Android Studio: Set Text in fragment

Question

I've recently picked up an Android Studio project I started a year ago in Kotlin. It features three fragments that can be navigated through by a bottom navigation bar.

Now, to break my current issue down to a simple example that even doesn't work for me: Given there's a the editText object exercise in fragment_home.xml and I want to call and alter it in HomeFragment.kt. I checked every source of advice I could find from Google & Stackoverflow and came up with the following code in HomeFragment.kt (partially pre-coded by AndroidStudio):

    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val homeViewModel =
            ViewModelProvider(this).get(HomeViewModel::class.java)

        _binding = FragmentHomeBinding.inflate(inflater, container, false)
        val root: View = binding.root

        val view: View = inflater!!.inflate(R.layout.fragment_home,container,false)

        view.exercise.setText("This is an exceptionally hardcoded string")

The last line stands for every object I tried to reach. I also tried onClickListening for buttons like so:

val btnNewExercise =  view.findViewById<Button>(R.id.btn_new_exercise)
btnNewExercise.setOnClickListener {view

            Toast.makeText(view.context, "New exercise will be generated", Toast.LENGTH_SHORT).show()
            println("Generated a new exercise")
        }

but nothing happens when I start the app/ hit the buttons - I seem to can't get through to the actual view's objects to access them. Even ran into NullPointerExceptions on my way to a solution.

I could supply the fragment and layout files if needed - just thought this way it might be easier at first.

If anybody could tell me where I'm wrong I'd be really grateful! Thanks in advance!

Answer 1

You inflated the layout twice.

Remove this. You already inflated the layout using view binding in the FragmentHomeBinding.inflate... call

val view: View = inflater!!.inflate(R.layout.fragment_home,container,false)

and replace

view.exercise.setText("This is an exceptionally hardcoded string")

with (using binding

 binding.exercise.setText("This is an exceptionally hardcoded string")

then the last line on your onCreateView should be

   return binding.root

Note: You should have these class properties:

private var _binding: FragmentHomeBinding? = null
private val binding get() = _binding!!

So it will look like this:

               //move your view model as a class property so it will be accessible by other class methods
                 private val homeViewModel =
                          ViewModelProvider(this).get(HomeViewModel::class.java)

 
                 private var _binding: FragmentHomeBinding? = null
                 private val binding get() = _binding!!//transform to immutable
            
                 override fun onCreateView(
                        inflater: LayoutInflater,
                        container: ViewGroup?,
                        savedInstanceState: Bundle?
                    ): View? {

                        
                
                        _binding = FragmentHomeBinding.inflate(inflater, container, false)
                      
                       //use the immutable view binding property
                        binding.exercise.setText("This is an exceptionally hardcoded string")
            
                        return binding.root
                   }

For more info, read view binding