DialogFragment not appearing

2019-08-16 16:44发布

问题:

For some reason, a DialogFragment that I've just created won't appear whenever I try to launch it from a click event. Why does the dialog not have a view, when my view has been clearly set builder.setView(rootView)?

Fragment does not have a view

click event to launch DialogFragment

    holder.myButton.setOnClickListener {
        val dialog = MyDialog()
        val manager = (holder.itemView.context as FragmentActivity).supportFragmentManager
        dialog.show(manager, "example")
    }

DialogFragment

class MyDialog : DialogFragment() {
    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        LayoutInflater.from(requireContext())

        val builder = AlertDialog.Builder(activity)
        val rootView = LayoutInflater.from(requireContext()).inflate(R.layout.dialog_sample, null, false)


        lateinit var tabLayout: TabLayout
        lateinit var viewPager: ViewPager

        builder.setIconAttribute(R.attr.myImg)
        builder.setTitle("My Program")
        builder.setView(rootView)
        builder.setMessage("My Message")
        builder.setPositiveButton(getString(R.string.ok)) { dialog, _ -> dialog.dismiss() }

        tabLayout = rootView.findViewById(R.id.tabLayout)
        viewPager = rootView.findViewById(R.id.masterViewPager)

        val adapter = CustomAdapter(childFragmentManager)
        adapter.addFragment("Boy", CustomFragment.createInstance("John"))
        adapter.addFragment("Girl", CustomFragment.createInstance("Stacy"))
        adapter.addFragment("Robot", CustomFragment.createInstance("Aeon"))
        viewPager.adapter = adapter
        tabLayout.setupWithViewPager(viewPager)

       // return builder.create()
        return builder.show()
    }
}

dialog_sample.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <com.google.android.material.tabs.TabLayout
        android:id="@+id/tabLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <androidx.viewpager.widget.ViewPager
        android:id="@+id/masterViewPager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</LinearLayout>

CustomFragment class

class CustomFragment : androidx.fragment.app.Fragment() {
    private var mText = ""

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val v = inflater.inflate(R.layout.fragment_sample, container, false)
        (v.findViewById(R.id.textView_sample) as TextView).text = mText
        return v
    }

    companion object {
        fun createInstance(txt: String): CustomFragment {
            val fragment = CustomFragment()
            fragment.mText = txt
            return fragment
        }
    }
}

Logcat

    java.lang.IllegalStateException: Fragment does not have a view
        at androidx.fragment.app.Fragment$3.onFindViewById(Fragment.java:2396)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:869)
        at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1229)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1295)
        at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:686)
        at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2057)
        at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1847)
        at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1802)
        at androidx.fragment.app.FragmentManagerImpl.execSingleAction(FragmentManagerImpl.java:1679)
        at androidx.fragment.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:536)
        at androidx.fragment.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:148)
        at androidx.viewpager.widget.ViewPager.populate(ViewPager.java:1244)
        at androidx.viewpager.widget.ViewPager.populate(ViewPager.java:1092)
        at androidx.viewpager.widget.ViewPager.onMeasure(ViewPager.java:1622)
        at android.view.View.measure(View.java:23169)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        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:23169)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.view.View.measure(View.java:23169)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.view.View.measure(View.java:23169)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        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 com.android.internal.widget.AlertDialogLayout.onMeasure(AlertDialogLayout.java:71)
        at android.view.View.measure(View.java:23169)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.view.View.measure(View.java:23169)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.view.View.measure(View.java:23169)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at com.android.internal.policy.DecorView.onMeasure(DecorView.java:716)
        at android.view.View.measure(View.java:23169)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2718)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1545)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1855)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1460)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7183)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:949)
        at android.view.Choreographer.doCallbacks(Choreographer.java:761)
        at android.view.Choreographer.doFrame(Choreographer.java:696)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:935)
        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:6669)
E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
I/Process: Sending signal. PID: 4867 SIG: 9
Application terminated.

adapter class

class MyRVAdapter(private val itemsList: ArrayList<Item>) : RecyclerView.Adapter<MyRVAdapter.ViewHolder>() {
    override fun getItemCount(): Int {
        return itemsList.size
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        // Button click listener
        holder.myButton.setOnClickListener {
            val dialog = CustomFragment()
            val manager = (holder.itemView.context as FragmentActivity).supportFragmentManager
            dialog.show(manager, dialog.tag)
        }
     }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val v = LayoutInflater.from(parent.context).inflate(R.layout.my_cv, parent, false)
        return ViewHolder(v)
    }

    class ViewHolder (itemView : View):RecyclerView.ViewHolder(itemView) {
        val mCV = itemView.findViewById<CardView>(R.id.cv_main)!!

        val myButton = itemView.findViewById<Button>(R.id.btn_main)!!
    }

    class MyViewPagerAdapter(manager: androidx.fragment.app.FragmentManager) : androidx.fragment.app.FragmentPagerAdapter(manager){
        private val fragmentList : MutableList<androidx.fragment.app.Fragment> = java.util.ArrayList()
        private val titleList : MutableList<String> = java.util.ArrayList()

        override fun getItem(position: Int): androidx.fragment.app.Fragment {
            return fragmentList[position]
        }

        override fun getCount(): Int {
            return fragmentList.size
        }

        fun addFragment(fragment: androidx.fragment.app.Fragment, title: String){
            fragmentList.add(fragment)
            titleList.add(title)
        }

        override fun getPageTitle(position: Int): CharSequence? {
            return titleList[position]
        }
    }
}

回答1:

If you override onCreateDialog with AlertDialog instead of overriding onCreateView, you shall bump into IllegalStateException.

please checkout the link to solve