Привет) Я новичок в Android dev. Я делаю приложение с контролем тестов.
Вот мое задание:
class TestActivity : AppCompatActivity() {
private lateinit var urlToTest: String
private val list = ArrayList<Test>()
private var randomList = ArrayList<Test>()
private var currentItem = 0
private var fragmentsList = ArrayList<Fragment>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_test)
val title = getIntent().getStringExtra("TestTitle")
setTitle(title)
urlToTest = "http://sasmobile.ru" + getIntent().getStringExtra("urlToJson") + getIntent().getStringExtra("jsonName")
val recView = findViewById<RecyclerView>(R.id.testRecyclerView)
recView.layoutManager = LinearLayoutManager(this, RecyclerView.HORIZONTAL, false)
val connector = Connector().isConnectedToNetwork(this)
val submitButton : Button = findViewById(R.id.submitButton)
if (connector) {
AsyncTaskHandler().execute(urlToTest)
submitButton.setOnClickListener{
if (currentItem<9) {
currentItem += 1
testAdapterItemClick(randomList[currentItem], currentItem)
}
if (currentItem==9){
checkTest(randomList)
}
}
}
else{
submitButton.visibility=View.INVISIBLE
openAlertDialog()
}
}
private fun openAlertDialog(){
val dialogBuilder = AlertDialog.Builder(this)
val connector = Connector().isConnectedToNetwork(this)
dialogBuilder.setMessage("Check your Internet connection")
.setCancelable(false)
.setPositiveButton("Try again", DialogInterface.OnClickListener{
dialog, id -> if (connector) {
dialog.cancel()
AsyncTaskHandler().execute(urlToTest)
}
else openAlertDialog()
})
val alertBox = dialogBuilder.create()
alertBox.setTitle("Ooops")
alertBox.show()
}
private fun checkTest(testList: ArrayList<Test>){
val recView : RecyclerView = findViewById(R.id.testRecyclerView)
for (i in 0 until testList.size) {
val viewHolder = recView.findViewHolderForAdapterPosition(i) as RecyclerView.ViewHolder
val view = viewHolder.itemView
val cardView = view.findViewById<CardView>(R.id.testCardView)
if (testList[i].examination) {
cardView.setCardBackgroundColor(getResources().getColor(R.color.colorTrue))
}
if (!testList[i].examination){
cardView.setCardBackgroundColor(getResources().getColor(R.color.colorFalse))
}
}
}
private fun testAdapterItemClick(item: Test, currI : Int) {
val fT: FragmentTransaction = supportFragmentManager.beginTransaction()
currentItem = currI
val recView : RecyclerView = findViewById(R.id.testRecyclerView)
val layoutManager = LinearLayoutManager(this, RecyclerView.HORIZONTAL, false)
layoutManager.scrollToPositionWithOffset(currentItem-3, 0)
recView.layoutManager=layoutManager
val submitButton : Button = findViewById(R.id.submitButton)
if (currentItem<9){
submitButton.text="Next Questions"
}
if (currentItem==9){
submitButton.text="Finish Test"
}
if (item.typeQuestion == "input") {
val bundle = Bundle()
bundle.putParcelable("ITEM", item)
if(!item.questionImageSrc.isNullOrEmpty())
bundle.putString("IMAGE_KEY", item.questionImageSrc)
fragmentsList[currentItem].setArguments(bundle)
if (!fragmentsList[currentItem].isAdded())
fT.add(R.id.frameLayout, fragmentsList[currentItem])
if (fragmentsList[currentItem].isAdded())
fT.replace(R.id.frameLayout, fragmentsList[currentItem])
}
if (item.typeQuestion == "singleChoice") {
val bundle = Bundle()
bundle.putParcelable("ITEM", item)
val count = item.singleChoiceAnswers.count()
bundle.putInt("COUNT_KEY", count)
fragmentsList[currentItem].setArguments(bundle)
if (!fragmentsList[currentItem].isAdded())
fT.add(R.id.frameLayout, fragmentsList[currentItem])
if (fragmentsList[currentItem].isAdded())
fT.replace(R.id.frameLayout, fragmentsList[currentItem])
}
if (item.typeQuestion == "multipleChoice") {
val bundle = Bundle()
bundle.putParcelable("ITEM", item)
val count = item.multipleChoiceAnswers.count()
bundle.putInt("COUNT_KEY", count)
fragmentsList[currentItem].setArguments(bundle)
if (!fragmentsList[currentItem].isAdded())
fT.add(R.id.frameLayout, fragmentsList[currentItem])
if (fragmentsList[currentItem].isAdded())
fT.replace(R.id.frameLayout, fragmentsList[currentItem])
}
fT.addToBackStack(null)
fT.commit()
}
inner class AsyncTaskHandler() : AsyncTask<String, String, String>() {
override fun onPreExecute() {
val proggressBar: ProgressBar = findViewById(R.id.progressBarTest)
proggressBar.visibility = View.VISIBLE
super.onPreExecute()
}
override fun doInBackground(vararg params: String?): String {
val res: String
val connection = URL(urlToTest).openConnection() as HttpURLConnection
try {
connection.connect()
res = connection.inputStream.use { it.reader().use { reader -> reader.readText() } }
} finally {
connection.disconnect()
}
return res
}
override fun onPostExecute(result: String?) {
super.onPostExecute(result)
if (progressBarTest.visibility == View.VISIBLE)
progressBarTest.visibility = View.INVISIBLE
jsonResult(result)
}
private fun jsonResult(jsonString: String?) {
val jsonArray = JSONArray(jsonString)
for (i in 0 until jsonArray.length()){
val jsonObject = jsonArray.getJSONObject(i)
val typeQuestion = jsonObject.getString("typeQuestion")
val curentId = jsonObject.optInt("id")
val curentNQ = jsonObject.optString("numberQuestion")
val curentQ = jsonObject.optString("question")
val curentQIS = jsonObject.optString("questionImageSrc")
val curentEx = jsonObject.optBoolean("examination")
if (typeQuestion.contains("multipleChoice")){
val multipleChoiceAnswers = jsonObject.getJSONArray("multipleChoiceAnswers")
val mlist = ArrayList<multipleChoiceAnswers>()
val ilist = ArrayList<inputAnswer>()
val slist = ArrayList<singleChoiceAnswer>()
for (sc in 0 until multipleChoiceAnswers.length()){
val curentMCA = multipleChoiceAnswers.getJSONObject(sc)
val letter = curentMCA.optString("letter")
val text = curentMCA.optString("text")
val correctAnswer = curentMCA.optBoolean("correctAnswer")
val checked = curentMCA.optBoolean("checked")
mlist.add(
multipleChoiceAnswers(
letter,
text,
correctAnswer,
checked
)
)
}
list.add(
Test(
curentId,
curentNQ,
curentQ,
curentQIS,
curentEx,
typeQuestion,
slist,
mlist,
ilist
)
)
}
if (typeQuestion.contains("singleChoice")){
val mlist = ArrayList<multipleChoiceAnswers>()
val ilist = ArrayList<inputAnswer>()
val slist = ArrayList<singleChoiceAnswer>()
val singleChoiceAnswer = jsonObject.getJSONArray("singleChoiceAnswers")
for (sc in 0 until singleChoiceAnswer.length()){
val curentSCA = singleChoiceAnswer.getJSONObject(sc)
val letter = curentSCA.optString("letter")
val text = curentSCA.optString("text")
val correctAnswer = curentSCA.optBoolean("correctAnswer")
val checked = curentSCA.optBoolean("checked")
slist.add(
singleChoiceAnswer(
letter,
text,
correctAnswer,
checked
)
)
}
list.add(
Test(
curentId,
curentNQ,
curentQ,
curentQIS,
curentEx,
typeQuestion,
slist,
mlist,
ilist
)
)
}
if (typeQuestion.contains("input")){
val inputAnswer = jsonObject.getJSONArray("inputAnswer")
val mlist = ArrayList<multipleChoiceAnswers>()
val ilist = ArrayList<inputAnswer>()
val slist = ArrayList<singleChoiceAnswer>()
for (sc in 0 until inputAnswer.length()){
val curentIA = inputAnswer.getJSONObject(sc)
val correctAnswer = curentIA.optString("correctAnswer")
val userAnswer = curentIA.optString("userAnswer")
ilist.add(
inputAnswer(
correctAnswer,
userAnswer
)
)
}
list.add(
Test(
curentId,
curentNQ,
curentQ,
curentQIS,
curentEx,
typeQuestion,
slist,
mlist,
ilist
)
)
}
}
randomList = SubmitTest().getRandomList(list)
fragmentsList= SubmitTest().getFragmentList(randomList)
val adapter =
TestAdapter(randomList) { item, position ->
testAdapterItemClick(item, position)
}
testAdapterItemClick(randomList[currentItem], currentItem)
val recView = findViewById<RecyclerView>(R.id.testRecyclerView)
recView.adapter = adapter
}
}
}
Я получаю тестовые вопросы от JSON я получаю 10 случайных вопросов и только помещаю их в RecyclerView.
это мой адаптер:
class TestAdapter(val test : ArrayList<Test>, private val testAdapterCallback: (Test, Int)-> Unit) : RecyclerView.Adapter<TestAdapter.ViewHolder>(){
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val v = LayoutInflater.from(parent.context).inflate(R.layout.test_view_item, parent, false)
return ViewHolder(v)
}
override fun getItemCount(): Int {
return test.size
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val num : Test = test[position]
holder.textView.text = num.id.toString()
holder.cardView.setOnClickListener(){
testAdapterCallback(num, position)
}
}
inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView){
val cardView = itemView.findViewById<CardView>(R.id.testCardView)
val textView = itemView.findViewById<TextView>(R.id.testTextView)
}
}
Я должен изменить цвет каждого вида карты в конце теста (зеленый, если он правильный, красный, если нет). Как я могу получить ViewHolder из действия и изменить цвет?
Я делаю это так:
private fun checkTest(testList: ArrayList<Test>){
val recView : RecyclerView = findViewById(R.id.testRecyclerView)
for (i in 0 until testList.size) {
val viewHolder = recView.findViewHolderForAdapterPosition(i) as RecyclerView.ViewHolder
val view = viewHolder.itemView
val cardView = view.findViewById<CardView>(R.id.testCardView)
if (testList[i].examination) {
cardView.setCardBackgroundColor(getResources().getColor(R.color.colorTrue))
}
if (!testList[i].examination){
cardView.setCardBackgroundColor(getResources().getColor(R.color.colorFalse))
}
}
}
Но есть ошибка
kotlin.TypeCastException: null cannot be cast to non-null type androidx.recyclerview.widget.RecyclerView.ViewHolder
Заранее спасибо )
PS Извините за мой Engli sh)