使用 background_selector 不会更改 RecyclerView 视图

Question

我正在尝试在选择项目时切换项目背景颜色。

我可以看到它的逻辑是有效的，但背景不会改变。日志打印显示选择确实有效，但背景无效。

来自 background_selector:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@android:color/holo_green_light" android:state_pressed="false" android:state_selected="true" />
    <item android:drawable="@android:color/holo_purple" android:state_selected="false" />
</selector>

来自 task_row.xml:

<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    app:cardCornerRadius="3dp"
    app:cardElevation="3dp"
    android:id="@+id/tasksCardView"
    android:background="@drawable/background_selector"
    app:cardUseCompatPadding="true">

来自适配器代码：


class MyTasksAdapter (
    val arrayList: ArrayList<Task>,
   
    val selectedItemsList: ArrayList<Task>,
    val deletedItemsList: ArrayList<String>) :
    RecyclerView.Adapter<MyTasksAdapter.ViewHolder>() {

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView), View.OnClickListener {

        private var cardView: CardView = itemView.tasksCardView

        private val selectedItems = SparseBooleanArray()
        override fun onClick(view: View) {
            if (selectedItems[adapterPosition, false]) {
                selectedItems.delete(adapterPosition)
                cardView.isSelected = false
                Log.d("Item selected AA", "position: $position")
            }
            else {
                selectedItems.put(adapterPosition, true)
                view.isSelected = true
                Log.d("Item selected BB", "position: $position")
            }
        }

        init {
            itemView.setOnClickListener(this)

        }

也尝试过将 cardview 更改为 view，但也无济于事。


class MyTasksAdapter (
    val arrayList: ArrayList<Task>,
    val selectedItemsList: ArrayList<Task>,
    val deletedItemsList: ArrayList<String>) :
    RecyclerView.Adapter<MyTasksAdapter.ViewHolder>() {

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView), View.OnClickListener {

        //private lateinit var item: ClipData.Item
        private var cardView: CardView = itemView.tasksCardView

        private val selectedItems = SparseBooleanArray()
        override fun onClick(view: View) {
            if (selectedItems[adapterPosition, false]) {
                selectedItems.delete(adapterPosition)
                view.isSelected = false
                Log.d("Item selected AA", "position: $position")
            }
            else {
                selectedItems.put(adapterPosition, true)
                view.isSelected = true
                Log.d("Item selected BB", "position: $position")
            }
        }

        init {
            itemView.setOnClickListener(this)

        }

感谢您的帮助。

Answer 1

现在工作。将其移动到 relative_layout header: 而不是 cardview_layout header

<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    app:cardCornerRadius="3dp"
    app:cardElevation="3dp"
    android:id="@+id/tasksCardView"
    android:hapticFeedbackEnabled="true"
    app:cardUseCompatPadding="true">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        **android:background="@drawable/background_selector"**
        android:padding="16dp">

使用 background_selector 不会更改 RecyclerView 视图

RecyclerView view doesn't change using background_selector

background

android-recyclerview