Spinner在Kotlin上没有工作

Question

旋转器只是不起作用，我尝试了代码的不同版本，但是它在其中任何一个

人都无法帮助解决这个问题吗？

transferfragment.kt

    package com.example.hotel2.transfer
    
    class TransferFragment : Fragment(){
    
        private var _binding: FragmentTransferBinding? = null
        private val binding get() = _binding!!
    
        override fun onCreateView(
            inflater: LayoutInflater, container: ViewGroup?,
            savedInstanceState: Bundle?
        ): View? {
            // Inflate the layout for this fragment
            _binding = FragmentTransferBinding.inflate(inflater, container, false)
            val view = binding.root
            return view
    
            val transfers = arrayOf<String>("Flowers", "Candies")
            val adapter: ArrayAdapter<String> =
                ArrayAdapter<String>(activity?.applicationContext!!, android.R.layout.simple_spinner_item, transfers)
            adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
            val spinner = binding.spinner
            spinner.adapter = adapter
            spinner.prompt = "Title"
            spinner.setOnItemSelectedListener(object : AdapterView.OnItemSelectedListener {
                override fun onItemSelected(
                    parent: AdapterView<*>?, view: View?,
                    position: Int, id: Long
                ) {
    
                }
    
                override fun onNothingSelected(arg0: AdapterView<*>?) {}
            })
    
        }
    
        override fun onDestroyView() {
            super.onDestroyView()
            _binding = null
        }
    }

fragment_transfer.xml

    <?xml version="1.0" encoding="utf-8"?>
    <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".transfer.TransferFragment">
    
        <Spinner
            android:id="@+id/spinner"
            android:layout_width="200dp"
            android:layout_height="wrap_content"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:layout_marginTop="300dp"
            android:layout_marginStart="50dp"></Spinner>
    
    </androidx.constraintlayout.widget.ConstraintLayout>

根据我的猜测，问题是在活动中？.applicationContext !!，但我不明白如何如何了解如何解决它。

Answer 1

在oncreateview（）中，您将此语句作为方法中的第四语句：

return view

此语句之后的所有代码未被执行。

有趣的是，您的IDE（Android Studio或其他）应该告诉您！