AccountListFragment: use ViewModel

import android.accounts.Account

import android.accounts.AccountManager

import android.accounts.OnAccountsUpdateListener

import android.app.Application

import android.content.Context

import android.content.Intent

import android.os.Bundle

import android.widget.AdapterView

import android.widget.ArrayAdapter

import androidx.fragment.app.ListFragment

import androidx.loader.app.LoaderManager

import androidx.loader.content.AsyncTaskLoader

import androidx.loader.content.Loader

import androidx.lifecycle.AndroidViewModel

import androidx.lifecycle.MutableLiveData

import androidx.lifecycle.Observer

import androidx.lifecycle.ViewModelProviders

import at.bitfire.davdroid.R

import kotlinx.android.synthetic.main.account_list_item.view.*

class AccountListFragment: ListFragment(), LoaderManager.LoaderCallbacks<Array<Account>> {

class AccountListFragment: ListFragment() {

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {

        listAdapter = AccountListAdapter(requireActivity())

        val model = ViewModelProviders.of(this).get(Model::class.java)

        model.accounts.observe(this, Observer { accounts ->

            val adapter = listAdapter as AccountListAdapter

            adapter.clear()

            adapter.addAll(*accounts)

        })

        return inflater.inflate(R.layout.account_list, container, false)

    }

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

        super.onViewCreated(view, savedInstanceState)

        LoaderManager.getInstance(this).initLoader(0, arguments, this)

        listView.choiceMode = AbsListView.CHOICE_MODE_SINGLE

        listView.onItemClickListener = AdapterView.OnItemClickListener { _, _, position, _ ->

    }

    // loader

    // list adapter

    override fun onCreateLoader(id: Int, args: Bundle?) =

            AccountLoader(requireActivity())

    class AccountListAdapter(

            context: Context

    ): ArrayAdapter<Account>(context, R.layout.account_list_item) {

    override fun onLoadFinished(loader: Loader<Array<Account>>, accounts: Array<Account>) {

        val adapter = listAdapter as AccountListAdapter

        adapter.clear()

        adapter.addAll(*accounts)

    }

        override fun getView(position: Int, _v: View?, parent: ViewGroup?): View {

            val account = getItem(position)!!

    override fun onLoaderReset(loader: Loader<Array<Account>>) {

        (listAdapter as AccountListAdapter).clear()

            val v = _v ?: LayoutInflater.from(context).inflate(R.layout.account_list_item, parent, false)

            v.account_name.text = account.name

            return v

        }

    }

    class AccountLoader(

            context: Context

    ): AsyncTaskLoader<Array<Account>>(context) {

        private val accountManager = AccountManager.get(context)!!

        private var listener: OnAccountsUpdateListener? = null

    class Model(

            application: Application

    ): AndroidViewModel(application), OnAccountsUpdateListener {

        override fun onStartLoading() {

            if (listener == null) {

                listener = OnAccountsUpdateListener { onContentChanged() }

                accountManager.addOnAccountsUpdatedListener(listener, null, false)

            }

        val accounts = MutableLiveData<Array<out Account>>()

            forceLoad()

        private val accountManager = AccountManager.get(getApplication())!!

        init {

            accountManager.addOnAccountsUpdatedListener(this, null, true)

        }

        override fun onReset() {

            listener?.let {

                try {

                    accountManager.removeOnAccountsUpdatedListener(it)

                } catch(ignored: IllegalArgumentException) {}

                listener = null

            }

        override fun onCleared() {

            accountManager.removeOnAccountsUpdatedListener(this)

        }

        override fun loadInBackground(): Array<Account> =

        override fun onAccountsUpdated(newAccounts: Array<out Account>) {

            val context = getApplication<Application>()

            accounts.postValue(

                    AccountManager.get(context).getAccountsByType(context.getString(R.string.account_type))

            )

        }

    // list adapter

    class AccountListAdapter(

            context: Context

    ): ArrayAdapter<Account>(context, R.layout.account_list_item) {

        override fun getView(position: Int, _v: View?, parent: ViewGroup?): View {

            val account = getItem(position)!!

            val v = _v ?: LayoutInflater.from(context).inflate(R.layout.account_list_item, parent, false)

            v.account_name.text = account.name

            return v

        }

    }

}

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