Codelab Kotlin - GDG Lima IO Extended Lima 2019
Slide : https://docs.google.com/presentation/d/1ASbryoETUm3Hgz4BERL45gzpOAdl_YdwVn0PIRgyV8E/edit?usp=sharing
Sample: https://github.com/emedinaa/kotlin-first/archive/master.zip
-
Android Studio 3.3.2 o superior https://developer.android.com/studio
-
Conocimientos básicos de Android https://developer.android.com/
-
Kotlin documentación oficial https://kotlinlang.org/docs/reference/
En esta sección vamos crear un nuevo proyecto usando Android Studio con Kotlin y revisaremos los conceptos básicos del lenguaje Kotlin. Por ejemplo, tipos de Datos, funciones , null safety
private val hero:String= "Iron Man"
private var message="He privatizado exitosamente la paz mundial!"
private var desc:String?=null
private val gender:Int =1
private var photo:Int =0
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_step1)
//supportActionBar?.setDisplayHomeAsUpEnabled(true)
desc= "También conocido en español como el Hombre de Hierro — es un superhéroe ficticio que aparece en los cómics estadounidenses publicados por Marvel Comics. "
imageView.setOnClickListener {
showMessage()
}
}
private fun showMessage(){
val nMessage= hero.plus(" ").plus(message)
Toast.makeText(this,nMessage,Toast.LENGTH_LONG).show()
}
/*override fun onSupportNavigateUp(): Boolean {
onBackPressed()
return true
}*/En esta sección veremos sobre Collections, List, MutableLists y Adapters.
//private var heroList:MutableList<HeroEntity>?=null
private var heroList:MutableList<HeroEntity> = mutableListOf()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_step3)
supportActionBar?.setDisplayHomeAsUpEnabled(true)
val layoutManager= LinearLayoutManager(this,LinearLayoutManager.HORIZONTAL,false)
recyclerView.layoutManager= layoutManager
//load Data
//loadDataWithList()
loadDataWithMutableList()
//loadDataByGender()
//loadDataByGender(1)
}
private fun loadDataByGender(gender:Int=0){
val filter:MutableList<HeroEntity> = mutableListOf()
heroList.forEach {
if(it.gender==gender){
filter.add(it)
}
}
val adapter= HeroHAdapter(filter.toList())
recyclerView.adapter= adapter
}
private fun loadDataWithMutableList(){
heroList.add(HeroEntity("IronMan",R.drawable.iron_man_box,1))
heroList.add(HeroEntity("Scarlet Witch",R.drawable.scarlet_witch_box,0))
heroList.add(HeroEntity("Doctor Strange",R.drawable.doctor_strange_box,1))
heroList.add(HeroEntity("Hulk",R.drawable.hulk_box,1))
heroList.add(HeroEntity("Gamora",R.drawable.gamora_box,0))
heroList.add(HeroEntity("Black Widow",R.drawable.black_widow_box,0))
//heroList.sortBy { it.name }
val adapter= HeroHAdapter(heroList.toList())
recyclerView.adapter= adapter
}
private fun loadDataWithList(){
val data:List<HeroEntity> = listOf(HeroEntity("IronMan",R.drawable.iron_man_box,1),
HeroEntity("Scarlet Witch",R.drawable.scarlet_witch_box,0),HeroEntity("Doctor Strange",R.drawable.doctor_strange_box,1),
HeroEntity("Hulk",R.drawable.hulk_box,1), HeroEntity("Gamora",R.drawable.gamora_box,0),
HeroEntity("Black Widow",R.drawable.black_widow_box,0))
val adapter= HeroHAdapter(data)
recyclerView.adapter= adapter
}
override fun onSupportNavigateUp(): Boolean {
onBackPressed()
return true
}En esta sección veremos sobre Clases,Objetos,Herencia, Data Class y Extensiones
private var photoSelected=0
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_step4)
textViewPhoto.setOnClickListener {
showDialog()
}
button.setOnClickListener {
createHero()
}
}
private fun createHero(){
val name = editTextName.text.toString().trim()
//val desc = editTextDesc.text.toString().trim()
val photo = photoSelected
val hero= HeroEntity(name,photo,0)
val heroView= HeroView(this)
heroView.setEntity(hero)
linerLayout.addView(heroView)
}
override fun onSelectedItem(position:Int,resource: Int) {
textViewPhoto.text= "seleccionado $position"
photoSelected= resource
}
private fun showDialog(){
val galleryDialog:GalleryDialogFragment= GalleryDialogFragment.newInstance("","")
galleryDialog.show(supportFragmentManager, "CustomDialogFragment");
}En esta sección veremos como conectar nuestra app a la nube usando retrofit, usos de funciones como parámetros.
private lateinit var adapter: HeroAdapter
private lateinit var provider: HeroProvider
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_step6)
provider= HeroProvider()
adapter= HeroAdapter(emptyList())
//recyclerView.layoutManager= LinearLayoutManager(this)
recyclerView.layoutManager= GridLayoutManager(this,2)
/*val decorator= DividerItemDecoration(this,DividerItemDecoration.VERTICAL)
val drawable= ContextCompat.getDrawable(this,R.drawable.divider)
drawable?.let {
decorator.setDrawable(it)
}
recyclerView.addItemDecoration(decorator)*/
recyclerView.addItemDecoration(GridItemDecorator(this,4,2))
recyclerView.adapter= adapter
recyclerView.addOnItemTouchListener(RecyclerTouchListener(this,recyclerView,
object:RecyclerClickListener{
override fun onClick(view: View, position: Int) {
val item= adapter.getItem(position)
showItem(item)
}
override fun onLongClick(view: View, position: Int) {
}
}))
}
private fun showItem(hero:Hero){
showToast("Hero ${hero.name}")
}
private fun renderData(data:List<Hero>){
adapter.update(data)
//recyclerView.adapter= HeroAdapter(data)
}
private fun empty(){}
private fun showError(message:String?){}
private fun onResult():(data:DataResult<List<Hero>>)->Unit{
return {
hideLoadingView()
when(it){
is DataResult.Success ->
if(it.data.isEmpty()){
empty()
}else{
renderData(it.data)
}
is DataResult.Failure -> showError(it.e.message)
}
}
}
override fun onResume() {
super.onResume()
/*provider.retrieveHeroes {
when(it){
is DataResult.Success ->
if(it.data.isEmpty()){
empty()
}else{
renderData(it.data)
}
is DataResult.Failure -> showError(it.e.message)
}
}*/
showLoadingView()
provider.retrieveHeroes(onResult())
}
private fun showLoadingView(){
layoutProgress.visibility=View.VISIBLE
}
private fun hideLoadingView(){
layoutProgress.visibility=View.GONE
}
Página oficial https://kotlinlang.org/
Documentación https://kotlinlang.org/docs/reference/
Compilador online https://play.kotlinlang.org/
Android Codelabs https://codelabs.developers.google.com/?cat=Android
Github repositories https://github.com/search?q=language:Kotlin
Training :
- Kotlin for Android Developers https://es.coursera.org/learn/kotlin-for-java-developers
- Kotlin for Android Developers https://www.udacity.com/course/kotlin-for-android-developers
- Kotlin Bootcamp for Programmers https://www.udacity.com/course/kotlin-bootcamp-for-programmers
- Developing Android App with Kotlin https://www.udacity.com/course/developing-android-apps-with-kotlin
Communities :
- Kotlin Perú
- Kotlin for Android Developers [antonioleiva.com]