How to transfer data from one Fragment to another?

Question

I am writing an application on Kotlin (Android Studio), using jetpack.navigation architecture. There are two fragments: The first contains a list with class instances, which I display in the RecyclerView, the second for EditText (I fill in the client data). I also use Livedata and ViewModel. The problem is that when I go to the second fragment, fill in the data and confirm, I go to the 1st fragment. As I understand it, the following lines destroy the old Fragment1, and create a new one. the list on the first fragment is reset to zero (although the list is saved when you rotate the screen and minimize the application).

 val client = Clients(id,name,secondName,thirdName, address, creditCard, bankNum)
 val action = Fragment2Directions.actionFragment2ToFragment1(client)
 findNavController().navigate(action)

I could not find how to solve problem using the navigation component. I will be very grateful.

Answer 1

To pass data between two fragments with jetpack navigation you have to use Safe Args

pass an argument section like

 <fragment android:id="@+id/myFragment" >
     <argument
         android:name="myArg"
         app:argType="integer"
         android:defaultValue="0" />
 </fragment>

add classpath "androidx.navigation:navigation-safe-args-gradle-plugin:$nav_version" in top level gradle file

and add the plugin apply plugin: "androidx.navigation.safeargs.kotlin" now send the value like so

override fun onClick(v: View) {
   val amountTv: EditText = view!!.findViewById(R.id.editTextAmount)
   val amount = amountTv.text.toString().toInt()
   val action = SpecifyAmountFragmentDirections.confirmationAction(amount)
   v.findNavController().navigate(action)
}

and receive it as

val args: ConfirmationFragmentArgs by navArgs()

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    val tv: TextView = view.findViewById(R.id.textViewAmount)
    val amount = args.amount
    tv.text = amount.toString()
}

However safeargs works only for primitive types so you have to deconstruct and reconstruct if you're trying to pass Objects