Kotlin rotateAnimation is not working. Nothing is happening when the spinBtn is clicked-CodePudding

***I am trying to create af spinningWheel animation with my imageView spinning once the button is pressed. I found a youtube video with some java code i converted into kotlin. With the code below nothing happens when the button is pushed. I have used the rotateAnimation class and some calculations in the GameViewModel thus far, and call the spin() in the GameFragment class' onCreateView().

The code below are the two classes i use for the rotateAnimation but it doesn't seem to work. I am not sure which part is the problem. Does anyone know?***

class GameViewModel : ViewModel() {

private val fields = arrayOf("1","2","3","4","5","6","7")
private val fieldDegrees = IntArray(fields.size)
private var degree = 0
var isSpinning = false


fun getDegreesForSectors(){
    val oneFieldsDegrees = 360/fields.size
    for (i in fields.indices){
        fieldDegrees[i] = (i 1) * oneFieldsDegrees
    }
}


fun spin(imageView: ImageView){
    isSpinning = true
    degree = (0..fields.size).random()

    val rotateAnimation = RotateAnimation(0.toFloat(),
        (360 * fields.size   fieldDegrees[degree]).toFloat(),
        RotateAnimation.RELATIVE_TO_SELF, 0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f)

    rotateAnimation.setDuration(3600)
    rotateAnimation.setFillAfter(true)
    rotateAnimation.setInterpolator(DecelerateInterpolator())
    rotateAnimation.setAnimationListener(object : Animation.AnimationListener{

        override fun onAnimationStart(animation: Animation) {}

        override fun onAnimationEnd(animation: Animation) {
            isSpinning = false
        }
        override fun onAnimationRepeat(animation: Animation) {}

    })
    imageView.startAnimation(rotateAnimation)
}

}

class GameFragment : Fragment() {

private lateinit var gameViewModel: GameViewModel
private var _binding: GameFragmentBinding? = null

// This property is only valid between onCreateView and
// onDestroyView.
private val binding get() = _binding!!


override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View {

    gameViewModel =
        ViewModelProvider(this).get(GameViewModel::class.java)


    val spinBtn: Button? = view?.findViewById(R.id.spinBtn)
    val wheelImage: ImageView? = view?.findViewById(R.id.Spinning_Wheel)
    gameViewModel.getDegreesForSectors()
    spinBtn?.setOnClickListener() {
        if (!gameViewModel.isSpinning) {
            gameViewModel.spin(wheelImage!!)
        }
    }


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



}

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

}

CodePudding user response：

You are accessing fragment view inside onCreateView(). This will return null since nothing has been inflated yet. Use the binding variable to access the views.

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View {

    gameViewModel = ViewModelProvider(this).get(GameViewModel::class.java)

    _binding = GameFragmentBinding.inflate(inflater, container, false)

    gameViewModel.getDegreesForSectors()
    binding.spinBtn.setOnClickListener() {
        if (!gameViewModel.isSpinning) {
            gameViewModel.spin(binding.spinningWheel)
        }
    }

  return binding.root
}