android - Kotlin Android 工作室充气机崩溃问题

Question

所以我正在做一个项目，我现在在使用 recyclerview 和 cardview 时遇到了很大的麻烦，我没有从代码中得到任何错误，但它一直在崩溃，我不知道为什么

**class MyAdapter(private val myDataset: ArrayList<Results>) :**
RecyclerView.Adapter<MyAdapter.MyViewHolder>() {

class MyViewHolder(val cardView: CardView) : RecyclerView.ViewHolder(cardView) {
    val userName = itemView.findViewById<TextView>(R.id.name)
}

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyAdapter.MyViewHolder {
  **val aCardView = LayoutInflater.from(parent.context).inflate(R.layout.card_view, parent, false) as CardView**
    return MyViewHolder(aCardView)
}

override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
    holder.userName.text = myDataset[position].userName

}

override fun getItemCount() = myDataset.size
}

Logcat 只指向 ** 行，但实际上什么都没有，有什么想法吗？对不起，花了这么长时间，我对我能发布和不能发布的内容很挑剔，我希望这能提供更多细节。

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">

<androidx.cardview.widget.CardView
android:id="@+id/card"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">

<LinearLayout
    android:id="@+id/linearLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

  <TextView
                android:id="@+id/name"
                android:layout_width="125dp"
                android:layout_height="wrap_content"
                android:layout_marginTop="8dp"
                android:layout_marginEnd="172dp"
                android:layout_marginRight="172dp"
                android:layout_marginBottom="74dp"
                android:text="This will be the name"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <TextView
                android:id="@+id/description"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="4dp"
                android:layout_marginEnd="240dp"
                android:layout_marginRight="240dp"
                android:layout_marginBottom="50dp"
                android:text="TextView"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintTop_toBottomOf="@+id/name" />


        </androidx.constraintlayout.widget.ConstraintLayout>

    </LinearLayout>
  </androidx.cardview.widget.CardView>

  </androidx.constraintlayout.widget.ConstraintLayout>

标签： androidkotlinandroid-recyclerviewandroid-cardview

Answer 1

2020-03-16 14:47:11.159 26375-26375/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.githubmobile, PID: 26375
java.lang.ClassCastException: androidx.constraintlayout.widget.ConstraintLayout cannot be cast to androidx.cardview.widget.CardView
    at com.example.githubmobile.MyAdapter.onCreateViewHolder(MyAdapter.kt:19)
    at com.example.githubmobile.MyAdapter.onCreateViewHolder(MyAdapter.kt:10)
    at androidx.recyclerview.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:7078)
    at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6235)
    at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6118)
    at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6114)
    at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2303)
    at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1627)
    at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
    at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
    at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4134)
    at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3851)
    at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4404)
    at android.view.View.layout(View.java:21927)
    at android.view.ViewGroup.layout(ViewGroup.java:6260)
    at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1915)
    at android.view.View.layout(View.java:21927)
    at android.view.ViewGroup.layout(ViewGroup.java:6260)
    at com.google.android.material.appbar.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:148)
    at com.google.android.material.appbar.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:43)
    at com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior.onLayoutChild(AppBarLayout.java:1892)
    at androidx.coordinatorlayout.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:918)
    at android.view.View.layout(View.java:21927)
    at android.view.ViewGroup.layout(ViewGroup.java:6260)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
    at android.view.View.layout(View.java:21927)
    at android.view.ViewGroup.layout(ViewGroup.java:6260)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
    at android.view.View.layout(View.java:21927)
    at android.view.ViewGroup.layout(ViewGroup.java:6260)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
    at android.view.View.layout(View.java:21927)
    at android.view.ViewGroup.layout(ViewGroup.java:6260)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
    at android.view.View.layout(View.java:21927)
    at android.view.ViewGroup.layout(ViewGroup.java:6260)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
    at com.android.internal.policy.DecorView.onLayout(DecorView.java:779)
    at android.view.View.layout(View.java:21927)
    at android.view.ViewGroup.layout(ViewGroup.java:6260)
    at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3080)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2590)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1721)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7598)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:966)
    at android.view.Choreographer.doCallbacks(Choreographer.java:790)
2020-03-16 14:47:11.160 26375-26375/? E/AndroidRuntime:     at android.view.Choreographer.doFrame(Choreographer.java:725)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:951)
    at android.os.Handler.handleCallback(Handler.java:883)
    at android.os.Handler.dispatchMessage(Handler.java:100)
    at android.os.Looper.loop(Looper.java:214)
    at android.app.ActivityThread.main(ActivityThread.java:7356)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)