我正在尝试制作一个使用Navigation Drawer Activity的应用程序，但是我需要使用Fragments当我添加Fragments并尝试在其崩溃的片段之间进行切换时，我不解释为什么它使事务崩溃而引发错误：
Process: com.a3.aakap.ftrial, PID: 6958
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.a3.aakap.ftrial/com.a3.aakap.ftrial.MainActivity}: java.lang.RuntimeException: com.a3.aakap.ftrial.MainActivity@9483ac4 must implement OnFragmentInteractionListener
我无法修复它，因为这是我的新手。这是我的MainAcivity.kt文件：
class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
setSupportActionBar(toolbar)
fab.setOnClickListener { view ->
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG).setAction("Action", null).show()
}
val toggle = ActionBarDrawerToggle(this, drawer_layout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close)
drawer_layout.addDrawerListener(toggle)
toggle.syncState()
nav_view.setNavigationItemSelectedListener(this)
title = "Fragment One"
val fragment = FirstFragment()
val fragmentTransaction = supportFragmentManager.beginTransaction()
fragmentTransaction.replace(R.id.first_activity, fragment, "FragmentOne") //create first framelayout with id fram in the …我试图创建一个Spinner内部，Fragment但是在ArrayAdapter构造函数调用中出现错误。我不知道为什么，但是有红色下划线。除此之外，没有错误。当我在中使用相同功能ArrayAdapter时Activity，但在中使用时Fragment，则出现错误。
我的FirstFragment.kt：
class FirstFragment : Fragment() {
private var mListener: OnFragmentInteractionListener? = null
override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
// Inflate the layout for this fragment
return inflater!!.inflate(R.layout.fragment_first, container, false)
}
override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
/*Find the id of spinner*/
val spinner = lol
/*set an adapter with strings array*/
spinner.adapter = ArrayAdapter(this, R.layout.support_simple_spinner_dropdown_item, resources.getStringArray(R.array.atoms)) as SpinnerAdapter? …大家好,我的片段中,我已经在我的片段中添加了一个微调器和一些代码来计算痣但是当我旋转屏幕时它崩溃并抛出一个错误我不知道为什么它会崩溃,当我尝试检查非null对象我不知道那是错误的原因,这是错误:
java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull
这是我的第一个片段文件:
private var mListener: OnFragmentInteractionListener? = null
override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
// Inflate the layout for this fragment
return inflater!!.inflate(R.layout.fragment_first, container, false)
}
override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
//activity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT)
/*Find the id of spinner*/
val spinner = lol
/*set an adapter with strings array*/
spinner.adapter = ArrayAdapter(activity, R.layout.support_simple_spinner_dropdown_item, resources.getStringArray(R.array.atoms)) as SpinnerAdapter
/*set click listener*/
spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener { …大家好，我做了一个抽屉活动，但在我的片段中我想要一个按钮，这样当我按下按钮时，这应该将文本更改为 Hi 或 Hello，但当我尝试在 FirstFragemt 中添加代码时，我不知道代码应该出现在哪里。 kt 文件抛出错误，请帮助我，谢谢
这是我的主要活动：
class MainActivity : AppCompatActivity(),FirstFragment.OnFragmentInteractionListener,SecondFragment.OnFragmentInteractionListener, NavigationView.OnNavigationItemSelectedListener {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
setSupportActionBar(toolbar)
fab.setOnClickListener { view ->
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG).setAction("Action", null).show()
}
val toggle = ActionBarDrawerToggle(this, drawer_layout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close)
drawer_layout.addDrawerListener(toggle)
toggle.syncState()
nav_view.setNavigationItemSelectedListener(this)
}
override fun onBackPressed() {
if (drawer_layout.isDrawerOpen(GravityCompat.START)) {
drawer_layout.closeDrawer(GravityCompat.START)
} else {
super.onBackPressed()
}
}
override fun onCreateOptionsMenu(menu: Menu): Boolean {
// Inflate the menu; this adds items to the action bar if …