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27
4
我的Recyclerview的自定义适配器有问题。
我试图在一个回收站 View 中显示两个具有不同数据源的不同 View 。
在我进行一些更改之前，它工作得很好，现在却变成了异常(exception)。
直到 notifyDataSetChanged()函数运行正常!
当Holder.txtDelete.onClick或holder.txtEdit.onClick函数触发时，将发生崩溃!
我搜索了很多，但找不到解决方案。感谢您的帮助
我的自定义适配器:
import android.app.Activity
import android.content.Context
import android.content.DialogInterface
import android.content.Intent
import android.os.Vibrator
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.*
import androidx.cardview.widget.CardView
import androidx.recyclerview.widget.RecyclerView
import artemis.team.picandtext.*
import com.squareup.picasso.Picasso
import org.jetbrains.anko.alert
import org.jetbrains.anko.sdk27.coroutines.onClick
import java.util.*
class RecAdapter(
context: Context,
activity: Activity,
grplist: MutableList<GrpsValues> = mutableListOf(),
itemslist: MutableList<ItemsValues> = mutableListOf()
) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
private var context: Context? = null
private var activity: Activity? = null
private var grpList = mutableListOf<GrpsValues>()
private var itemsList = mutableListOf<ItemsValues>()
private lateinit var tts: TextToSpeech
private var voiceText = "Text not found!"
private var voiceLocale = "en-US"
private var mode = 0
private var itemsSize = 0
private var groupsSize = 0
private val ITEM = 100
private val GROUP = 200
private var HOLDER = GROUP
init {
this.activity = activity
this.context = context
this.grpList = grplist
this.itemsList = itemslist
itemsSize = itemsList.size
groupsSize = grpList.size
}
override fun getItemCount(): Int {
return (itemsList.size + grpList.size)
} // getItemCount
override fun onBindViewHolder(recHolder: RecyclerView.ViewHolder, pos: Int) {
Mode()
if (mode == ITEM && HOLDER == ITEM) {
val holder = recHolder as ItemsViewHolder
if (itemsList.size > 0) {
val position = pos - grpList.size
Picasso.get()
.load(itemsList[position].url)
.error(R.drawable.empty)
.into(holder.image)
holder.title.text = itemsList[position].title
holder.txtID.text = itemsList[position].id
holder.grpID.text = itemsList[position].grpID
val grpID = holder.grpID.text.toString()
lateinit var dialog: DialogInterface
holder.layout.onClick {
(context!!.getSystemService(Context.VIBRATOR_SERVICE) as Vibrator?)!!.vibrate(30)
dialog = context!!.alert {
val view = activity!!.layoutInflater.inflate(R.layout.dialog_item_details, null)
val prgDatabase = PrgDatabase(context)
val value = prgDatabase.ItemsFind(holder.txtID.text.toString())
view.findViewById<TextView>(R.id.TxtText).text = value.title
Picasso.get()
.load(value.url)
.error(R.drawable.empty)
.into(view.findViewById<ImageView>(R.id.imageView))
customView = view
}.show()
}
holder.txtDelete.onClick {
(context!!.getSystemService(Context.VIBRATOR_SERVICE) as Vibrator?)!!.vibrate(30)
context!!.alert {
title = "ItemsDelete"
message = "ItemsDelete item from the list?"
positiveButton("Yup") {
val prgDatabase = PrgDatabase(context)
prgDatabase.ItemsDelete(holder.txtID.text.toString())
itemsList = PrgDatabase(context).ItemsGetAll(grpID)
this@RecAdapter.notifyDataSetChanged()
it.dismiss()
}
negativeButton("NO") {
it.dismiss()
}
}.show()
}
holder.txtEdit.onClick {
(context!!.getSystemService(Context.VIBRATOR_SERVICE) as Vibrator?)!!.vibrate(30)
dialog = context!!.alert {
val view = activity!!.layoutInflater.inflate(R.layout.dialog_items, null)
view.findViewById<Button>(R.id.BTNsaveID).text = "Save changes"
val prgDatabase = PrgDatabase(context)
val adapter = ArrayAdapter<String>(
context!!,
android.R.layout.simple_spinner_item,
context!!.resources.getStringArray(
R.array.langueges
)
)
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
view.findViewById<Spinner>(R.id.SpLangsID).adapter = adapter
val value = prgDatabase.ItemsFind(holder.txtID.text.toString())
view.findViewById<EditText>(R.id.ETtitleID).setText(value.title)
view.findViewById<EditText>(R.id.ETurlID).setText(value.url)
view.findViewById<Spinner>(R.id.SpLangsID).setSelection(
when (value.local) {
"English" -> 0
"Russian" -> 1
"Turkish" -> 2
"French" -> 3
"German" -> 4
"Italian" -> 5
"Korean" -> 6
else -> 0
}
)
view.findViewById<Button>(R.id.BTNsaveID).onClick {
if (view.findViewById<EditText>(R.id.ETtitleID).text.isNotEmpty()
&& view.findViewById<EditText>(R.id.ETurlID).text.isNotEmpty()
) {
val value = ItemsValues(
title = view.findViewById<EditText>(R.id.ETtitleID).text.toString(),
url = view.findViewById<EditText>(R.id.ETurlID).text.toString(),
id = holder.txtID.text.toString(),
grpID = grpID,
local = view.findViewById<Spinner>(R.id.SpLangsID).selectedItem.toString()
)
prgDatabase.ItemsUpdate(
value
)
itemsList[position] = value
dialog.dismiss()
this@RecAdapter.notifyDataSetChanged()
this@RecAdapter.notifyItemChanged(position)
}// if
} // btn on click
customView = view
}.show()
} // on click
}
} // if Items
else if (mode == GROUP && HOLDER == GROUP) {
val holder = recHolder as GrpsViewHolder
if (grpList.size > 0) {
val position = pos
holder.titleGrp.text = grpList[position].title
holder.txtItemIDGrp.text = grpList[position].id
holder.txtParentGrpIDGrp.text = grpList[position].parent
holder.layoutGrp.onClick {
val intent = Intent(context, MainActivity::class.java)
intent.putExtra("GrpID", holder.txtItemIDGrp.text.toString())
intent.putExtra("GrpTitle", grpList[position].title)
activity!!.startActivity(intent)
}
holder.txtDeleteGrp.onClick {
(context!!.getSystemService(Context.VIBRATOR_SERVICE) as Vibrator?)!!.vibrate(30)
context!!.alert {
title = "Delete"
message = """
Delete Group from the list?
* With delete this group, all it's words and pictures will be removed!
""".trimIndent()
positiveButton("Yup") {
val prgDatabase = PrgDatabase(context)
prgDatabase.GrpsDelete(holder.txtItemIDGrp.text.toString())
grpList = PrgDatabase(context).GrpsGetAll(grpList[position].parent)
this@RecAdapter.notifyItemRemoved(position)
this@RecAdapter.notifyDataSetChanged()
it.dismiss()
}
negativeButton("NO") {
it.dismiss()
}
}.show()
}
lateinit var dialog: DialogInterface
holder.txtEditGrp.onClick {
(context!!.getSystemService(Context.VIBRATOR_SERVICE) as Vibrator?)!!.vibrate(30)
dialog = context!!.alert {
val view = activity!!.layoutInflater.inflate(R.layout.dialog_grps, null)
view.findViewById<Button>(R.id.BTNsaveID).text = "Save changes"
val prgDatabase = PrgDatabase(context)
val value = prgDatabase.GrpsFind(holder.txtItemIDGrp.text.toString())
view.findViewById<EditText>(R.id.ETtitleID).setText(value.title)
view.findViewById<Button>(R.id.BTNsaveID).onClick {
if (view.findViewById<EditText>(R.id.ETtitleID).text.isNotEmpty()) {
val value = GrpsValues(
title = view.findViewById<EditText>(R.id.ETtitleID).text.toString(),
id = holder.txtItemIDGrp.text.toString(),
parent = holder.txtParentGrpIDGrp.text.toString()
)
prgDatabase.GrpsUpdate(
value
)
grpList[position] = value
dialog.dismiss()
this@RecAdapter.notifyDataSetChanged()
this@RecAdapter.notifyItemChanged(position)
}// if
} // btn on click
customView = view
}.show()
} // on click
} // if
} // GROUP
} // onBindViewHolder
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
if (groupsSize > 0) {
HOLDER = GROUP
return GrpsViewHolder(
LayoutInflater.from(parent.context).inflate(
R.layout.custom_rec_grps_layout,
parent,
false
)
)
} else {
HOLDER = ITEM
return ItemsViewHolder(
LayoutInflater.from(parent.context).inflate(
R.layout.custom_rec_items_layout,
parent,
false
)
)
}
}
inner class ItemsViewHolder(view: View) : RecyclerView.ViewHolder(view) {
val image: ImageView = view.findViewById(R.id.imageView)
val title: TextView = view.findViewById(R.id.TxtText)
val txtID: TextView = view.findViewById(R.id.TxtItemID)
val grpID: TextView = view.findViewById(R.id.TxtGrpID)
val txtDelete: TextView = view.findViewById(R.id.TxtDeleteID)
val txtEdit: TextView = view.findViewById(R.id.TxtEditID)
val layout: CardView = view.findViewById(R.id.ConstItemsID)
}
inner class GrpsViewHolder(view: View) : RecyclerView.ViewHolder(view) {
val titleGrp: TextView = view.findViewById(R.id.GrpTxtText)
val txtItemIDGrp: TextView = view.findViewById(R.id.GrpTxtItemID)
val txtParentGrpIDGrp: TextView = view.findViewById(R.id.GrpTxtGrpID)
val txtDeleteGrp: TextView = view.findViewById(R.id.GrpTxtDeleteID)
val txtEditGrp: TextView = view.findViewById(R.id.GrpTxtEditID)
val layoutGrp: CardView = view.findViewById(R.id.CnstGrpsID)
}
override fun getItemViewType(position: Int): Int {
return position
}
fun Mode() {
if (groupsSize > 0) {
groupsSize--
mode = GROUP
} else if (itemsSize > 0) {
itemsSize--
mode = ITEM
}
}
}
--------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: main
Process: artemis.team.picandtext, PID: 18621
java.lang.ClassCastException: GrpsViewHolder cannot be cast to RecAdapter$ItemsViewHolder
enter code here at RecAdapter.onBindViewHolder(RecAdapter.kt:66)
at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6781)
at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6823)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5752)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6019)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5858)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5854)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2230)
at androidx.recyclerview.widget.GridLayoutManager.layoutChunk(GridLayoutManager.java:557)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1517)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:612)
at androidx.recyclerview.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:171)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3924)
at androidx.recyclerview.widget.RecyclerView.onMeasure(RecyclerView.java:3336)
at android.view.View.measure(View.java:22071)
at androidx.constraintlayout.widget.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
at android.view.View.measure(View.java:22071)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6602)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:143)
at android.view.View.measure(View.java:22071)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6602)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1514)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:806)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:685)
at android.view.View.measure(View.java:22071)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6602)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at android.view.View.measure(View.java:22071)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6602)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1514)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:806)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:685)
at android.view.View.measure(View.java:22071)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6602)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at com.android.internal.policy.DecorView.onMeasure(DecorView.java:724)
at android.view.View.measure(View.java:22071)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2422)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1504)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1761)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1392)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6752)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:911)
at android.view.Choreographer.doCallbacks(Choreographer.java:723)
at android.view.Choreographer.doFrame(Choreographer.java:658)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:897)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime: at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
--------- beginning of system
最佳答案
您不能将一个ViewHolder类型的子类型强制转换为ViewHolder类的另一类型，因为它们不是同一类型。
ViewHolder
/\
RecHolder ItemsViewHolder
RecHolder是ViewHolder，而
ItemsViewHolder是Viewholder，但是仅仅因为它们共享同一个父对象并不能使
RecHolder成为
ItemsViewHolder，所以强制转换永远不会成功。
onCreateViewHolder返回的ViewHolder，因为这是进入
ViewHolder的
onBindViewHolder类型
if (viewHolder is RecHolder)或
if(viewHolder is ItemViewHolder)，以验证您是否在获取自己认为的内容。
关于android - ViewHolder不能强制转换为OtherViewHolder，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57578940/
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4
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