Android：向列表中添加一个新项目，并使用Kotlin通过RecyclerView适配器显示它

我有一个片段有一个回收视图。当用户单击片段中的按钮（添加新项目）时，应用程序会将用户（通过意图）带到表单中以填写一些数据

当我单击（添加项）时，它应该将数据添加到数组列表并完成该屏幕。返回片段后，应使用适配器将此数据添加到RecyclerView

这是我的代码：

以下是片段：

private val REQUEST_CODE = 2

internal lateinit var adapter: ShipmentItemAdapter

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

    return inflater!!.inflate(R.layout.fragment_step_three_shipment, container, false)
}

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

    btnAddNewShipmentStep3.setOnClickListener {
        val intent = Intent(context, AddItemActivity::class.java)
        startActivityForResult(intent, REQUEST_CODE)
    }
}

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data);

    val items = ArrayList<ItemsItem>()

    if (requestCode == REQUEST_CODE) {

        adapter = ShipmentItemAdapter(context, items)

        if (resultCode == Activity.RESULT_OK) {
            itemsShipments.visibility = View.VISIBLE
            itemsShipments.layoutManager = LinearLayoutManager(context)
            itemsShipments.setHasFixedSize(true)
            itemsShipments.adapter = adapter

        } else if (resultCode == Activity.RESULT_CANCELED) {
            itemsShipments.visibility = View.GONE
        }
    }
}

private val请求\u code=2
内部lateinit变量适配器：ShipmentItemAdapter
覆盖创建视图（充气机：布局充气机？、容器：视图组？、savedInstanceState:捆绑？）：视图？{
返回充气机！！.充气（R.layout.fragment\u step\u three\u装运，集装箱，错误）
}
覆盖已创建的视图（视图：view？，savedInstanceState:Bundle？）{
super.onViewCreated（视图，savedInstanceState）
btnAddNewShipmentStep3.setOnClickListener{
val intent=intent（上下文，AddItemActivity:：class.java）
startActivityForResult（意图、请求代码）
}
}
重写activityResult（请求代码：Int，结果代码：Int，数据：Intent？）{
super.onActivityResult（请求代码、结果代码、数据）；
val items=ArrayList（）
if（requestCode==请求\代码）{
adapter=ShipmentItemAdapter（上下文，项）
if（resultCode==Activity.RESULT\u确定）{
itemsShipments.visibility=View.VISIBLE
itemsShipments.layoutManager=LinearLayoutManager（上下文）
itemsShipments.setHasFixedSize（true）
itemsShipments.adapter=适配器
}else if（resultCode==Activity.RESULT\u已取消）{
itemsShipments.visibility=View.GONE
}
}
}

以下是活动：

class AddItemActivity : AppCompatActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_add_item_form)

    linPackageAddShipment.setOnClickListener {
        edtPackageAddShipment.requestFocus()
    }

    linPiecesAddShipment.setOnClickListener {
        edtPiecesAddShipment.requestFocus()
    }

    linWeightAddShipment.setOnClickListener {
        edtWeightAddShipment.requestFocus()
    }

    linDescriptionAddShipment.setOnClickListener {
        edtDescriptionAddShipment.requestFocus()
    }


    btnAddItemAddShipment.setOnClickListener {
        val errors = collectData()

        collectData()

        if (errors.isEmpty()) {

            val intent = Intent()
            setResult(Activity.RESULT_OK, intent)
            finish()

        } else {
            val errorBody = errors.map { getString(it) }.joinToString("\n") { it }
            MaterialDialog.Builder(this)
                    .title("Oops")
                    .content(errorBody)
                    .positiveText(R.string.ok)
                    .positiveColor(ContextCompat.getColor(this, R.color.colorPrimary))
                    .onAny({ dialog, _ -> dialog.dismiss() })
                    .show()
        }
    }
  }

  private fun collectData(): ArrayList<Int> {
    val errors = ArrayList<Int>()
    val item = ItemsItem()

    if (edtPackageAddShipment.text.toString().isEmpty()) {
        errors.add(R.string.packages_must_not_be_empty)

    } else {
        item.numberOfPackages = edtPackageAddShipment.text.toString().toInt()
    }

    if (edtPiecesAddShipment.text.toString().isEmpty()) {
        errors.add(R.string.pieces_must_not_be_empty)

    } else {
        item.numberOfPieces = edtPiecesAddShipment.text.toString()
    }

    if (edtWeightAddShipment.text.toString().isEmpty()) {
        errors.add(R.string.weight_must_not_be_empty)

    } else {
        item.weightUnit = edtWeightAddShipment.text.toString().toInt()
    }

    if (edtHeightAddShipment.text.toString().isEmpty()) {
        errors.add(R.string.height_must_not_be_empty)

    } else {
        item.height = edtHeightAddShipment.text.toString()
    }

    if (edtWidthAddShipment.text.toString().isEmpty()) {
        errors.add(R.string.width_must_not_be_empty)

    } else {
        item.width = edtWidthAddShipment.text.toString()
    }
    if (edtLengthAddShipment.text.toString().isEmpty()) {
        errors.add(R.string.length_must_not_be_empty)

    } else {
        item.length = edtLengthAddShipment.text.toString()
    }

    if (edtDescriptionAddShipment.text.toString().isEmpty()) {
        errors.add(R.string.description_must_not_be_empty)

    } else {
        item.description = edtDescriptionAddShipment.text.toString()
    }

    CreateNewShipmentActivity.mainShipment.shipmentObj.items?.add(item)

    return errors
  }

  override fun onBackPressed() {
    setResult(Activity.RESULT_CANCELED)
    super.onBackPressed()
  }
}

class AddItemActivity:AppCompatActivity（）{
重写创建时的乐趣（savedInstanceState:Bundle？）{
super.onCreate（savedInstanceState）
setContentView（R.layout.activity\u add\u item\u表单）
linPackageAddShipment.setOnClickListener{
edtpackeaddshipment.requestFocus（）文件
}
LinpieceAddShipping.setOnClickListener{
edtpagesaddshipping.requestFocus（）
}
LinweightAddShipping.setOnClickListener{
EDTweightAddShipping.requestFocus（）
}
LindescriptionAddShipping.setOnClickListener{
edtDescriptionAddShipment.requestFocus（）文件
}
btnAddItemAddShipment.setOnClickListener{
val errors=collectData（）
收集数据（）
if（errors.isEmpty（））{
val intent=intent（）
setResult（Activity.RESULT_OK，intent）
完成（）
}否则{
val errorBody=errors.map{getString（it）}.joinToString（“\n”）{it}
MaterialDialog.Builder（此）
.标题（“Oops”）
.内容（错误正文）
.positiveText（R.string.ok）
.positiveColor（ContextCompat.getColor（this，R.color.colorPrimary））
.onAny（{dialog，{->dialog.disease（）}）
.show（）
}
}
}
private fun collectData（）：ArrayList{
val errors=ArrayList（）
val item=ItemsItem（）
如果（edtPackageAddShipment.text.toString（）.isEmpty（））{
errors.add（R.string.packages\u不能为空）
}否则{
item.numberOfPackages=edtPackageAddShipment.text.toString（）.toInt（）
}
如果（EDTPieseddShipping.text.toString（）.isEmpty（））{
错误。添加（R.string.pieces\u不能为空）
}否则{
item.numberOfPieces=EDTPieseAndShipping.text.toString（）
}
如果（EDTweightAddShipping.text.toString（）.isEmpty（））{
错误。添加（R.string.weight\u不能为空）
}否则{
item.weightUnit=EDTweightAddShipping.text.toString（）.toInt（）
}
如果（edTheightAddShipping.text.toString（）.isEmpty（））{
错误。添加（R.string.height\u不能为空）
}否则{
item.height=edtheightaddshipping.text.toString（）
}
如果（edtwidthAddShipping.text.toString（）.isEmpty（））{
错误。添加（R.string.width\u不能为空）
}否则{
item.width=EDTwidthAddShipping.text.toString（）
}
如果（edtLengthAdShipment.text.toString（）.isEmpty（））{
错误。添加（R.string.length\u不能为空）
}否则{
item.length=edtlenghthaddshipment.text.toString（）
}
如果（edtDescriptionAddShipment.text.toString（）.isEmpty（））{
错误。添加（R.string.description\u不能为空）
}否则{
item.description=edtDescriptionAddShipment.text.toString（）
}
CreateNewShipmentActivity.MainShipping.shipmentObj.items？添加（项目）
返回错误
}
重写函数onBackPressed（）{
setResult（活动结果\u已取消）
super.onBackPressed（）
}
}

下面是适配器：

class ShipmentItemAdapter internal constructor(private val context: Context, private val items: List<ItemsItem>) : RecyclerView.Adapter<ShipmentItemAdapter.MyViewHolder>() {

  private val inflater: LayoutInflater = LayoutInflater.from(context)


  override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
    val view = inflater.inflate(R.layout.item_shipment_package, parent, false)

    return MyViewHolder(view).listen { pos, type ->
        val item = items[pos]
        val intent = Intent(context, AddItemActivity::class.java)
        startActivity(context, intent, null)
    }
  }


  override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
    holder.namePackageShipmentPackage.text = items[position].description
    holder.quantityPackageShipmentPackage.text = items[position].description
    holder.dimensionPackageHeightShipmentPackage.text = items[position].description
    holder.dimensionPackageWidthShipmentPackage.text = items[position].description
    holder.dimensionPackageLengthShipmentPackage.text = items[position].description

  }

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

  inner class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {

    var namePackageShipmentPackage: AppCompatTextView = itemView.findViewById(R.id.namePackageShipmentPackage)
    var quantityPackageShipmentPackage: AppCompatTextView = itemView.findViewById(R.id.quantityPackageShipmentPackage)
    var dimensionPackageHeightShipmentPackage: AppCompatTextView = itemView.findViewById(R.id.dimensionPackageHeightShipmentPackage)
    var dimensionPackageWidthShipmentPackage: AppCompatTextView = itemView.findViewById(R.id.dimensionPackageWidthShipmentPackage)
    var dimensionPackageLengthShipmentPackage: AppCompatTextView = itemView.findViewById(R.id.dimensionPackageLengthShipmentPackage)


  }

  private fun <T : RecyclerView.ViewHolder> T.listen(event: (position: Int, type: Int) -> Unit): T {
    itemView.setOnClickListener {
        event.invoke(adapterPosition, itemViewType)
    }
    return this
  }

class ShipmentItemAdapter内部构造函数（private-val-context:context，private-val-items:List）：RecyclerView.Adapter（）{
私有val充气器：LayoutInflater=LayoutInflater.from（上下文）
重写CreateViewHolder（父级：ViewGroup，viewType:Int）：MyViewHolder{
val视图=充气机。充气（R.layout.item_Shipping_package，父项，false）
返回MyViewHolder（视图）。侦听{pos，键入->
val项目=项目[pos]
val intent=intent（上下文，AddItemActivity:：class.java）
startActivity（上下文、意图、空）
}
}
覆盖onBindViewHolder（holder:MyViewHolder，位置：Int）{
holder.namePackageShipmentPackage.text=项目[位置]。说明
holder.quantityPackageShipmentPackage.text=项目[位置]。说明
holder.dimensionPackageHeightShipmentPackage.text=项目[位置]。说明
holder.dimensionPackageWidthShipmentPackage.text=项目[位置]。说明
holder.dimensionPackageLengthShipmentPackage.text=项目[位置]。说明
}
重写getItemCount（）：Int{
返回项目。大小
}
内部类MyViewHolder（itemView:View）：RecyclerView.ViewHolder（ite）
class ShipmentObj {
    var items: ArrayList<ItemsItem?>? = null
}


data class ItemsItem(
    var numberOfPieces: String? = null,
    var length: String? = null,
    var description: String? = null,
    var numberOfPackages: Int? = null,
    var number: Int? = null,
    var width: String? = null,
    var height: String? = null,
    var weightUnit: Int? = null
)

val items = ArrayList<ItemsItem>()
adapter = ShipmentItemAdapter(context, items)

 if (errors.isEmpty()) {
        val intent = Intent()
        setResult(Activity.RESULT_OK, intent)
        finish()
 }