安卓-kotlin -java.lang.ClassCastException

Question

RecyclerView多viewType錯誤

FATAL EXCEPTION: main 
     Process: com.example.expertsaraqeb.myapplication, PID: 4329 
     java.lang.ClassCastException: com.example.expertsaraqeb.myapplication.Madapter$MyHolder cannot be cast to com.example.expertsaraqeb.myapplication.MyViewH 
06-05 07:00:35.897 4329-4329/com.example.expertsaraqeb.myapplication E/AndroidRuntime: FATAL EXCEPTION: main 
    Process: com.example.expertsaraqeb.myapplication, PID: 4329 
    java.lang.ClassCastException: com.example.expertsaraqeb.myapplication.Madapter$MyHolder cannot be cast to com.example.expertsaraqeb.myapplication.MyViewH 
     at com.example.expertsaraqeb.myapplication.Madapter.onBindViewHolder(Madapter.kt:27) 
     at com.example.expertsaraqeb.myapplication.Madapter.onBindViewHolder(Madapter.kt:11) 
     at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6356) 
     at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6389) 
     at android.support.v7.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5335) 
     at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5598) 
     at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5440) 
     at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5436) 
     at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2224) 
     at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1551) 
     at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1511) 
     at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:595) 
     at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3583) 
     at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:3025) 
     at android.view.View.measure(View.java:16749) 
     at android.support.constraint.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:934) 
     at android.support.constraint.ConstraintLayout.onMeasure(ConstraintLayout.java:973) 
     at android.view.View.measure(View.java:16749) 
     at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1658) 
     at android.view.View.measure(View.java:16749) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5295) 
     at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:714) 
     at android.support.design.widget.HeaderScrollingViewBehavior.onMeasureChild(HeaderScrollingViewBehavior.java:90) 
     at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1391) 
     at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:784) 
     at android.view.View.measure(View.java:16749) 
     at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:1081) 
     at android.view.View.measure(View.java:16749) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5295) 
     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
     at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139) 
     at android.view.View.measure(View.java:16749) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5295) 
     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1413) 
     at android.widget.LinearLayout.measureVertical(LinearLayout.java:696) 
     at android.widget.LinearLayout.onMeasure(LinearLayout.java:589) 
     at android.view.View.measure(View.java:16749) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5295) 
     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
     at android.view.View.measure(View.java:16749) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5295) 
     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1413) 
     at android.widget.LinearLayout.measureVertical(LinearLayout.java:696) 
     at android.widget.LinearLayout.onMeasure(LinearLayout.java:589) 
     at android.view.View.measure(View.java:16749) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5295) 
     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
     at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2439) 
     at android.view.View.measure(View.java:16749) 
     at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2072) 
    at android. 

代碼：

package com.example.expertsaraqeb.myapplication 

import android.content.Context 
import android.support.v7.widget.RecyclerView 
import android.util.Log 
import android.view.LayoutInflater 
import android.view.View 
import android.view.ViewGroup 

class Madapter (val context: Context, val array:ArrayList<ModelItem>): RecyclerView.Adapter<Madapter.MyHolder>() { 
    var TYPE1=15 
    var TYPE2=28 
    override fun getItemViewType(position: Int): Int { 
     if (position==0){ 
      return TYPE1 
     }else{ 
      return TYPE2 
     } 
    } 
    override fun getItemCount(): Int { 
     return array.size 
    } 

    override fun onBindViewHolder(p0: MyHolder?, p1: Int) { 
     if (p0!!.itemViewType==TYPE1){ 
      val my= p0 as MyViewH //Error here 

      Log.d("walidalhasn","p"+getItemViewType(p1)) 

     }else if (p0.itemViewType==TYPE1){ 
      Log.d("walidalhasn","j"+getItemViewType(p1)) 


     } 
    } 

    override fun onCreateViewHolder(p0: ViewGroup?, p1: Int): MyHolder { 
     if (getItemViewType(p1)==TYPE1){ 
      val view= LayoutInflater.from(context).inflate(R.layout.row_no_color,p0,false) 
      return MyViewH(view) 
     }else { 
      val view= LayoutInflater.from(context).inflate(R.layout.home_row,p0,false) 
      return MyHolder(view) 

     } 

    } 

    open class MyHolder (view: View):RecyclerView.ViewHolder(view) 


} 

class MyViewH(view: View?) : Madapter.MyHolder(view!!) 

Answer 1

在onCreateViewHolder(p0: ViewGroup?, p1: Int)，p1代表viewType。

應該

if (p1 == TYPE1) { 

，而不是

if (getItemViewType(p1) == TYPE1) { 

此外，你可能想從getItemCount返回array.size + 1，因爲你將頭視圖。