A class to make simple the use of DialogFragment with AlertDialog. You can set a few properties directly, or provide a delegate and deal with Builder directly. *NEW*: This now supports instance state restoration. Assigning a delegate is now deprecated. Instead, implement a provideDelegate() function. For example, Use ActivityDelegatingDialogFrag…

DialogListPicker.kt

package letstwinkle.com.twinkle.util

import android.annotation.SuppressLint
import android.os.Bundle
import android.support.v4.os.ConfigurationCompat
import android.text.Spannable
import android.text.SpannableStringBuilder
import android.text.style.ImageSpan
import android.view.View
import android.view.ViewTreeObserver
import android.view.inputmethod.EditorInfo
import android.widget.*
import letstwinkle.com.twinkle.*
import letstwinkle.com.twinkle.model.Interests
import letstwinkle.com.twinkle.widget.StableArrayAdapter

private const val tag_ = "DialogListPicker"
internal class DialogListPicker
{
    companion object {
        fun forOccupation(occus: List<String>, defaultIndex: Int = -1): SimpleDialogFragment
        {
            val frag = forOccupation(defaultIndex)
            frag.arguments.putStringArray("items", occus.toTypedArray())
            return frag
        }

        fun forOccupation(defaultIndex: Int = -1): SimpleDialogFragment {
            return makeFragment(Dialogs.ChooseOccupation, defaultIndex)
        }

        @SuppressLint("InflateParams")
        fun forEducationSite(sites: List<String>, defaultIndex: Int = -1): SimpleDialogFragment
        {
            val frag = forEducationSite(defaultIndex)
            frag.arguments.putStringArray("items", sites.toTypedArray())
            return frag
        }

        fun forEducationSite(defaultIndex: Int = -1): SimpleDialogFragment {
            return makeFragment(Dialogs.ChooseEduSite, defaultIndex)
        }

        @SuppressLint("InflateParams")
        fun forInterests(excluding: ArrayList<Int> = arrayListOf()): SimpleDialogFragment
        {
            return makeFragment(Dialogs.ChooseInterest, -1, excluding)
        }

        private fun makeFragment(id: Int, defaultIndex: Int = -1, excluding: ArrayList<Int>? = null)
            : SimpleDialogFragment
        {
            val frag = ListPickerDialogFragment()
            frag.ID = id
            frag.canceledOnTouchOutside = false
            val args = Bundle()
            args.putInt("default", defaultIndex)
            args.putIntegerArrayList("exclude", excluding)
            frag.arguments = args
            return frag
        }

    }
}

internal class ListPickerDialogFragment() : SimpleDialogFragment(), SearchView.OnQueryTextListener {

    private var defaultIndex = Adapter.NO_SELECTION
    private lateinit var adapter: StableArrayAdapter<String>

    override fun createCustomView(): View? {
        return this.activity.layoutInflater.inflate(R.layout.dialog_searchable_rv, null)
    }

    override fun onStart() {
        super.onStart()
        defaultIndex = this.arguments.getInt("default")

        val adapter: StableArrayAdapter<String>
        if (this.ID == Dialogs.ChooseInterest) {
            val excludeList = this.arguments.getIntegerArrayList("exclude") ?: emptyList<Int>()
            val entries = Interests.getStableEntries(excludeList)
            adapter = StableArrayAdapter(android.R.layout.simple_list_item_checked,
                                         this.activity,
                                         entries)
        } else if (this.arguments.getStringArray("items") != null) {
            adapter = StableArrayAdapter(this.activity,
                                         android.R.layout.simple_list_item_checked,
                                         this.arguments.getStringArray("items"))
        } else if (this.ID == Dialogs.ChooseEduSite) {
            val entries = Global.splitRawIntoArray(R.raw.schools)
            adapter = StableArrayAdapter(this.activity,
                                         android.R.layout.simple_list_item_checked,
                                         entries)
        } else if (this.ID == Dialogs.ChooseOccupation) {
            val entries = Global.splitRawIntoArray(R.raw.occupations)
            adapter = StableArrayAdapter(this.activity,
                                         android.R.layout.simple_list_item_checked,
                                         entries)
        } else {
            throw IllegalArgumentException("Invalid Dialog ID for ListPickerDialogFragment")
        }

        this.adapter = adapter
        attachDelayer(adapter.filter)

        val listView = this.dialog.findViewById<ListView>(R.id.results)
        listView.adapter = adapter
        listView.tag = this.ID
        // call the listener, but enforce that list is no longer clickable (could also dismiss dlog here)
        listView.onItemClickListener = AdapterView.OnItemClickListener { parent, view, pos, id ->
            listView.isEnabled = false
            val event = AdapterViewOnItemClick(parent, view, pos, id)
            TwinkleApplication.instance.ottobus.post(event)
        }
        if (defaultIndex > 0) {
            listView.setItemChecked(defaultIndex, true)
            listView.setSelection(defaultIndex)
        }
        listView.viewTreeObserver.addOnGlobalLayoutListener(object : ViewTreeObserver.OnGlobalLayoutListener {
            override fun onGlobalLayout() {
                if (listView.height > 0) {
                    listView.layoutParams.height = listView.height
                    listView.viewTreeObserver.removeOnGlobalLayoutListener(this)
                }
            }
        })

        // Edu picker: if Hindi: all schools shown in English, so change keyboard
        if (ID == Dialogs.ChooseEduSite) {
            val searchView = this.dialog.findViewById<SearchView>(R.id.searchView)
            val ctx = this.dialog.context
            if (ConfigurationCompat.getLocales(ctx.resources.configuration).get(0).language == "hi") {
                searchView.imeOptions = searchView.imeOptions or EditorInfo.IME_FLAG_FORCE_ASCII
            }
        }

        val searchView = this.dialog.findViewById<SearchView>(R.id.searchView)
        searchView?.setOnQueryTextListener(this)
        try {
            val ssb = SpannableStringBuilder("   ")
            ssb.setSpan(ImageSpan(searchView?.context, R.drawable.abc_ic_search_api_material), 1, 2, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
            searchView?.queryHint = ssb
        } catch (ex: Exception) {
        }

    }

    // OnQueryTextListener
    override fun onQueryTextSubmit(query: String?): Boolean {
        return true
    }

    override fun onQueryTextChange(newText: String?): Boolean {
        adapter.filter?.filter(newText)
        return true
    }
}

private fun attachDelayer(filter: Filter) {
    ignoreExceptions {
        val delayerClass = Class.forName("android.widget.Filter\$Delayer", true, filter.javaClass.classLoader)
        val setDelayer = Filter::class.java.getDeclaredMethod("setDelayer", delayerClass)
        setDelayer.invoke(filter, MyDelayerInvocationHandler.proxy())
    }
}

SimpleDialogFragment.kt

package letstwinkle.com.twinkle.util

import android.app.*
import android.content.DialogInterface
import android.content.DialogInterface.*
import android.os.Bundle
import android.support.annotation.LayoutRes
import android.support.annotation.StringRes
import android.util.Log
import android.view.View
import android.view.ViewGroup

private const val tag_ = "SimpleDialogFragment"

open internal class SimpleDialogFragment : DialogFragment(), OnClickListener, OnCancelListener, OnDismissListener {
    var ID: Int = -1
    @StringRes var title: Int? = null
    @StringRes var message:  Int? = null
    @StringRes var positiveLabel: Int? = null
    @StringRes var negativeLabel: Int? = null
    @StringRes var neutralLabel: Int? = null
    var listItems: Array<CharSequence>? = null
    var messageCS: CharSequence? = null // takes precedecnce
    var canceledOnTouchOutside = true
    protected var delegate: SimpleDialogDelegate? = null
    protected var destroyed = false

    val customView: View?
        get() = this.dialog.findViewById<ViewGroup>(android.R.id.custom)?.getChildAt(0)

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        savedInstanceState?.let {
            // all of our public properties won't have any value, but would have been stashed
            // into the arguments in onSaveInstanceState
            ID = savedInstanceState.getInt("id")
            title = savedInstanceState.get("title") as Int?
            message = savedInstanceState.get("msg") as Int?
            positiveLabel = savedInstanceState.get("pos") as Int?
            negativeLabel = savedInstanceState.get("neg") as Int?
            neutralLabel = savedInstanceState.get("neut") as Int?
            listItems = savedInstanceState.getCharSequenceArray("list")
            messageCS = savedInstanceState.getCharSequence("msgCS")
            canceledOnTouchOutside = savedInstanceState.getBoolean("coto")
        }
    }

    override fun onAttach(activity: Activity) {
        super.onAttach(activity)
        Log.d("SimpleDialogFragment", "onAttach checking provideDelegate")
        delegate = provideDelegate()
        Log.d("SimpleDialogFragment", "onAttach found delegate: ${delegate != null}")
    }

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        val builder = AlertDialog.Builder(this.activity)
        title?.let {builder.setTitle(it)}
        message?.let {builder.setMessage(it)}
        messageCS?.let {builder.setMessage(it)}
        positiveLabel?.let {builder.setPositiveButton(it, this)}
        negativeLabel?.let {builder.setNegativeButton(it, this)}
        neutralLabel?.let {builder.setNeutralButton(it, this)}
        createCustomView()?.let {
            Log.d(tag_, "onCreateDialog: createCustomView")
            builder.setView(it)
        }
        listItems?.let {builder.setItems(listItems, this)}
        delegate?.onCreateDialog(builder, this)
        val dialog = builder.create()
        if (!canceledOnTouchOutside)
            dialog.setCanceledOnTouchOutside(false)
        return dialog
    }

    override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)
        outState.putInt("id", ID)
        title?.let {outState.putInt("title", it)}
        message?.let {outState.putInt("msg", it)}
        positiveLabel?.let {outState.putInt("pos", it)}
        negativeLabel?.let {outState.putInt("neg", it)}
        neutralLabel?.let {outState.putInt("neut", it)}
        listItems?.let {outState.putCharSequenceArray("list", it)}
        messageCS?.let {outState.putCharSequence("msgCS", it)}
        outState.putBoolean("coto", canceledOnTouchOutside)
    }

    override fun onDestroy() {
        super.onDestroy()
        delegate = null
        destroyed = true
    }

    override fun onClick(dialog: DialogInterface?, which: Int) {
        delegate?.simpleDialogClicked(this, which)
    }

    override fun onCancel(dialog: DialogInterface?) {
        super.onCancel(dialog)
        delegate?.simpleDialogCanceled(this)
    }

    override fun onDismiss(dialog: DialogInterface?) {
        super.onDismiss(dialog)
        delegate?.simpleDialogDismissed(this)
    }

    override fun onStart() {
        super.onStart()
        delegate?.simpleDialogStarted(this)
    }

    override fun show(manager: FragmentManager, tag: String) {
        // to do without try-catch requires API 26 FragmentManager#isStateSaved
        try {
            super.show(manager, tag)
        } catch (ex: IllegalStateException) {
        }
    }

    // Non-overrides

    open fun provideDelegate() : SimpleDialogDelegate? = null

    /**
     * Override this to establish a view as the AlertDialog's 'custom' view.
     */
    open fun createCustomView(): View? = null

    fun showAllowingStateLoss(fragMgr: FragmentManager, tag: String) {
        if (!fragMgr.isDestroyed)
            fragMgr.beginTransaction().add(this, tag).commitAllowingStateLoss()
    }
}

internal interface SimpleDialogDelegate {
    fun onCreateDialog(builder: AlertDialog.Builder, frag: SimpleDialogFragment) { onCreateDialog(builder)}
    fun onCreateDialog(builder: AlertDialog.Builder) {}
    fun simpleDialogClicked(dlog: SimpleDialogFragment, which: Int) {}
    fun simpleDialogCanceled(dlog: SimpleDialogFragment) {}
    fun simpleDialogDismissed(dlog: SimpleDialogFragment) {}
    fun simpleDialogStarted(dlog: SimpleDialogFragment) {}
}

open internal class ActivityDelegatingDialogFragment : SimpleDialogFragment() {
    override fun onAttach(activity: Activity) {
        super.onAttach(activity)
        if (activity is SimpleDialogDelegate) {
            delegate = activity
            Log.d("ADDF", "found activity delegate")
        }
        else
            throw IllegalStateException("ActivityDelegatingDialogFragment must be attached to a context that implements SimpleDialogDelegate")
    }
}

internal class SimpleLayoutDialogFragment : ActivityDelegatingDialogFragment() {
    override fun createCustomView(): View? {
        val layoutRes = this.arguments.getInt(LAYOUT_RES)
        return this.activity.layoutInflater.inflate(layoutRes, null)
    }

    companion object {
        private const val LAYOUT_RES = "layres"
        fun newInstance(@LayoutRes layoutRes: Int): SimpleLayoutDialogFragment {
            val frag = SimpleLayoutDialogFragment()
            val args = Bundle()
            args.putInt(LAYOUT_RES, layoutRes)
            frag.arguments = args
            return frag
        }
    }
}