Android Kotlin Get Data From A Clicked Item In Recyclerview And Pass It Between Fragments

So I have two data classes (OutletListDataClass and ProductListDataClass) that are currently used by two different fragments (OutletListFragment.kt and ProductListFragment.kt, dire

Solution 1:

If you are using Jetpack Navigation (and as you are referring to things like "navigation graphs", so clearly you are using Jetpack Navigation), then to pass arguments between navigation destinations, you must define an <action with the right arguments that is then passed as some variant of parcelable data to the other fragment.

This is the example from the docs:

<actionandroid:id="@+id/startMyFragment"app:destination="@+id/myFragment"><argumentandroid:name="myArg"app:argType="integer"android:defaultValue="1" /></action>

So in your case, it should like you need something like

<navigation...><actionandroid:id="@+id/toProductListFragment"app:destination="@+id/productListFragment"><argumentandroid:name="stkProdcode"app:argType="string" /></action>

Apparently this stuff only works if you also enable the safeargs plugin (as otherwise you have to "remember" this key yourself, or write the NavDirections class by hand, or put together the Bundle yourself - either way, Jetpack Navigation expects you to use Safeargs to pass arguments):

buildscript {
    dependencies {
        classpath "androidx.navigation:navigation-safe-args-gradle-plugin:2.2.2"

And

apply plugin: "androidx.navigation.safeargs.kotlin"

And then you should be able to do

classOutletListFragment: Fragment(), OutletListOnItemClickListener {
    ....

    overridefunonItemClicked(outlet: OutletListPOJODataClassesDataItem) {
        Navigation.findNavController(view).navigate(NavigationDirections.toProductListFragment(outlet.stkProdcode))
    }
}

And due to limitations of Jetpack Navigation, you also have to duplicate the argument definition into the <fragment tag as well:

<fragmentandroid:id="@+id/productListFragment"android:name="com.example.switchingandroidappproject.mainFragments.ProductListFragment"android:label="ProductListFragment" ><argumentandroid:name="stkProdcode"app:argType="string" /></fragment>

Make sure not to make a typo (android:name mismatch) as you'd run into unexpected failures).

Now you can obtain your arguments on the other side as

valargs= ProductListFragmentArgs.fromBundle(getArguments())
valcode= args.stkProdcode

I don't really use Jetpack Navigation, so I'm surprised to see that you have to duplicate the fragment args to the action args, but there you have it.

---

...to think with what I use in place of Jetpack Navigation, this is as simple as

// send
backstack.goTo(ProductListScreen(stkProdCode))
// receivevalprodCode= getKey<ProductListScreen>().stkProdCode

And is just as (if not more) type-safe. 🙄 *grumble* *grumble* but that doesn't help your case, that's not Jetpack Navigation.