How to pass data/object from fragment to activity in kotlin - kotlin

Question

I am tring to pass a list of datas from a fragment to a activity using intent. When sending the data from fragment, the data is exist. But in activity the its says data is null. I am not sure if the way i pass the data is correct or not or is there any better way to pass the data from fragment to activity?
In Fragment
private var selectedBankCard: Channels = Channels //get a list of data from BE
override fun onClick(view: View?) {
when (view?.id) {
R.id.bankcard_layout -> {
try {
if (activity != null) {
val intent =
Intent(context, BankCardListActivity::class.java)
if (selectedBankCard != null) {
intent.putExtra("BANKCARDINFORMATION", selectedBankCard) //upon debug, i can see a selectedBankCard is not null
}
startActivityForResult(intent, 10001)
}
} catch (e: Exception) {
}
}
}
}
}
In Activity
class AutoReloadBankCardListActivity : BaseActivity() {
private lateinit var channels: Channels
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.bank_card)
if (intent == null) {
return
}
channels = intent.getSerializableExtra("BANKCARDINFORMATION") as Channels // upon debug, getSerializableExtra returns null
}
class Channels : Serializable {
var newCard = false
var disable = false
var disableCode: String = ""
var description: String = ""
var channelType: String = ""
var payBrands: List<String>? = null
var channelIndex: String = ""
var payToolType: String = ""
var selected = false
var payBrand: String = ""
var extendInfo: ExtendInfo? = null
var disableReason: String = ""
var icon: String = ""
var chargeIndex: String = ""
}

Answer 1

better way to pass the data from fragment to activity?
Better way is listener. You can use interface or lambda in kotlin.
Your fragment. Category is your data/object in this example
class MyFragment : Fragment() {
var listener: ((category: Category) -> Unit)? = null
fun sendCategoryToListener(category: Category) {
listener?.invoke(category)
}
}
Code in your activity
val fragment = MyFragment()
fragment.listener = { category ->
// Do what you want with your object
}

Answer 2

Can you provide the class definition of selectedBankCard?
The type of selectedBankCard must implement the Serializable interface, otherwise the data cannot be obtained in the Activity.
data class Channels(
var newCard = false,
var disable = false,
var disableCode: String = "",
var description: String = "",
var channelType: String = "",
var payBrands: List<String>? = null,
var channelIndex: String = "",
var payToolType: String = "",
var selected = false,
var payBrand: String = "",
var extendInfo: ExtendInfo? = null,
var disableReason: String = "",
var icon: String = "",
var chargeIndex: String = ""
) : Serializable

Answer 3

if you use this code to start a fragment from an activity then you can easily get the return data like this.
Code to start fragment
fun addFragment(
fragment: Fragment,
) {
supportFragmentManager.beginTransaction()
.add(R.id.nav_host_fragment, fragment)
.addToBackStack(BACK_STACK)
.commit()
}
addFragment(ABCFragment(item->{//here the item is your return data}))
You can add fragment like this
and to get return data you can add fragment like this
addFragment(ABCFragment( private val returnData: (item: ABCModel) -> Unit,))
and in fragment write this code
class ABCFRagment(private val returnData: (item: ABCModel) -> Unit,):Fragment{
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
item.invoke(data)
}}
and in activity you can get your return data as item