那些遇到过的问题

切换片段时应用程序崩溃，selectedItemView 出现错误

Ken*_*ade 0 android kotlin

错误 ：

总共有三个片段。从第三个片段转到第一个片段后发生错误。当从第二个片段转到第一个片段时，我的应用程序不会崩溃。

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.direct.indianpeople, PID: 20204
    java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull, parameter selectedItemView
        at com.example.senthil.kotlin_tablayout.Fragment.nameFrag$onViewCreated$1.onItemSelected(Unknown Source:2)
        at android.widget.AdapterView.fireOnSelected(AdapterView.java:944)
        at android.widget.AdapterView.dispatchOnItemSelected(AdapterView.java:933)
        at android.widget.AdapterView.selectionChanged(AdapterView.java:922)
        at android.widget.AdapterView.checkSelectionChanged(AdapterView.java:1105)
        at android.widget.AdapterView.handleDataChanged(AdapterView.java:1081)
        at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:191)
        at android.widget.Spinner.onMeasure(Spinner.java:602)
        at androidx.appcompat.widget.AppCompatSpinner.onMeasure(AppCompatSpinner.java:428)
        at android.view.View.measure(View.java:23355)
        at androidx.constraintlayout.widget.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
        at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
        at android.view.View.measure(View.java:23355)
        at android.widget.ScrollView.measureChildWithMargins(ScrollView.java:1326)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.widget.ScrollView.onMeasure(ScrollView.java:355)
        at android.view.View.measure(View.java:23355)
        at androidx.viewpager.widget.ViewPager.onMeasure(ViewPager.java:1638)
        at android.view.View.measure(View.java:23355)
        at androidx.constraintlayout.widget.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
        at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
        at android.view.View.measure(View.java:23355)
        at androidx.constraintlayout.widget.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
        at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6758)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:143)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6758)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1535)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:825)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:704)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6758)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6758)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1535)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:825)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:704)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6758)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at com.android.internal.policy.DecorView.onMeasure(DecorView.java:717)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2919)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1749)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2042)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1637)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7797)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1172)
        at android.view.Choreographer.doCallbacks(Choreographer.java:984)
        at android.view.Choreographer.doFrame(Choreographer.java:809)
E/AndroidRuntime:     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1158)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6898)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:537)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.direct.indianpeople, PID: 20204
    java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull, parameter selectedItemView
        at com.example.senthil.kotlin_tablayout.Fragment.nameFrag$onViewCreated$1.onItemSelected(Unknown Source:2)
        at android.widget.AdapterView.fireOnSelected(AdapterView.java:944)
        at android.widget.AdapterView.dispatchOnItemSelected(AdapterView.java:933)
        at android.widget.AdapterView.selectionChanged(AdapterView.java:922)
        at android.widget.AdapterView.checkSelectionChanged(AdapterView.java:1105)
        at android.widget.AdapterView.handleDataChanged(AdapterView.java:1081)
        at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:191)
        at android.widget.Spinner.onMeasure(Spinner.java:602)
        at androidx.appcompat.widget.AppCompatSpinner.onMeasure(AppCompatSpinner.java:428)
        at android.view.View.measure(View.java:23355)
        at androidx.constraintlayout.widget.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
        at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
        at android.view.View.measure(View.java:23355)
        at android.widget.ScrollView.measureChildWithMargins(ScrollView.java:1326)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.widget.ScrollView.onMeasure(ScrollView.java:355)
        at android.view.View.measure(View.java:23355)
        at androidx.viewpager.widget.ViewPager.onMeasure(ViewPager.java:1638)
        at android.view.View.measure(View.java:23355)
        at androidx.constraintlayout.widget.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
        at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
        at android.view.View.measure(View.java:23355)
        at androidx.constraintlayout.widget.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
        at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6758)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:143)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6758)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1535)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:825)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:704)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6758)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6758)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1535)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:825)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:704)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6758)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at com.android.internal.policy.DecorView.onMeasure(DecorView.java:717)
        at android.view.View.measure(View.java:23355)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2919)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1749)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2042)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1637)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7797)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1172)
        at android.view.Choreographer.doCallbacks(Choreographer.java:984)
        at android.view.Choreographer.doFrame(Choreographer.java:809)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1158)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6898)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:537)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
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代码 ：

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {

        for (state in 0..user.StateName_.size-1){
            state_name.add(user.StateName_[state])
            state_id.add(user.StateId_[state])
        }


        spinnerTemp.adapter = ArrayAdapter(this.context!!, android.R.layout.simple_spinner_dropdown_item,state_name)


        spinnerTemp.setOnItemSelectedListener(object : OnItemSelectedListener {
            override fun onItemSelected(parentView: AdapterView<*>?, selectedItemView: View, position: Int, id: Long){
                    city_name.clear()
                    city_state_id.clear()
                    city_id.clear()
                    for (state in 0..user.CityName_.size - 1) {
                        city_state_id.add(user.CityStateId_[state])
                        if (state_id[position] == city_state_id[state]) {
                            city_name.add(user.CityName_[state])
                            city_id.add(user.CityId_[state])
                        }
                    }
                    spinnerTemp2.adapter = ArrayAdapter(
                        this@nameFrag.context!!,
                        android.R.layout.simple_spinner_dropdown_item,
                        city_name
                    )
            }
            override fun onNothingSelected(parentView: AdapterView<*>?) {
                Toast.makeText(this@nameFrag.context,"${city_id}",Toast.LENGTH_SHORT).show()
            }
        })
        spinnerTemp2.setOnItemSelectedListener(object : OnItemSelectedListener {
            override fun onItemSelected(parentView: AdapterView<*>?, selectedItemView: View, position: Int, id: Long){

            }
            override fun onNothingSelected(parentView: AdapterView<*>?) {

            }
        } )

        get_name.addTextChangedListener(object : TextWatcher {

            override fun afterTextChanged(s: Editable) {}

            override fun beforeTextChanged(s: CharSequence, start: Int,
                                           count: Int, after: Int) {
            }

            override fun onTextChanged(s: CharSequence, start: Int,
                                       before: Int, count: Int) {
                if(check_pass(s.toString()) == true){
                    button14.setOnClickListener {
                        val intent = Intent(this@nameFrag.context, Profile2::class.java)
                        startActivity(intent)
                    }
                }
                else if(check_pass(s.toString()) == false)
                    button14.setOnClickListener{
                        Toast.makeText(activity?.applicationContext,"No User Found", Toast.LENGTH_LONG).show()
                    }

            }
        })
    }
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这是我刚刚编写的一段有趣的代码，而且我对 android 或一般编程都很陌生，所以我不知道出了什么问题。

任何帮助表示赞赏。

我不知道是什么原因造成的。

小智 7

尝试使用“selectedItemView：查看？” 而不是 onItemSelected 回调中参数中的“selectedItemView: View”，看看会发生什么。这些方法期望 selectedItemView 具有可为 null 的类型。

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