Develop Reference

Horizontal RecyclerView with dynamic item height

I am trying to create a horizontal recycler view with dynamic height by following this stack overflow post. The solution seems working. But the recycler view items disappear when I try to remove an item from recycler view.
recyclerview layout:
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:clipToPadding="false"
android:orientation="horizontal"
android:paddingStart="13dp"
android:paddingEnd="13dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
Recycler view item layout:
<androidx.cardview.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="4dp"
android:layout_marginStart="4dp"
app:cardBackgroundColor="#BCAAAA"
app:cardElevation="2dp">
<TextView
android:padding="36dp"
android:id="#+id/textViewName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:textSize="22sp"
tools:text="Test String"/>
</androidx.cardview.widget.CardView>
Activity:
val flexBoxLayoutManager = FlexboxLayoutManager(this, FlexDirection.ROW, FlexWrap.NOWRAP)
with(recyclerView) {
layoutManager = flexBoxLayoutManager
adapter = RecyclerViewAdapter()
setHasFixedSize(false)
}
Adapter:
class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
var textViewName: TextView = itemView.findViewById(R.id.textViewName)
init {
updateLayoutParamsToAllowHorizontalScrolling()
}
private fun updateLayoutParamsToAllowHorizontalScrolling() {
(itemView.layoutParams as? FlexboxLayoutManager.LayoutParams)?.let {
it.flexShrink = 0.0f
it.alignSelf = AlignItems.FLEX_START
}
}
}
override fun onBindViewHolder(holder: RecyclerViewAdapter.ViewHolder, position: Int) {
val item = listItems[position]
var msg = "Sample item no:$position "
for(i in 0..position){
msg += "dynamic content \n"
}
holder.textViewName.text = msg
holder.itemView.setOnClickListener {
val pos = listItems.indexOf(item)
listItems.removeAt(pos)
notifyItemRemoved(pos)
}
}
A screen recording of the output:
Is there any way to fix this issue? Or Are there any other approach to implement horizontal recyclerveiw with dynamic height?

I have fixed the issue without using FlexBoxLayoutManger.
Used LinearLayoutManager with horizontal orientation and the following code in onBindViewHolder in RecyclerViewAdapter.
holder.itemView.post {
val wMeasureSpec =
View.MeasureSpec.makeMeasureSpec(holder.itemView.width, View.MeasureSpec.EXACTLY)
val hMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED)
holder.itemView.measure(wMeasureSpec, hMeasureSpec)
if (holder.itemView.measuredHeight > holder.itemView.height) {
holder.itemView.layoutParams =
(holder.itemView.layoutParams as ViewGroup.LayoutParams)
.apply {
height = holder.itemView.measuredHeight
}
}
}

Recyclerview view not populating

I'm a Kotlin newbie learning how to create simple recyclerview apps. My code is supposed to list the integers 1..10 in vertically stacked cells. However, it only lists the first item. I've consulted several tutorials and reviewed my code several times(after long breaks), but I can't see anything wrong in my code.
I got the bright idea early today to print Log statements. Examining them, I note that my onBindViewHolder function is only called once. What blunder am I making?
Here is my log output:
D/QuoteAdapter: value is: 1
D/QuoteAdapter: index is: 0
D/QuoteAdapter: Size is: 10
my activity:
class MainActivity : AppCompatActivity() {
lateinit var mRecyclerView: RecyclerView
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
mRecyclerView = findViewById(R.id.recyclerView)
mRecyclerView.layoutManager = LinearLayoutManager(this)
mRecyclerView.adapter = QuoteAdapter()
//mRecyclerView.setHasFixedSize(true)
}
}
my adapter:
class QuoteAdapter : RecyclerView.Adapter<QuoteViewHolder>() {
private val listOfInts = intArrayOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
private val TAG = "QuoteAdapter"
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): QuoteViewHolder {
val view = LayoutInflater.from(parent.context)
.inflate(R.layout.recyclerview_item_row, parent, false)
return QuoteViewHolder(view)
}
override fun getItemCount(): Int {
Log.d(TAG, "Size is: ${listOfInts.size.toString()}")
return listOfInts.size
}
override fun onBindViewHolder(holder: QuoteViewHolder, position: Int) {
val item = listOfInts[position]
Log.d(TAG, "value is: ${item.toString()}")
Log.d(TAG, "index is: ${position.toString()}")
holder.listTitle.text = item.toString()
}
}
my viewholder:
class QuoteViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val listTitle = itemView.findViewById(R.id.itemString) as TextView
}
my layout:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/itemString"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
my main layout is shown below:
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

In your "my layout" try this:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/itemString"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
Notice layout_height of LinearLayout has changed to wrap_content
Also doubt you need the android:orientation="vertical" on your ViewHolders item xml unless you will add more than just 1 TextView in the future.

Like Zain says, you can just use a TextView on its own in a layout file, which will also fix the problem (so long as its height is wrap_content!)
There are actually a few included with Android - type android.R.layout. and you'll see a few things, like simple_list_item_1 which is just a styled TextView (you can ctrl+click the reference or whatever to look at the file). Can be nice if you just want to make a quick thing!
The ID of the TextView in android.R.layout.simple_list_item_1 is #android:id/text1 - note the android prefix, because its part of the android resources, not your app's. Which means you have to reference the ID in the same way as the layout, with android at the front: android.R.id.text1

You can get rid of the LinearLayout in the list item layout, and only keep the TextView.
So, replace your list item layout with:
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/itemString"
android:layout_width="match_parent"
android:layout_height="wrap_content" />

How to change attribute of view programatically from the view in my recyclerView in my fragment?

I set the margin of the view (card view) in my xml of my item file, this xml item file will be used in for my recyclerView adapter.
As you can see in my xml below, that I have given margin to top, bottom, start and end. and I want to change the margin from my fragment
Here is my xml file, item_category_list.xml:
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:cardCornerRadius="8dp"
app:cardElevation="4dp"
android:id="#+id/cardView_item_category_list" android:layout_marginStart="8dp" android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp" android:layout_marginTop="8dp">
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#android:color/background_light">
<ImageView
android:layout_width="0dp"
android:layout_height="0dp"
app:srcCompat="#drawable/logo_apps"
android:id="#+id/categoryImageView_Item"
android:layout_marginTop="16dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginStart="24dp"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginEnd="24dp"
app:layout_constraintDimensionRatio="w,1:1" android:scaleType="centerCrop"/>
<TextView
android:text="#string/Category"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/categoryName_textView_item"
app:layout_constraintTop_toBottomOf="#+id/categoryImageView_Item"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginStart="4dp"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginEnd="4dp"
android:textAlignment="center"
android:minLines="1"
android:maxLines="2"
app:autoSizeTextType="uniform"
app:autoSizeMinTextSize="10sp"
app:autoSizeMaxTextSize="15sp"
app:autoSizeStepGranularity="1sp"
android:layout_marginBottom="24dp"
android:layout_marginTop="24dp"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
Here is the adapter:
class CategoryAdapter(val context: Context, val categories: List<Category>) : RecyclerView.Adapter<CategoryAdapter.ViewHolderCategory>() {
private lateinit var mListener : CategoryAdapterListener
interface CategoryAdapterListener {
fun onItemClick(position: Int)
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolderCategory {
val layoutInflater = LayoutInflater.from(parent.context)
val itemView = layoutInflater.inflate(R.layout.item_category_list,parent, false)
return ViewHolderCategory(itemView,mListener)
}
override fun getItemCount(): Int {
return categories.size
}
override fun onBindViewHolder(holder: ViewHolderCategory, position: Int) {
val category = categories[position]
holder.categoryNameTextView.text = category.name
Glide
.with(context)
.load(category.getFormattedImageURL())
.into(holder.categoryImageView)
}
inner class ViewHolderCategory(itemView: View, listener: CategoryAdapterListener) : RecyclerView.ViewHolder(itemView) {
val categoryImageView = itemView.findViewById<ImageView>(R.id.categoryImageView_Item)
val categoryNameTextView = itemView.findViewById<TextView>(R.id.categoryName_textView_item)
val cardView = itemView.findViewById<CardView>(R.id.cardView_item_category_list)
init {
itemView.setOnClickListener {
val position = adapterPosition
if (position != RecyclerView.NO_POSITION) {
listener.onItemClick(position)
}
}
}
}
fun setCategoryAdapterListener(listener: CategoryAdapterListener) {
mListener = listener
}
}
and in the fragment, I set the adapter to the recycler view:
val categoryAdapter = CategoryAdapter(mContext,parentCategory)
val layoutManager = GridLayoutManager(mContext,4,RecyclerView.VERTICAL,false)
recyclerViewParentCategory.adapter = categoryAdapter
recyclerViewParentCategory.layoutManager = layoutManager
recyclerViewParentCategory.setHasFixedSize(true)
I want to change that margin in card view in my item_category_list.xml programatically in my java/kotlin file (in my fragment file), so I can change the margin from my fragment.
So how can I achieve it ? Java/Kotlin any language is preferred.

First Of all its a long way . So i'm just suggesting a way .
First of all . In your Fragment when some action happen you need to change cardview
size in adapter list item xml.
So . You need a interface for that (Let's say interface ChangeMargin). create
interface in Fragment and implement that interface in your adapter like this
class CategoryAdapter(val context: Context, val categories: List<Category>):RecyclerView.Adapter<CategoryAdapter.ViewHolderCategory>(),ChangeMargin()
For how to create interface so can go through this
Now in that interface you need to get cardview and assign new margin .
#Override
public void ChangeMargin() {
val linear_params=LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT)
linear_params.setMargins(leftMargin,topmargin,rightMargin,bottomMargin)
cardView?.layoutParams=linear_params
}
and don't forget to notify adapter

You can do something like this.
Make id of cardview , create instance of it in your adapter and do this code
ViewGroup.MarginLayoutParams layoutParams =
(ViewGroup.MarginLayoutParams) myCardView.getLayoutParams();
layoutParams.setMargins(10, 10, 10, 10);
myCardView.requestLayout();

To set margins to the cardView, you will have to create layoutParams, set margins to it and then set it as cardView LayoutParams like:
inner class ViewHolderCategory(itemView: View, listener: CategoryAdapterListener) : RecyclerView.ViewHolder(itemView) {
val categoryImageView = itemView.findViewById<ImageView>(R.id.categoryImageView_Item)
val categoryNameTextView = itemView.findViewById<TextView>(R.id.categoryName_textView_item)
val cardView = itemView.findViewById<CardView>(R.id.cardView_item_category_list)
//Main code here
val lparams=LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT)
lparams.setMargins(leftMargin,topmargin,rightMargin,bottomMargin)
cardView?.layoutParams=lparams
}

Recyclerview only showing first value

i am having an issue with my gson parsing. I have a nested gson and i would like get the value of "name" under attributes. The problem is my recyclerview is only showing the first value(which is bill 1) and not bill 2 or bill 3. here is my code
// MainActivity.kt
recycler_view.layoutManager = LinearLayoutManager(requireContext())
recycler_view.addItemDecoration(LineItemDecorator(requireContext()))
val bill = GsonBuilder().create().fromJson(jsonString, Bills::class.java)
val nameList: List<Bill> = Arrays.asList(bill)
val adapter = BillsRecyclerAdapter(nameList)
recycler_view.adapter = adapter
adapter.notifyDataSetChanged()
// Bills.kt
data class Bills(
val data: ArrayList<Data>,
val meta: Meta,
val links: Links
)
// BillsRecyclerAdapter.kt
class BillsRecyclerAdapter(private val items: List<Bill>):
RecyclerView.Adapter<BillsRecyclerAdapter.BillsHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BillsHolder {
return BillsHolder(parent.inflate(R.layout.bills_list_item))
}
override fun onBindViewHolder(holder: BillsHolder, position: Int) {
holder.billName.text = items[position].data[position].attributes.name
}
override fun getItemCount() = items.size
class BillsHolder(view: View): RecyclerView.ViewHolder(view) {
val billName: TextView = view.billName
val billAmount: TextView = view.billAmount
}
}
<!-- recyclerview.xml -->
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recycler_view"
android:layout_marginTop="#dimen/materialize_toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
<!-- bill_list_item.xml-->
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/billName"
android:textSize="20sp"
android:layout_marginStart="8dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"/>
<TextView
android:id="#+id/billAmount"
android:textSize="20sp"
android:layout_marginEnd="8dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintEnd_toEndOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
here is my json string. https://pastebin.com/iEqhmB35
thanks for any help provided

Check the following
Check your items.size if it really is not zero,
Also check your bills_list_item.xml try to set the root parent's height to wrap_content
Also check if you have this on you recyclerview
recyclerView.setHasFixedSize(true);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
What's important there is the layout manager
If it doesn't help, can you share your Bills.java class, there might be something wrong with the serialization of JSON raw data.
Hope this helps.
Cheers

How to show part of next/previous card RecyclerView

What is the best strategy to achieve this feature:
I Have a horizontal RecyclerView with cards.
Each card will fulfil the entire screen, but I want it to show part of the next card and previous one if it has more than one item.
I know I can achieve this by setting my card android:layout_width at the adapter to have a specific DP like 250dp instead of match_parent.
But it doesn't look like a proper solution.
This is my code:
Activity with RecyclerView:
class ListPokemon : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val items = createListPokemons()
recyclerView.adapter = PokemonAdapter(items)
recyclerView.layoutManager = LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false)
recyclerView.setHasFixedSize(true)
val pagerSnapHelper = PagerSnapHelper()
pagerSnapHelper.attachToRecyclerView(recyclerView)
}
private fun createListPokemons(): List<Pokemon> {
val pokemons = ArrayList<Pokemon>()
pokemons += createPokemon("Pikachu")
pokemons += createPokemon("Bulbasaur")
pokemons += createPokemon("Charmander")
pokemons += createPokemon("Squirtle")
return pokemons
}
private fun createPokemon(name: String) = Pokemon(name = name, height = 1, weight = 69, id = 1)
}
Layout of Activity:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<android.support.v7.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layoutManager="android.support.v7.widget.LinearLayoutManager"/>
</android.support.constraint.ConstraintLayout>
Adapter:
class PokemonAdapter(val list: List<Pokemon>) : RecyclerView.Adapter<PokemonAdapter.PokemonVH>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PokemonAdapter.PokemonVH {
return PokemonVH(LayoutInflater.from(parent.context)
.inflate(R.layout.pokemon_item, parent, false))
}
override fun onBindViewHolder(holder: PokemonAdapter.PokemonVH, position: Int) {
holder.textViewName.text = list[position].name
}
override fun getItemCount(): Int {
return list.size
}
class PokemonVH(itemView: View) : RecyclerView.ViewHolder(itemView) {
var textViewName: TextView = itemView.findViewById(R.id.textViewName)
}
}
Layout of Adapter:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
android:layout_gravity="center_horizontal"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginEnd="16dp"
app:cardCornerRadius="8dp"
app:cardElevation="4dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:padding="36dp"
android:id="#+id/textViewName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:textSize="22sp"
tools:text="Teste String"/>
</LinearLayout>
</android.support.v7.widget.CardView>
This is my result:
I would like to show part of the next card at this situation. How can I do this?
Thanks.

What you need to do is set padding to your RecyclerView, set clipToPadding to false, use a SnapHelper with it, and you need to make sure the margins on your cards are less than or equal to the padding in the RecylerView.
So, let's say you want the distance from the cards to the sides of the screen to be 16dp and you want the distance between the cards to be 8dp. You'll have to set the margins on each card to 4dp, so the total margin is 8dp. And you have to set the padding to 12dp, given there's already a margin of 4dp on each side of the card.
It'll look a bit like this:
Your list:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layoutManager="android.support.v7.widget.LinearLayoutManager"
android:clipToPadding="false"
android:orientation="horizontal"
android:paddingStart="12dp"
android:paddingEnd="12dp"/>
Your cards:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="4dp"
android:layout_marginStart="4dp"
app:cardElevation="2dp"/>

I think the padding solution is not a good for all cases, because forces the last item to have padding to the right.
Personally i use runtime width calculation of each item and i am very satisfied with this. So you can do the following:
onBindViewHolder
if (position == data.size - 1) {
holder.itemView.layoutParams = RecyclerView.LayoutParams(RecyclerView.LayoutParams.MATCH_PARENT, RecyclerView.LayoutParams.WRAP_CONTENT)
} else {
if (width == null) {
holder.itemView.viewTreeObserver.addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener {
override fun onGlobalLayout() {
holder.itemView.viewTreeObserver.removeOnGlobalLayoutListener(this)
width = holder.itemView.width
params.width = width!! - partOfPage
holder.itemView.requestLayout()
}
})
} else {
params.width = width!! - partOfPage
holder.itemView.requestLayout()
}
}
The outcome is that all middle items are rendered showing a part of the next page, but the last one is rendered full width.

Change your CardView width from "match_parent" to "0dp". And add, layout_weight as "80" (or similar). Make your parent view (RecyclerView) layout_weightSum as "100".
android:layout_width="0dp"
android:layout_weight="80"