So I am currently working on a spinner that changes entries in a list. When loading into the Fragment and loading the List into the spinner adapter and setting up the onItemChangedListener everything works fine. But when the App goes to another Fragment and then goes back the app crashes with the following exception:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: de.heffnersoftware.hsproduction, PID: 13111
java.lang.NullPointerException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkNotNullParameter, parameter view
at de.heffnersoftware.hsproduction.ui.storeManagement.ListFiveFragment$onCreateView$3.onItemSelected(Unknown Source:2)
at android.widget.AdapterView.fireOnSelected(AdapterView.java:957)
at android.widget.AdapterView.dispatchOnItemSelected(AdapterView.java:946)
at android.widget.AdapterView.selectionChanged(AdapterView.java:935)
at android.widget.AdapterView.checkSelectionChanged(AdapterView.java:1118)
at android.widget.AdapterView.handleDataChanged(AdapterView.java:1094)
at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:193)
at android.widget.Spinner.onMeasure(Spinner.java:614)
at androidx.appcompat.widget.AppCompatSpinner.onMeasure(AppCompatSpinner.java:438)
at android.view.View.measure(View.java:24721)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:735)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:481)
at android.view.View.measure(View.java:24721)
at androidx.constraintlayout.widget.ConstraintLayout$Measurer.measure(ConstraintLayout.java:811)
at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.measure(BasicMeasure.java:466)
at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.measureChildren(BasicMeasure.java:134)
at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.solverMeasure(BasicMeasure.java:278)
at androidx.constraintlayout.core.widgets.ConstraintWidgetContainer.measure(ConstraintWidgetContainer.java:120)
at androidx.constraintlayout.widget.ConstraintLayout.resolveSystem(ConstraintLayout.java:1594)
at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1708)
at android.view.View.measure(View.java:24721)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6903)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.view.View.measure(View.java:24721)
at androidx.constraintlayout.widget.ConstraintLayout$Measurer.measure(ConstraintLayout.java:811)
at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.measure(BasicMeasure.java:466)
at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.measureChildren(BasicMeasure.java:134)
at androidx.constraintlayout.core.widgets.analyzer.BasicMeasure.solverMeasure(BasicMeasure.java:278)
at androidx.constraintlayout.core.widgets.ConstraintWidgetContainer.measure(ConstraintWidgetContainer.java:120)
at androidx.constraintlayout.widget.ConstraintLayout.resolveSystem(ConstraintLayout.java:1594)
at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1708)
at android.view.View.measure(View.java:24721)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6903)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:760)
at com.google.android.material.appbar.HeaderScrollingViewBehavior.onMeasureChild(HeaderScrollingViewBehavior.java:99)
at com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:2227)
at androidx.coordinatorlayout.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:831)
at android.view.View.measure(View.java:24721)
at androidx.drawerlayout.widget.DrawerLayout.onMeasure(DrawerLayout.java:1156)
at android.view.View.measure(View.java:24721)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6903)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:145)
at android.view.View.measure(View.java:24721)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6903)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
E/AndroidRuntime: at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
at android.view.View.measure(View.java:24721)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6903)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.view.View.measure(View.java:24721)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6903)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
at android.view.View.measure(View.java:24721)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6903)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at com.android.internal.policy.DecorView.onMeasure(DecorView.java:743)
at android.view.View.measure(View.java:24721)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:3135)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1900)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2200)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1788)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7867)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:967)
at android.view.Choreographer.doCallbacks(Choreographer.java:791)
at android.view.Choreographer.doFrame(Choreographer.java:726)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:952)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7399)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:502)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:980)
Bellow is the Listener and code surrounding it:
val spinner: Spinner = root.findViewById(R.id.store_select_spinner)
val spinnerAdapter: ArrayAdapter<String> = ArrayAdapter(
requireContext(), R.layout.spinner_item, llNames
)
spinnerAdapter.setDropDownViewResource(R.layout.spinner_item)
spinner.adapter = spinnerAdapter
spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
override fun onItemSelected(
parent: AdapterView<*>?,
view: View,
position: Int,
id: Long
) {
}
override fun onNothingSelected(parent: AdapterView<*>?) {
}
}
The error has been solved by the solution Demigod provided.
The code needs to be altered as the following:
spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
override fun onItemSelected(
parent: AdapterView<*>?,
view: View?,
position: Int,
id: Long
) {
StoreListFragment.storeAdapter.changeShelve(llShelveNames[position].first)
}
override fun onNothingSelected(parent: AdapterView<*>?) {
}
}