For those searching for a solution to the issue of the ripple effect not working on a programmatically created CardView (or in my case custom view which extends CardView) being shown in a RecyclerView, the following worked for me. Basically declaring the XML attributes mentioned in the other answers declaratively in the XML layout file doesn't seem to work for a programmatically created CardView, or one created from a custom layout (even if root view is CardView or merge element is used), so they have to be set programmatically like so:

private class MadeUpCardViewHolder extends RecyclerView.ViewHolder {
    private MadeUpCardView cardView;

    public MadeUpCardViewHolder(View v){
        super(v);

        this.cardView = (MadeUpCardView)v;

        // Declaring in XML Layout doesn't seem to work in RecyclerViews
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            int[] attrs = new int[]{R.attr.selectableItemBackground};
            TypedArray typedArray = context.obtainStyledAttributes(attrs);
            int selectableItemBackground = typedArray.getResourceId(0, 0);
            typedArray.recycle();

            this.cardView.setForeground(context.getDrawable(selectableItemBackground));
            this.cardView.setClickable(true);
        }
    }
}

MadeupCardView将CardView Kudos扩展到TypedArray部分的答案。

如果有一个根布局，比如RelativeLayout或LinearLayout，它包含了CardView中所有适配器项的组件，你必须在那个根布局中设置background属性。如:

<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="122dp"
android:layout_marginBottom="6dp"
android:layout_marginLeft="6dp"
android:layout_marginRight="6dp"
card_view:cardCornerRadius="4dp">

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/touch_bg"/>
</android.support.v7.widget.CardView>

如果你想在(child) Card视图中添加任何元素，你可以使用:

<ImageView
android:background="?android:attr/selectableItemBackground"

但如果你需要整个卡视图，这样做:

android:foreground="?android:attr/selectableItemBackground"
android:clickable="true"
android:focusable="true"

如果你用两种颜色，颜色会比其他颜色深。

然而，最简单的方法是

com.google.android.material.card.MaterialCardView

你应该在CardView中添加以下内容:

android:foreground="?android:attr/selectableItemBackground"
android:clickable="true"

在xml中添加以下内容:

android:clickable="true"
android:focusable="true"
android:background="?android:attr/selectableItemBackground"

并添加到适配器(如果是您的情况)

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            val attrs = intArrayOf(R.attr.selectableItemBackground)
            val typedArray = holder.itemView.context.obtainStyledAttributes(attrs)
            val selectableItemBackground = typedArray.getResourceId(0, 0)
            typedArray.recycle()

            holder.itemView.isClickable = true
            holder.itemView.isFocusable = true
            holder.itemView.foreground = holder.itemView.context.getDrawable(selectableItemBackground)
        }
    }

我对AppCompat并不满意，所以我编写了自己的CardView并反向移植了waves。这是在Galaxy S上运行的姜饼，所以这绝对是可能的。

要了解更多细节，请查看源代码。