverters::class)

data/src/main/java/com/architect/coders/mu8/data/service/MarvelServiceAPI.kt

@@ -45,4 +45,4 @@ interface MarvelServiceAPI {
  @Query(OFFSET) offset: Int,
  @Query(LIMIT) limit: Int
  ): Response<BaseResponse<EventsResponse>>
-}
+}

domain/src/main/java/com/architect/codes/mu8/characters/Character.kt

@@ -9,4 +9,4 @@ data class Character(
  val thumbnailUrl: String,
  val urls: List<Urls> = emptyList(),
  val comicIds: List<String> = emptyList()
-)
+)

presentation/build.gradle

@@ -3,6 +3,7 @@ apply plugin: 'com.google.gms.google-services'
 apply plugin: 'io.fabric'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-kapt'
 apply from: "$rootDir/detekt.gradle"
 
 android {
@@ -23,6 +24,9 @@ android {
  proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
  }
  }
+ dataBinding{
+ enabled true
+ }
 }
 
 dependencies {

presentation/src/main/java/com/architect/coders/mu8/characters/CharactersActivity.kt

@@ -1,63 +1,59 @@
 package com.architect.coders.mu8.characters
 
 import android.os.Bundle
-import android.view.View.GONE
-import android.view.View.VISIBLE
-import android.widget.ProgressBar
-import android.widget.TextView
 import androidx.appcompat.app.AppCompatActivity
-import androidx.appcompat.widget.Toolbar
+import androidx.databinding.DataBindingUtil
 import androidx.lifecycle.Observer
 import androidx.recyclerview.widget.LinearLayoutManager
-import androidx.recyclerview.widget.RecyclerView
 import com.architect.coders.mu8.R
-import com.architect.coders.mu8.characters.CharactersUiModel.Content
-import com.architect.coders.mu8.characters.CharactersUiModel.Loading
-import com.architect.coders.mu8.characters.CharactersUiModel.Navigation
 import com.architect.coders.mu8.characters.detail.CharactersDetailActivity
 import com.architect.coders.mu8.data.DataApp
 import com.architect.coders.mu8.data.characters.CharactersRepositoryImpl
+import com.architect.coders.mu8.databinding.ActivityCharactersBinding
+import com.architect.coders.mu8.utils.EventObserver
 import com.architect.coders.mu8.utils.getViewModel
 import com.architect.coders.mu8.utils.startActivity
 import com.architect.codes.mu8.characters.CharactersUseCaseImpl
 
 class CharactersActivity : AppCompatActivity() {
 
- private val toolbar: Toolbar by lazy { findViewById<Toolbar>(R.id.toolbar) }
- private val progress: ProgressBar by lazy { findViewById<ProgressBar>(R.id.progress) }
- private val recycler: RecyclerView by lazy { findViewById<RecyclerView>(R.id.recycler) }
-
  private lateinit var viewModel: CharactersViewModel
  private lateinit var adapter: CharactersAdapter
+ private lateinit var binding: ActivityCharactersBinding
 
  override fun onCreate(savedInstanceState: Bundle?) {
  super.onCreate(savedInstanceState)
- setContentView(R.layout.activity_characters)
-
- setSupportActionBar(toolbar)
- supportActionBar?.setDisplayShowTitleEnabled(false)
 
- val toolbarTitle = findViewById<TextView>(R.id.toolbar_title)
- toolbarTitle.text = getString(R.string.characters_name)
+ binding = DataBindingUtil.setContentView(this, R.layout.activity_characters)
 
- viewModel = getViewModel { CharactersViewModel(CharactersUseCaseImpl(CharactersRepositoryImpl(application as DataApp))) }
+ initViewModel()
+ initToolbar()
+ initRecycler()
 
- adapter = CharactersAdapter(viewModel::onCharacterClicked)
- recycler.layoutManager = LinearLayoutManager(this)
- recycler.adapter = adapter
+ viewModel.navigateToCharacter.observe(this, EventObserver { startActivity<CharactersDetailActivity> {} })
+ }
 
- viewModel.model.observe(this, Observer(::updateUi))
+ private fun initViewModel() {
+ viewModel = getViewModel { CharactersViewModel(CharactersUseCaseImpl(CharactersRepositoryImpl(application as DataApp))) }
+ binding.viewmodel = viewModel
+ binding.lifecycleOwner = this
  }
 
- private fun updateUi(model: CharactersUiModel) {
- progress.visibility = if (model == Loading) VISIBLE else GONE
+ private fun initToolbar() {
+ viewModel.setTitle(getString(R.string.characters_name))
+ }
 
- when (model) {
- is Content -> {
- adapter.characters = model.characters
- progress.visibility = GONE
- }
- is Navigation -> startActivity<CharactersDetailActivity> {}
+ private fun initRecycler() {
+ adapter = CharactersAdapter(viewModel::onCharacterClicked)
+ binding.recycler.layoutManager = LinearLayoutManager(this)
+ binding.recycler.adapter = adapter
+
+ with(viewModel.characters) {
+ observe(this@CharactersActivity, Observer {
+ value?.let {
+ adapter.characters = it
+ }
+ })
  }
  }
-}
+}

presentation/src/main/java/com/architect/coders/mu8/characters/CharactersAdapter.kt

@@ -1,45 +1,37 @@
 package com.architect.coders.mu8.characters
 
-import android.view.View
 import android.view.ViewGroup
-import android.widget.ImageView
-import android.widget.TextView
 import androidx.recyclerview.widget.RecyclerView
 import com.architect.coders.mu8.R
-import com.architect.coders.mu8.utils.inflate
+import com.architect.coders.mu8.databinding.ViewCharacterBinding
+import com.architect.coders.mu8.utils.bindingInflate
 import com.architect.coders.mu8.utils.loadUrl
 import com.architect.codes.mu8.characters.Character
 import kotlin.properties.Delegates
 
-class CharactersAdapter(
- private val listener: (Character) -> Unit
-) : RecyclerView.Adapter<CharactersAdapter.ViewHolder>() {
+class CharactersAdapter(private val listener: (Character) -> Unit) : RecyclerView.Adapter<CharactersAdapter.ViewHolder>() {
 
  var characters: List<Character> by Delegates.observable(
  emptyList(),
  { _, _, _ -> notifyDataSetChanged() }
  )
 
- override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
- return ViewHolder(parent.inflate(R.layout.view_character, false))
- }
+ override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder =
+ ViewHolder(parent.bindingInflate(R.layout.view_character, false))
 
  override fun getItemCount(): Int = characters.size
 
  override fun onBindViewHolder(holder: ViewHolder, position: Int) {
  val character = characters[position]
+ holder.dataBinding.character = character
  holder.bind(character)
  holder.itemView.setOnClickListener { listener(character) }
  }
 
- class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
-
- private var characterPicture: ImageView = itemView.findViewById(R.id.image_character_picture)
- private var characterName: TextView = itemView.findViewById(R.id.text_character_name)
+ class ViewHolder(val dataBinding: ViewCharacterBinding) : RecyclerView.ViewHolder(dataBinding.root) {
 
  fun bind(character: Character) {
- characterPicture.loadUrl(character.thumbnailUrl)
- characterName.text = character.name
+ dataBinding.imageCharacterPicture.loadUrl(character.thumbnailUrl)
  }
  }
 }

presentation/src/main/java/com/architect/coders/mu8/characters/CharactersViewModel.kt

@@ -2,26 +2,43 @@ package com.architect.coders.mu8.characters
 
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
+import com.architect.coders.mu8.utils.Event
 import com.architect.coders.mu8.utils.ScopedViewModel
 import com.architect.codes.mu8.characters.Character
 import com.architect.codes.mu8.characters.CharactersUseCase
 import kotlinx.coroutines.launch
 
 class CharactersViewModel(private val charactersUseCase: CharactersUseCase) : ScopedViewModel() {
 
- private val _model = MutableLiveData<CharactersUiModel>()
- val model: LiveData<CharactersUiModel>
- get() {
- if (_model.value == null) getCharacters()
- return _model
- }
+ private val _navigateToCharacter = MutableLiveData<Event<Long>>()
+ val navigateToCharacter: LiveData<Event<Long>> get() = _navigateToCharacter
+
+ private val _loading = MutableLiveData<Boolean>()
+ val loading: LiveData<Boolean> get() = _loading
+
+ private val _characters = MutableLiveData<List<Character>>()
+ val characters: LiveData<List<Character>> get() = _characters
+
+ private val _title = MutableLiveData<String>()
+ val title: LiveData<String> get() = _title
+
+ init {
+ getCharacters()
+ }
 
  private fun getCharacters() {
  launch {
- _model.value = CharactersUiModel.Loading
- _model.value = CharactersUiModel.Content(charactersUseCase())
+ _loading.value = true
+ _characters.value = charactersUseCase()
+ _loading.value = false
  }
  }
 
- fun onCharacterClicked(character: Character) = Unit
+ fun onCharacterClicked(character: Character) {
+ _navigateToCharacter.value = Event(character.id)
+ }
+
+ fun setTitle(toolbarTitle: String) {
+ _title.value = toolbarTitle
+ }
 }

presentation/src/main/java/com/architect/coders/mu8/utils/BindingAdapters.kt

@@ -0,0 +1,11 @@
+package com.architect.coders.mu8.utils
+
+import android.view.View
+import androidx.databinding.BindingAdapter
+
+@BindingAdapter("visible")
+fun View.setVisible(visible: Boolean?) {
+ visibility = visible?.let {
+ if (visible) View.VISIBLE else View.GONE
+ } ?: View.GONE
+}

presentation/src/main/java/com/architect/coders/mu8/utils/Event.kt

@@ -0,0 +1,44 @@
+package com.architect.coders.mu8.utils
+
+import androidx.lifecycle.Observer
+
+/**
+ * Used as a wrapper for data that is exposed via a LiveData that represents an event.
+ * Taken from: https://medium.com/androiddevelopers/livedata-with-snackbar-navigation-and-other-events-the-singleliveevent-case-ac2622673150
+ */
+open class Event<out T>(private val content: T) {
+
+ var hasBeenHandled = false
+ private set // Allow external read but not write
+
+ /**
+ * Returns the content and prevents its use again.
+ */
+ fun getContentIfNotHandled(): T? {
+ return if (hasBeenHandled) {
+ null
+ } else {
+ hasBeenHandled = true
+ content
+ }
+ }
+
+ /**
+ * Returns the content, even if it's already been handled.
+ */
+ fun peekContent(): T = content
+}
+
+/**
+ * An [Observer] for [Event]s, simplifying the pattern of checking if the [Event]'s content has
+ * already been handled.
+ *
+ * [onEventUnhandledContent] is *only* called if the [Event]'s contents has not been handled.
+ */
+class EventObserver<T>(private val onEventUnhandledContent: (T) -> Unit) : Observer<Event<T>> {
+ override fun onChanged(event: Event<T>?) {
+ event?.getContentIfNotHandled()?.let { value ->
+ onEventUnhandledContent(value)
+ }
+ }
+}

presentation/src/main/java/com/architect/coders/mu8/utils/PresentationExtensions.kt

@@ -8,6 +8,8 @@ import android.view.View
 import android.view.ViewGroup
 import android.widget.ImageView
 import androidx.annotation.LayoutRes
+import androidx.databinding.DataBindingUtil
+import androidx.databinding.ViewDataBinding
 import androidx.fragment.app.FragmentActivity
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
@@ -57,3 +59,6 @@ inline fun <reified T : ViewModel> FragmentActivity.getViewModel(crossinline fac
  }
  return ViewModelProviders.of(this, vmFactory)[T::class.java]
 }
+
+fun <T : ViewDataBinding> ViewGroup.bindingInflate(@LayoutRes layoutRes: Int, attachToRoot: Boolean = true): T =
+ DataBindingUtil.inflate(LayoutInflater.from(context), layoutRes, this, attachToRoot)