Tag: navigate

Previously there was no way or guaranteeing that the data handed across in Bundles was what was expected. The safe-args plugin seeks to address this:

dependencies {
  ...
classpath "android.arch.navigation:navigation-safe-args-gradle-plugin:$navigationVersion"

   // NOTE: Do not place your application dependencies here; they belong
   // in the individual module build.gradle files
}

apply plugin: 'com.android.application'

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-kapt'

// Add the safe-args plugin after any others:
apply plugin: 'androidx.navigation.safeargs'

android {
    compileSdkVersion 28
    ...

In the Navigation component select the Fragment which is passing on arguments and add Arguments using the + symbol next to the Arguments section of the GUI. Give each a name and specify type if necessary.

import ...

class TitleFragment : Fragment() {
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                              savedInstanceState: Bundle?): View? {
        val binding: FragmentTitleBinding = DataBindingUtil.inflate(
                inflater, R.layout.fragment_title, container, false)
        binding.playButton.setOnClickListener {v: View ->
 //               v.findNavController().navigate(R.id.action_titleFragment_to_nextFragment) // Before safe-args
          v.findNavController().navigate(TitleFragmentDirections.actionTitleFragmentToNextFragment(firstParameter, secondParameter)) // With safe-args. Creates a class *Directions based on Fragment name with associated actions which take the parameters to be passed on
        }
        setHasOptionsMenu(true)
        return binding.root
    }

    override fun onCreateOptionsMenu(menu: Menu?, inflater: MenuInflater?) {
        super.onCreateOptionsMenu(menu, inflater)
        inflater?.inflate(R.menu.overflow_menu, menu)
    }

    override fun onOptionsItemSelected(item: MenuItem?): Boolean {
        return NavigationUI.onNavDestinationSelected(item!!, view!!.findNavController())
                || super.onOptionsItemSelected(item)
    }
}

In the receiving fragment:

import ...

class NextFragment : Fragment() {
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                              savedInstanceState: Bundle?): View? {
        val binding: FragmentTitleBinding = DataBindingUtil.inflate(
                inflater, R.layout.fragment_next, container, false)
        val args = NextFragmentArgs.fromBundle(arguments!!) // Get arguments.
        Toast.makeText(context, "First Parameter: ${args.firstParameter}, Second Parameter: ${args.secondParameter}", Toast.LENGTH_SHORT).show() // Use the Bundled parameters
        return binding.root
    }
}