Android Studio: Set Text in fragment-CodePudding

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!

CodePudding user response：

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

CodePudding user response：

Try this solution.

class HomeFragment : Fragment() {

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

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

        _binding = FragmentHomeBinding.inflate(inflater, container, false)
        return binding.root

    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        binding.exercise.text="This is an exceptionally hardcoded string"

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

        }
    }

    override fun onDestroyView() {
        super.onDestroyView()
        _binding = null
    }
}