I am creating one Android app and trying to set the data in Recyclerview, I am using MVVM architecture pattern with kotlin, I can see data in logcat but when app loads I am not seeing any data in my recyclerview. Following is my code.
MainActivity
class MainActivity : AppCompatActivity() {
lateinit var productViewModel: ProductViewModel
private lateinit var binding: ActivityMainBinding
val adapter = ProductAdapter()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding.root)
val productService = RetrofitHelper.getInstance().create(ProductService::class.java)
val productRepository = ProductRepository(productService)
productViewModel = ViewModelProvider(this, ProductViewModelFactory(productRepository)).get(ProductViewModel::class.java)
binding.recyclerview.adapter = adapter
productViewModel.products.observe(this,{
Log.d("TEST",it.toString())
adapter.notifyDataSetChanged()
})
}
}
ProductAdapter
class ProductAdapter : RecyclerView.Adapter<ProductViewHolder>() {
var movies = mutableListOf<MobileList>()
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ProductViewHolder {
val inflater = LayoutInflater.from(parent.context)
val binding = AdapterLayoutBinding.inflate(inflater, parent, false)
return ProductViewHolder(binding)
}
override fun onBindViewHolder(holder: ProductViewHolder, position: Int) {
val movie = movies[position]
holder.binding.name.text = movie.products.get(position).name
Glide.with(holder.itemView.context).load(movie.products.get(position).image_url).into(holder.binding.imageview)
}
override fun getItemCount(): Int {
return movies.size
}
}
class ProductViewHolder(val binding: AdapterLayoutBinding) : RecyclerView.ViewHolder(binding.root) {
}
Repository class
class ProductRepository (private val productService: ProductService) {
private val productLiveData = MutableLiveData<MobileList>()
val products:LiveData<MobileList>
get() = productLiveData
suspend fun getProducts(){
val products = productService.getQuotes()
if(products?.body()!=null)
{
productLiveData.postValue(products.body())
}
}
}
ViewModel
class ProductViewModel (private val productRepository: ProductRepository ) :ViewModel() {
init {
viewModelScope.launch(Dispatchers.IO){
productRepository.getProducts()
}
}
val products : LiveData<MobileList>
get() = productRepository.products
}
Factory
class ProductViewModelFactory (private val productRepository: ProductRepository) : ViewModelProvider.Factory {
override fun <T : ViewModel?> create(modelClass: Class<T>): T {
return ProductViewModel (productRepository) as T
}
}
Model
data class MobileList(
val products: List<Product>
)
data class Product(
val image_url: String,
val name: String,
val price: String,
val rating: Int
)
JSON Response
{
"products": [
{
"name": "test",
"price": "34999",
"image_url": "url",
"rating": 4
},
{
"name": "test2",
"price": "999",
"image_url": "url",
"rating": 4
},]}
First of all make sure you have layoutManager set on the RecyclerView.
The problem here is Your ProductAdapter never had the data . notifyDataSetChanged is not a magic stick to notify the adapter you modify/add/update the dataset and then You will call notifyDataSetChanged . that's how it works .
In your case You have movies list your adapter but you never assigned anything to it its always empty .
There are several ways to it. Just to make it work You can have a method to add the data in your adapter and then notify it.
fun addData(data:List<MobileList>){
movies.addAll(data)
notifyDataSetChanged()
}
Now when you get the data inside on change you call this method .
productViewModel.products.observe(this,{
it?.let{ items ->
adapter.addData(items)
}
})
This should work .
Update on type fix - Seems like your type is messed up . Why is your repo returns a object of MobileList? While you are using a list of MobileList in adapter . Your adapter should hold var movies = mutableListOf<Products>().
productViewModel.products.observe(this,{
it?.let{ item ->
adapter.addData(item.products)
}
})
Related
I am trying to parse JSON (https://raw.githubusercontent.com/Biuni/PokemonGO-Pokedex/master/pokedex.json) to show data in RecyclerView, but I get an error:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myapplication, PID: 13534
java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:350)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:80)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:61)
at retrofit2.converter.gson.GsonResponseBodyConverter.convert(GsonResponseBodyConverter.java:39)
at retrofit2.converter.gson.GsonResponseBodyConverter.convert(GsonResponseBodyConverter.java:27)
at retrofit2.OkHttpCall.parseResponse(OkHttpCall.java:243)
at retrofit2.OkHttpCall$1.onResponse(OkHttpCall.java:153)
at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:519)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:919)
I see that the problem is that JSON contains just 1 object (pokemon) and inside this object there is array of different pokemons. I don't know how to parse array inside the upper level object in JSON. What should I change to make it work?
I suppose that I should save this pokemon object and then parse it but I don't know hot to get inside it.
Thanks.
API interface:
interface SimpleApi {
#GET("pokedex.json")
suspend fun getCustomPosts(): Response<List<Post>>
}
Repository:
class Repository {
suspend fun getCustomPosts(): Response<List<Post>>{
return RetrofitInstance.api.getCustomPosts()
}
}
ViewModel:
class MainViewModel(val repository: Repository) : ViewModel() {
val myCustomPosts = MutableLiveData<Response<List<Post>>>()
fun getCustomPosts() {
viewModelScope.launch {
val response: Response<List<Post>> = repository.getCustomPosts()
myCustomPosts.value = response
}
}
}
MainActivity:
class MainActivity : AppCompatActivity() {
private lateinit var viewModel: MainViewModel
private lateinit var binding: ActivityMainBinding
private lateinit var recyclerView: RecyclerView
private lateinit var adapter: MyAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
val view = binding.root
setContentView(view)
setRecyclerView()
val repository = Repository()
val viewModelFactory = MainViewModelFactory(repository)
viewModel = ViewModelProvider(this, viewModelFactory).get(MainViewModel::class.java)
viewModel.getCustomPosts()
viewModel.myCustomPosts.observe(this, Observer { response ->
if (response.isSuccessful) {
response.body()?.let { adapter.setData(it) }
} else {
Toast.makeText(this, response.code(), Toast.LENGTH_SHORT).show()
}
})
}
private fun setRecyclerView() {
adapter = MyAdapter()
recyclerView = binding.recyclerView
recyclerView.layoutManager = LinearLayoutManager(this)
recyclerView.adapter = adapter
}
}
RecyclerView Adapter:
class MyAdapter() : RecyclerView.Adapter<MyAdapter.MyViewHolder>() {
private var postList = emptyList<Post>()
class MyViewHolder(view: View) : RecyclerView.ViewHolder(view) {
val idView: TextView = view.findViewById(R.id.id_txt)
val nameView: TextView = view.findViewById(R.id.name_txt)
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
return MyViewHolder(
LayoutInflater.from(parent.context).inflate(R.layout.row_layout, parent, false)
)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val currentItem = postList[position]
holder.idView.text = currentItem.id.toString()
holder.nameView.text = currentItem.name
}
override fun getItemCount(): Int = postList.size
fun setData(newList: List<Post>){
postList = newList
notifyDataSetChanged()
}
}
Post:
data class Post(
#SerializedName("id")
val id: Int,
#SerializedName("name")
val name: String
)
Try to use next class in response object:
data class PokedexResponse (
#SerializedName("pokemon")
val pokemons: List<Post>
)
interface SimpleApi {
#GET("pokedex.json")
suspend fun getCustomPosts(): Response<PokedexResponse>
}
My guess is that you missed to parse pokemon object:
{
"pokemon": [{ ... }]
}
I am working on one project where I am not able to get json response in my recyclerview but getting response in Viewmodel.
Following is my code. I tried to use debug pointer but I am not getting any information in logcat or debug tab.
class MainActivity : AppCompatActivity() {
private val TAG = "MainActivity"
private lateinit var binding: ActivityMainBinding
lateinit var viewModel: MainViewModel
private val retrofitService = RetrofitService.getInstance()
val adapter = MainAdapter()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding.root)
viewModel = ViewModelProvider(this, MyViewModelFactory(MainRepository(retrofitService))).get(MainViewModel::class.java)
binding.recyclerview.adapter = adapter
viewModel.movieList.observe(this, Observer {
Log.d(TAG, "onCreate: $it")
adapter.setMovieList(it)
})
viewModel.errorMessage.observe(this, Observer {
})
viewModel.getAllMovies()
}
}
Models
data class MobileProducts(
val products: List<Product>
)
data class Product(
val image_url: String,
val name: String,
val price: String,
val rating: Int
)
Retrofit
interface RetrofitService {
#GET("/nancymadan/assignment/db")
fun getAllMovies() : Call<List<MobileProducts>>
companion object {
var retrofitService: RetrofitService? = null
fun getInstance() : RetrofitService {
if (retrofitService == null) {
val retrofit = Retrofit.Builder()
.baseUrl("https://my-json-server.typicode.com")
.addConverterFactory(GsonConverterFactory.create())
.build()
retrofitService = retrofit.create(RetrofitService::class.java)
}
return retrofitService!!
}
}
}
Viewmodel
class MainViewModel constructor(private val repository: MainRepository) : ViewModel() {
val movieList = MutableLiveData<List<MobileProducts>>()
val errorMessage = MutableLiveData<String>()
fun getAllMovies() {
val response = repository.getAllMovies()
response.enqueue(object : Callback<List<MobileProducts>> {
override fun onResponse(call: Call<List<MobileProducts>>, response: Response<List<MobileProducts>>) {
movieList.postValue(response.body())
}
override fun onFailure(call: Call<List<MobileProducts>>, t: Throwable) {
errorMessage.postValue(t.message)
}
})
}
}
JSON RESPONSE
{
"products": [
{
"name": "test",
"price": "34999",
"image_url": "url",
"rating": 4
},
{
"name": "test2",
"price": "999",
"image_url": "url",
"rating": 4
},
{
"name": "test",
"price": "34999",
"image_url": "url",
"rating": 4
},
{
"name": "test2",
"price": "999",
"image_url": "url",
"rating": 4
}
,]}
What is missing can anyone help me.
May be you forgot set LayoutManager for your recyclerview
place this line before set adapter
binding.recyclerview.layoutManager = LinearLayoutManager(context)
You have not set any LayoutManager for the RecyclerView, and RecyclerView will not work without LayoutManger. so you should
add this to your code :
binding.recyclerview.setLayoutManager(LinearLayoutManager(this))
and it will work if your MainAdapter class and the data have no problems.
First thing you set layout manager for Recyclerview.
binding.recyclerview.setLayoutManager(LinearLayoutManager(this))
If you set in XML then no need by programmatically.
After getting response of Viewmodel livedata when you observe list data.
You have set list in adapter but use notify.
Use this.
adapter.notifyDataSetChange()
Or You can use DiffUtill for notifying data in adapter it's good way.
If all this not work then try this one time:::::::::
class MainActivity : AppCompatActivity() {
private val TAG = "MainActivity"
private lateinit var binding: ActivityMainBinding
lateinit var viewModel: MainViewModel
private val retrofitService = RetrofitService.getInstance()
val adapter = MainAdapter()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding.root)
viewModel = ViewModelProvider(this, MyViewModelFactory(MainRepository(retrofitService))).get(MainViewModel::class.java)
//call api first
viewModel.getAllMovies()
//then observe
viewModel.movieList.observe(this, Observer {
Log.d(TAG, "onCreate: $it")
adapter.setMovieList(it)
//after set data in adapter then set recyclerview adapter
binding.recyclerview.adapter = adapter
})
viewModel.errorMessage.observe(this, Observer {
})
}
}
I just want to say sorry to my English skill
I've studied the Android Studio and Kotlin these days.
but I'd got a problem on RecyclerViewer and Adapter, for Intent method
work flow chart
this image, this is what i want to do
so i coded the three classes
ShoppingAppActivity.kt, MyAdapter.kt, CartActivity.kt
At ShoppingAppActivity, If I click the itemId ( in the Red box texts)
I make it move to other context(CartActivity)
ShoppingAppActivity working
if i clicked the red box then
cartStatus
go to cart Activity
it worked but already I said, I just want to send only send itemID
covert to String (i will use toString())
SO i tried to use Intent method in ShoppingAppActivity.kt
///PROBLEM PART
adapter?.setOnItemClickListener{
val nextIntent = Intent(this, CartActivity::class.java)
//nextIntent.putExtra("itemID", )
startActivity(nextIntent)
}
///PROBLEM PART
like this but the problem is I don't know what am i have to put the parameter in
nextIntent.putExtra("itemID", )
what should i do?
I think, I should fix MyAdaptor.kt or ShopingAppActivity.kt for this problem.
But in my knowledge, this is my limit. :-(
below
Full Codes of ShoppingAppActivity.kt, MyAdapter.kt, CartActivity.kt
ShoppingAppActivity.kt
class ShoppingAppActivity : AppCompatActivity() {
lateinit var binding: ActivityShoppingAppBinding
private var adapter: MyAdapter? = null
private val db : FirebaseFirestore = Firebase.firestore
private val itemsCollectionRef = db.collection("items")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityShoppingAppBinding.inflate(layoutInflater)
setContentView(binding.root)
updateList()
binding.recyclerViewItems.layoutManager = LinearLayoutManager(this)
adapter = MyAdapter(this, emptyList())
binding.recyclerViewItems.adapter = adapter
///PROBLEM PART
adapter?.setOnItemClickListener{
val nextIntent = Intent(this, CartActivity::class.java)
//nextIntent.putExtra("itemID", )
startActivity(nextIntent)
}
///PROBLEM PART
}
private fun updateList() {
itemsCollectionRef.get().addOnSuccessListener {
val items = mutableListOf<Item>()
for (doc in it) {
items.add(Item(doc))
}
adapter?.updateList(items)
}
}
}
MyAdapter.kt
data class Item(val id: String, val name: String, val price: Int, val cart: Boolean) {
constructor(doc: QueryDocumentSnapshot) :
this(doc.id, doc["name"].toString(), doc["price"].toString().toIntOrNull() ?: 0, doc["cart"].toString().toBoolean() ?: false)
constructor(key: String, map: Map<*, *>) :
this(key, map["name"].toString(), map["price"].toString().toIntOrNull() ?: 0, map["cart"].toString().toBoolean() ?: false)
}
class MyViewHolder(val binding: ItemBinding) : RecyclerView.ViewHolder(binding.root)
class MyAdapter(private val context: Context, private var items: List<Item>)
: RecyclerView.Adapter<MyViewHolder>() {
fun interface OnItemClickListener {
fun onItemClick(student_id: String)
}
private var itemClickListener: OnItemClickListener? = null
fun setOnItemClickListener(listener: OnItemClickListener) {
itemClickListener = listener
}
fun updateList(newList: List<Item>) {
items = newList
notifyDataSetChanged()
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
val inflater = LayoutInflater.from(parent.context)
val binding: ItemBinding = ItemBinding.inflate(inflater, parent, false)
return MyViewHolder(binding)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val item = items[position]
val itemID : String
holder.binding.textID.text = item.id
holder.binding.textName.text = item.name
if(item.cart)
{
holder.binding.textCart.text = "in Cart"
}
else
{
holder.binding.textCart.text = ""
}
holder.binding.textID.setOnClickListener {
AlertDialog.Builder(context).setMessage("You clicked ${item.id}.").show()
itemClickListener?.onItemClick(item.id)
}
holder.binding.textName.setOnClickListener {
//AlertDialog.Builder(context).setMessage("You clicked ${student.name}.").show()
itemClickListener?.onItemClick(item.id)
}
//return item.id.toString()
}
override fun getItemCount() = items.size
}
CartActivity.kt
class CartActivity : AppCompatActivity() {
lateinit var binding: ActivityCartBinding
private val db: FirebaseFirestore = Firebase.firestore
private val itemsCollectionRef = db.collection("items")
private var adapter: MyAdapter? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityCartBinding.inflate(layoutInflater)
setContentView(binding.root)
updateList()
//binding.recyclerViewItems.layoutManager = LinearLayoutManager(this)
//adapter = MyAdapter(this, emptyList())
//binding.recyclerViewItems.adapter = adapter
binding.changeCartStatus.setOnClickListener{
//change the button's text if the itemID is corrected
//if(){
// binding.changeCartStatus.text = ""
//}
}
}
private fun updateList() {
itemsCollectionRef.get().addOnSuccessListener {
val items = mutableListOf<Item>()
for (doc in it) {
items.add(Item(doc))
}
adapter?.updateList(items)
}
}
}
You just need to implement listener to your activity
class ShoppingAppActivity : AppCompatActivity() ,MyAdapter.OnItemClickListener {
In oncreate add below line after adapter
adapter?.setOnItemClickListener(this)
Then override its method
override fun onItemClick(id: String){
val nextIntent = Intent(this, CartActivity::class.java)
nextIntent.putExtra("itemID",id )
startActivity(nextIntent)
}
I'm trying it implement following Json string:
{
"msg":[
"football",
"cricket",
"baseball",
"rugby",
"gulf"
],
"status":"success"
}
I have created the data classes as below:
class Sports(
val msg : List<String>,
val status : String
)
And
class Msg (
val football : List<String>,
val cricket : List<String>,
val baseball : List<String>,
val rugby : List<String>,
val gulf : List<String>
)
Now I'm trying to get the objects and view it in a recyclerview list as per the tutorial.
How could I change it below & call it in the adapter?
interface PostApi {
/**
* Get the list of the pots from the API
*/
#GET("/posts")
fun getPosts(): Observable<List<Post>>
}
Edit:
MY adapter class as below:
class PostListAdapter: RecyclerView.Adapter<PostListAdapter.ViewHolder>() {
private lateinit var postList:Sports
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PostListAdapter.ViewHolder {
val binding: ItemPostBinding = DataBindingUtil.inflate(LayoutInflater.from(parent.context), R.layout.item_post, parent, false)
return ViewHolder(binding)
}
override fun onBindViewHolder(holder: PostListAdapter.ViewHolder, position: Int) {
holder.bind(postList)
}
override fun getItemCount(): Int {
//Getting error in .isInitialied 'Unresolved reference'
return if(::postList.isInitialized) postList.message.size else 0
}
fun updatePostList(postList: Sports){
this.postList = postList
notifyDataSetChanged()
}
class ViewHolder(private val binding:
ItemPostBinding):RecyclerView.ViewHolder(binding.root){ //Getting error in root 'Unresolved reference'
private val viewModel = PostViewModel()
fun bind(post: Sports){
viewModel.bind(post) //Getting error saying No value passed for parameter 'position'
binding.viewModel = viewModel
}
}
}
If you get the Json from server then call it like below:
interface SportsApi {
/**
* Get the Sports from the API
*/
#GET("/sports")
fun getSports(): Observable<Sports>
}
Or if you want to to check it in locally then you have to convert this Json
Using Gson:
val sports = Gson().fromJson(json, Sports::java.class)
Using Moshi:
val sports = Moshi.Builder().build().adapter(Sports::java.class).fromJson(json)
I want each row of my RecyclerView to display all the details of one document of the collection.
I've used this exact same adapter code, albeit with a different class to serialize into. And it works well. But in this instance, it's simply not working.
But the code just doesn't get into populating the views.
My database is like:
reviews--Orange--vault--|
|-firstReview
|-secondReview
|-sjdeifhaih5aseoi
...
My query and adapter from the fragment:
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
viewModel = ViewModelProviders.of(this).get(ReviewViewModel::class.java)
val reviewQuery = FirebaseFirestore.getInstance().collection("reviews").document("Orange").collection("vault")
val reviewBurnOptions = FirestoreRecyclerOptions.Builder<Review>()
.setQuery(reviewQuery, object : SnapshotParser<Review> {
override fun parseSnapshot(snapshot: DocumentSnapshot): Review {
return snapshot.toObject(Review::class.java)!!.also {
it.id = snapshot.id
}
}
}).setLifecycleOwner(this)
reviewRecycler.adapter=ReviewBurnAdapter(reviewBurnOptions.build())}
class ReviewBurnAdapter(options: FirestoreRecyclerOptions<Review>) :
FirestoreRecyclerAdapter<Review, ReviewBurnAdapter.ViewHolder>(options) {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {//I never reach this point
val view = LayoutInflater.from(parent.context).inflate(R.layout.row_review, parent, false)
return ViewHolder(view)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int, item: Review) {
holder.apply {
holder.itemView.rowAuthor.text = item.author
}
}
inner class ViewHolder(override val containerView: View) :
RecyclerView.ViewHolder(containerView), LayoutContainer
}
Class to serialize into:
import com.google.firebase.firestore.Exclude
import com.google.firebase.firestore.PropertyName
import java.util.*
class Review(
#get:Exclude var id: String = "DEVIL",
#JvmField #PropertyName(AUTHOR) var author: String = "",
#JvmField #PropertyName(WRITEUP) var writeup: String = "",
//#JvmField #PropertyName(MOMENT) var moment:Date=Date(1997,12,1),
#JvmField #PropertyName(RATING) var rating: Int = 0
) {
companion object {
const val AUTHOR = "author"
const val WRITEUP = "writeup"
const val RATING = "rating"
//const val MOMENT="moment"
}
}
Also, there's no errors, it just never reaches the code that would generate and populate with viewHolders.
Alright, the fix was ultra simple, as #Prashant Jha pointed out, I hadn't specified a layout manager for my RecyclerView -_-
To be crystal clear, I added app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
to my xml, and everything worked.