Android:在自定义适配器中使用数据绑定时未赋值

Question

我试图将适配器的绑定变量传递给ViewHolder，以便将值传递给适配器中的文本视图，但这些值没有赋值，单击侦听器也不做任何事情。

下面是我的适配器类：

class DoneAppointmentsAdapter(var context: DoneAppointmentsFragment, listener: ContentListener, var arrayList: List<Appointment>) :
    RecyclerView.Adapter<DoneAppointmentsAdapter.ItemHolder>() {

    private val listener: ContentListener = listener
    private var binding: DoneAppointmentsAdapterBinding? = null

    var activity = context
    override fun onCreateViewHolder(
        parent: ViewGroup,
        viewType: Int
    ): ItemHolder {
        val viewHolder = LayoutInflater.from(parent.context)
            .inflate(R.layout.done_appointments_adapter, parent, false)
        binding = DoneAppointmentsAdapterBinding.inflate(LayoutInflater.from(parent.context))
        return ItemHolder(viewHolder,binding, parent.context)
    }

    override fun onBindViewHolder(holder: ItemHolder, position: Int) {
        holder.bind(arrayList, listener)
    }

    override fun getItemCount(): Int {
        return arrayList.size
    }

    class ItemHolder(view: View, var binding: DoneAppointmentsAdapterBinding?, val context: Context) : RecyclerView.ViewHolder(view) {

        fun bind(listOfData: List<Appointment>, listener: ContentListener) {
            val dataListItem = listOfData[adapterPosition]

            binding?.donePatientItemName?.text = "${dataListItem.patientName}"
            binding?.donePatientItemTime?.text = "Some date"

            binding?.donePatientItemPatientInfo?.setOnClickListener {
                tempAppointmentId = dataListItem.id
                listener.onPatientHistoryViewClicked(dataListItem.requestedBy)
            }

            binding?.donePatientItemReviewCase?.setOnClickListener {
                amendPrescriptionWarning(dataListItem,context)
            }

            binding.donePatientItemViewCase.setOnClickListener {
                startPreview(dataListItem)
            }
        }
    }
}

Answer 1

你在onCreateViewHolder里搞砸了。您已经创建了两次视图，一次是使用LayoutInflater.from(parent.context)，一次是使用DoneAppointmentsAdapterBinding.inflate。在本例中应该只有一个DoneAppointmentsAdapterBinding。

class DoneAppointmentsAdapter(var context: DoneAppointmentsFragment, listener: ContentListener, var arrayList: List<Appointment>) :
    RecyclerView.Adapter<DoneAppointmentsAdapter.ItemHolder>() {
    private val listener: ContentListener = listener

    override fun onCreateViewHolder(
        parent: ViewGroup,
        viewType: Int
    ): ItemHolder {
        val binding = DoneAppointmentsAdapterBinding.inflate(LayoutInflater.from(parent.context))
        return ItemHolder(binding)
    }

    override fun onBindViewHolder(holder: ItemHolder, position: Int) {
        holder.bind(arrayList, listener)
    }

    override fun getItemCount(): Int {
        return arrayList.size
    }

    class ItemHolder (var binding: DoneAppointmentsAdapterBinding) : RecyclerView.ViewHolder(binding.root) {
        fun bind(listOfData: List<Appointment>, listener: ContentListener) {
            val dataListItem = listOfData[adapterPosition]
            binding.donePatientItemName.text = "${dataListItem.patientName}"
            binding.donePatientItemTime.text = "Some date"
            binding.donePatientItemPatientInfo.setOnClickListener {
                tempAppointmentId = dataListItem.id
                listener.onPatientHistoryViewClicked(dataListItem.requestedBy)
            }
            binding.donePatientItemReviewCase.setOnClickListener {
                amendPrescriptionWarning(dataListItem,binding.donePatientItemReviewCase.context)
            }
            binding.donePatientItemViewCase.setOnClickListener {
                startPreview(dataListItem)
            }
        }
    }
}

应该是这样的。我还从ItemHolder中删除了多余的无用参数。为了弄清楚，你的代码的问题是RecyclerView.ViewHolder(view)，当你在binding上做所有的动作和事情的时候，你传递的是view，这是View的两个不同的实例。这应该用上面的代码来修复。