Navigation Error: action/destination cannot be found from the current destination

user_7358866 0
Viewed 1048

I am using Navigation component to navigate between two Fragments. The landing fragment has a recycler view and the detail fragment has a view pager. I am using a call back listener to trigger navigation action from the recycler view adapter.

The action to be trigger is a zoom event, with the library ZoomHelper ZoomHelper

When the event happens the app crashes with the error above.

However it works well with onclick event listener.

View Holder

class CampaignListViewHolder<T : ViewBinding>(private val binding: T) : RecyclerView.ViewHolder(binding.root) {

    var campaignDetails: CampaignDetails? = null

    @SuppressLint("ClickableViewAccessibility")
    fun bindTo(campaignDetails: CampaignDetails?, position: Int, listener: ItemZoomListener) {
        this.campaignDetails = campaignDetails

        binding as CampaignItemLayoutBinding
        binding.campaignNameTv.text = campaignDetails?.name
        binding.campaignImageIv.load(campaignDetails?.image?.url) {
            crossfade(true)
            placeholder(R.drawable.westwing_placeholder)
        }
        ViewCompat.setTransitionName(binding.campaignImageIv, campaignDetails?.name)
        binding.root.setOnClickListener {
            if (campaignDetails != null) {
                listener.navigate(position)
            }
        }

        ZoomHelper.addZoomableView(binding.campaignImageIv)
        
        ZoomHelper.getInstance().addOnZoomScaleChangedListener(object :
                ZoomHelper.OnZoomScaleChangedListener {
                override fun onZoomScaleChanged(
                    zoomHelper: ZoomHelper,
                    zoomableView: View,
                    scale: Float,
                    event: MotionEvent?
                ) {
                    // called when zoom scale changed
                  
                    if (campaignDetails != null && scale > 1.4) {
                        listener.navigate(position)
                    }
                }
            })
    }
}

Landing Fragment

class LandingFragment : Fragment(R.layout.fragment_landing), ItemZoomListener, FragmentUiStateListener {
    private val TAG by lazy { getName() }
    private val binding by viewBinding(FragmentLandingBinding::bind)
    private val campaignListViewModel: CampaignListViewModel by activityViewModels()
    lateinit var campaignViewAdapter: CampaignListViewAdapter
    lateinit var activityUiState: ActivityUiStateListener
    lateinit var fragmentUiUpdate: FragmentUiStateListener

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        campaignViewAdapter = CampaignListViewAdapter(this)
        fragmentUiUpdate = this
    }

    override fun onResume() {
        super.onResume()
        setupView()
        setUpData()
    }

    private fun setUpData() {
        setUpUiState(campaignListViewModel.campaignUiState, fragmentUiUpdate)
    }

    private fun setupView() {
        val orientation = checkOrientation()
        if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
            binding.campaignLandscapeRcv?.apply {
                layoutManager = GridLayoutManager(requireContext(), 2)
                adapter = campaignViewAdapter
                addItemDecoration(ItemSpaceDecoration(8, 2))
            }
        } else {
            binding.campaignListRcv?.apply {
                layoutManager = LinearLayoutManager(requireContext())
                adapter = campaignViewAdapter
                addItemDecoration(ItemSpaceDecoration(8, 1))
            }
        }
    }

    override fun navigate(position: Int) {
        val direction = LandingFragmentDirections.actionLandingFragmentToCampaignDetailsFragment(position)
        goto(direction)
    }

I understand that one of the reason for the error is probably the zoom event calling the navigation controller multiple times but I can not figure how debug that and what could be a way around this.

android-fragments kotlin android
3 Answers

As you guessed, the issue is most likely caused by the navController being fired multiple times. You can handle this by "navigating safely". Here's a sample implementation below:

fun NavController.safelyNavigate(@IdRes resId: Int, args: Bundle? = null) = 
    try { navigate(resId, args) }
    catch (e: Exception) { Timber.e(e) }
}

You can then make your navigation call like this:

findNavController().safelyNavigate(your_id)

This way, any extra call to NavController.navigate() gets absorbed in the try and catch.

Crash prevented :D

user_56707520

If someone had the same issues due to multiple clicks on the screen. It can be resolved by checking the current destination first before navigating

For example

Fragments A, B, and C

navigating from A to B while clicking on a button in fragment A that navigates to C might lead to crashes in some cases

for that you should check the current destination first as follows:

if(findNavController().currentDestination?.id==R.id.AFragment)
   findNavController().navigate(
   AFragmentDirections.actionAFragmentToCFragment()
 )
user_160590910

If it is being called twice, then you can remove the 'ZoomHelper.OnZoomScaleChangedListener' before the navigation occurs.

I haven't tested the code below, but you can explore the library's code here https://github.com/Aghajari/ZoomHelper/blob/master/ZoomHelper/src/main/java/com/aghajari/zoomhelper/ZoomHelper.kt. You will find a method called 'removeOnZoomScaleChangedListener' which from what I understand, will remove a listener of type 'ZoomHelper.OnZoomScaleChangedListener'.

Ex.

val onZoomScaleChangedListener = object :
                            ZoomHelper.OnZoomScaleChangedListener {
                            override fun onZoomScaleChanged(
                                zoomHelper: ZoomHelper,
                                zoomableView: View,
                                scale: Float,
                                event: MotionEvent?
                            ) {
                                // called when zoom scale changed
                                if (campaignDetails != null && scale > 1.4) {
              ZoomHelper.getInstance().removeOnZoomScaleChangedListener(onZoomScaleChangedListener) // Remove this event listener to avoid multiple triggers as you only need 1.
                                    listener.navigate(position)
                                }
                            }
                        }
        
      ZoomHelper.getInstance().addOnZoomScaleChangedListener(onZoomScaleChangedListener) // You can add the listener above like this.
user_116295340
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