In my application I want create custom calendar with RecyclerView.
I write below codes but when show days into recyclerview adapter show me force close error!
My Adapter codes:

class DaysAdapter constructor(val context: Context, private val items: MutableList<DayEntity>) :
    RecyclerView.Adapter<DaysAdapter.ViewHolder>() {

    private val TYPE_HEADER = 0
    private val TYPE_DAY = 1
    private var firstDayDayOfWeek = 0
    private var totalDays = 0

    init {
        firstDayDayOfWeek = items[0].dayOfWeek
        totalDays = items.size
    }

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

    override fun getItemCount() = 7 * 7

    override fun getItemViewType(position: Int): Int {
        return if (isPositionHeader(position)) {
            TYPE_HEADER
        } else {
            TYPE_DAY
        }
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        //New position
        var newPosition = position
        newPosition  = 6 - (newPosition % 7) * 2
        if (totalDays < position - 6 - firstDayDayOfWeek) {
            return
        }
        //Day
        if (!isPositionHeader(newPosition)) {
            if (newPosition - 7 - firstDayDayOfWeek >= 0) {
                holder.dayTxt.text = items[newPosition - 7 - items[0].dayOfWeek].num
                //Holiday
                if (items[newPosition - 7 - firstDayDayOfWeek].isHoliday) {
                    holder.dayTxt.setTextColor(ContextCompat.getColor(context, R.color.red))
                } else {
                    holder.dayTxt.setTextColor(ContextCompat.getColor(context, R.color.black))
                }
            }
        } else {
            //Header
            holder.dayTxt.text = Constants.FIRST_CHAR_OF_DAYS_OF_WEEK_NAME[newPosition]
        }
    }

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val dayTxt = itemView.findViewById(R.id.dayTxt) as TextView

        @SuppressLint("SetTextI18n")
        fun bind() {

        }
    }

    private fun isPositionHeader(position: Int) = position < 7
}

Error Message in Logcat:

java.lang.IndexOutOfBoundsException: Index: 34, Size: 30
        at java.util.ArrayList.get(ArrayList.java:437)
        at myapp.mycharts.calendar_my.utils.pages.month.DaysAdapter.onBindViewHolder(DaysAdapter.kt:53)
        at myapp.mycharts.calendar_my.utils.pages.month.DaysAdapter.onBindViewHolder(DaysAdapter.kt:15)
        at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:7254)
        at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:7337)
        at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:6194)
        at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6460)
        at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6300)
        at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6296)
        at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2330)
        at androidx.recyclerview.widget.GridLayoutManager.layoutChunk(GridLayoutManager.java:572)
        at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1591)
        at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:668)
        at androidx.recyclerview.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:170)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4309)
        at androidx.recyclerview.widget.RecyclerView.onMeasure(RecyclerView.java:3686)
        at android.view.View.measure(View.java:23169)

Show error for this line:

holder.dayTxt.text = items[newPosition - 7 - items[0].dayOfWeek].num

My Fragment codes for fill days entity:

class CalendarMonthFragment : Fragment() {

    private lateinit var binding: FragmentCalendarMonthBinding

    private val utils by lazy { UtilsKotlin.getInstance(requireContext()) }
    private var monthOffset = 0
    private lateinit var persianDate: PersianDate

    private val daysAdapter by lazy { DaysAdapter(requireContext(), daysList) }
    private val daysList = mutableListOf<DayEntity>()

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
        binding = FragmentCalendarMonthBinding.inflate(layoutInflater)
        return binding.root
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        //Utils
        utils.let { utils ->
            //Persian date
            persianDate = utils.today
            //Init days
            arguments?.let {
                monthOffset = it.getInt(Constants.OFFSET_ARGUMENT)
                daysList.addAll(utils.getDays(monthOffset).toMutableList())
            }
        }
        //Days recyclerview
        daysAdapter.notifyDataSetChanged()
        //InitViews
        binding.apply {
            //Recyclerview
            daysRecyclerview.apply {
                layoutManager = GridLayoutManager(requireContext(), 7)
                adapter = daysAdapter
            }
        }
    }
}

How can I fix it and show data into recyclerview ?

CodePudding user response：

You need to add a check for preventing crash for this line holder.dayTxt.text = items[newPosition - 7 - items[0].dayOfWeek].num

val position = newPosition - 7 - items[0].dayOfWeek

if(position != -1 && position < items.size) {
    holder.dayText.text = items[position].num
}

try above code...

CodePudding user response：

IndexOutOfBounds says, that in items there's no element with such position number. At first check if "items" consists any elements, if yes then check if items[0] exists. if yes then you can get result number from val resultPos = newPosition - 7 - items[0].dayOfWeek and the check if items.size > resultPos if yes then you can get this element. I hope it can help you.