How can I change recyclerview item background color permanent and transact new Fragment? - kotlin

Question

I want to change the color of recyclervView item that I clicked(so user can understand that already checked the detail of the item) and go detail fragment page. However this background color change must be permanent should I store it in livedata of recycler view items. I share my codes at the end I am new to android programming so please explain your solution for beginner and my english level is not good. Thanks for everything.
class AdapterRecycler() :
RecyclerView.Adapter<AdapterRecycler.ViewHolder>()
class ViewHolder(view: View, listener: onItemClickListener) : RecyclerView.ViewHolder(view) {
val name: TextView = view.findViewById(R.id.gameId)
val score: TextView = view.findViewById(R.id.scoreId)
val genre: TextView = view.findViewById(R.id.genres)
val layout1: RelativeLayout = view.findViewById(R.id.rowlayout)
init {
// Define click listener for the ViewHolder's View.
//val textView : TextView = view.findViewById(R.id.gameId)
itemView.setOnClickListener {
layout1.setBackgroundColor(Color.rgb(224,224,224))
listener.onItemClick(adapterPosition)
}
}
}
// Create new views (invoked by the layout manager)
override fun onCreateViewHolder(viewGroup: ViewGroup, viewType: Int): ViewHolder {
// Create a new view, which defines the UI of the list item
val view = LayoutInflater.from(viewGroup.context)
.inflate(R.layout.text_row_item, viewGroup, false)
return ViewHolder(view, listenerItems)
}
class Games : Fragment() {
...
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
...
adapter.setOnItemClickListener(object : AdapterRecycler.onItemClickListener {
override fun onItemClick(position: Int) {
// Fragment transaction to detail page
requireActivity().supportFragmentManager.beginTransaction()
.replace(R.id.fragmentContainerView2, Details()).commit()
}
})
}
Should I store a boolean value in here to save item checked status?
data class Game(val name : String, val score : Int, val genres : Array<String>)
I tried solution at my codes and I get transaction but not the color changes of item layout.

Answer 1

I think it will be good if you'll update your Game model, after it became checked. Something like this:
data class Game(.., var isChecked: Boolean = false)
And inside your AdapterRecycler.onItemClickListener realization call ViewModel function to update isChecked value:
fun onItemChecked(position: Int) {
val item = TODO("get item by position from your live data")
item.isChecked = !item.isChecked
}
In addition, you should override your ViewHolder to setup a background rely on your isCheked value (it will be the same as must be after ViewHolder notify calls):
class ViewHolder(view: View, listener: onItemClickListener) : RecyclerView.ViewHolder(view) {
...
fun bind(item: Game) {
val backColor = if (item.isChecked) Color.GREEN else Color.BLUE
layout1.setBackgroundColor(Color.rgb(224,224,224))
}
}
Call bind function from your AdapterRecycler.onBindViewHolder this way:
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.bind(getItem(position), callback)
}
Don't forget to notify your adapter.

Answer 2

Guys thanks to your replies I reviewed my code and got solution.
Here is my edit at the code:
override fun onBindViewHolder(viewHolder: ViewHolder, position: Int) {
...
val color = if (_data[position].isChecked) Color.rgb(224,224,224) else Color.WHITE
viewHolder.layout1.setBackgroundColor(color)
...
}
That way I change the color of recyclerview item color since I change the fragments make the viewmodel at activity based and used it shared viewModel between fragments
class MainActivity : AppCompatActivity() {
private lateinit var viewModel: GamesViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
...
viewModel = ViewModelProvider(this)[GamesViewModel::class.java]
...
}
Then I added the boolean variable to my model.
data class Game(val name : String, val score : Int, val genres : Array<String>, var isChecked : Boolean = false)
Then I change the liveData's attribute of isChecked at the click listener.
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
adapter.setOnItemClickListener(object : AdapterRecycler.onItemClickListener {
override fun onItemClick(position: Int) {
viewModel= ViewModelProvider(requireActivity()).get(GamesViewModel::class.java)
val item = viewModel.liveData.value!!.get(position)
item.isChecked = true
// toGo next fragment
requireActivity().supportFragmentManager.beginTransaction()
.replace(R.id.fragmentContainerView2, Details()).commit()
}
})
Voilà we got the perfect result thanks for helping me, have a great day.