android - CardView 阴影不显示，如果不止一张卡片相互重叠

Question

下面是引用/输出截图

在屏幕截图中，您可以看到有四个重叠的 CardView，但顶部和右侧的角阴影没有显示在前面的卡片上，(仅显示最后一张卡片的阴影)

更新:下面 Lollipop 影子正在工作

下面是一个 CardView 的 XML 代码，我以编程方式膨胀这些 CardView 布局，并设置 XY 属性以实现重叠 View

<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="@dimen/offer_card_width"
    android:layout_height="97dp"
    app:cardBackgroundColor="@color/windowBackgroundSecondary"
    app:cardPreventCornerOverlap="false"
    app:cardUseCompatPadding="true">

    <RelativeLayout
        android:padding="@dimen/padding_regular"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:id="@+id/icon_offer"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:background="@drawable/bg_circular_offer"
            android:padding="8dp"
            android:src="@drawable/ic_content_copy" />

        <TextView
            android:layout_marginLeft="@dimen/margin_regular"
            android:id="@+id/text_offer_title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_toRightOf="@+id/icon_offer"
            android:ellipsize="end"
            android:maxLines="1"
            android:textColor="@color/submit_button"
            android:textSize="@dimen/text_size_regular"
            android:text="Some content will be there" />

        <TextView
            android:id="@+id/text_offer_desc"
            android:layout_marginTop="@dimen/margin_medium"
            android:layout_marginLeft="@dimen/margin_regular"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/text_offer_title"
            android:layout_toRightOf="@+id/icon_offer"
            android:ellipsize="end"
            android:maxLines="1"
            android:textColor="@color/black"
            android:textSize="@dimen/text_size_small"
            android:text="Some content will be there, Some content will be there" />

        <LinearLayout
            android:layout_marginLeft="@dimen/margin_regular"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_toRightOf="@+id/icon_offer"
            android:orientation="horizontal">

            <TextView
                android:textColor="#6f6f6f"
                android:textSize="@dimen/text_size_regular"
                android:layout_gravity="center_vertical"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Code:" />

            <TextView
                android:id="@+id/text_copy_code"
                android:layout_marginLeft="@dimen/margin_medium"
                android:layout_gravity="center_vertical"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:drawablePadding="@dimen/padding_medium"
                android:ellipsize="end"
                android:maxLines="1"
                android:drawableRight="@drawable/ic_content_copy"
                android:textColor="@color/label_header_opac"
                android:textSize="@dimen/text_size_regular"
                android:text="TEST2016" />
        </LinearLayout>

    </RelativeLayout>

</android.support.v7.widget.CardView>

下面是用于扩充 cardview 布局的 java 代码

private void setupUi() {

        CardView cardView;
        LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        frameLayout = (FrameLayout) findViewById(R.id.container_pager_offer);
        frameLayout.removeAllViews();

        CardView.LayoutParams params; 

        int cardMargin = (int) getResources().getDimension(R.dimen.offer_card_overlapping);
        int sideMargin = (int) getResources().getDimension(R.dimen.margin_semi_large);

        for (int i = 0; i < 4; i++) {
            cardView = (CardView) inflater.inflate(R.layout.card_offer_for_pager, null);
            TextView textView = (TextView) cardView.findViewById(R.id.text_copy_code);
            CommonUtils.setIconColor(textView, 2, R.color.label_header_opac);
            params = new CardView.LayoutParams((int) getResources().getDimension(R.dimen.offer_card_width),
                    (int) getResources().getDimension(R.dimen.offer_card_height));
            cardView.setX(cardMargin * ( 4 - i ) + sideMargin); //XCOORD
            cardView.setY(cardMargin * ( i + 1 )); //YCOORD
            cardView.setLayoutParams(params);
                        frameLayout.addView(cardView);
        }
}

Answer 1

我已经找到了一个简单的答案，

请为 CardView 添加一个父布局，这个父布局可以是 LinearLayout 或 RelativeLayout，并为父布局提供透明背景，这样就可以了

下面是例子

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.v7.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:cardBackgroundColor="@color/mdtp_circle_color"
        app:cardPreventCornerOverlap="false"
        app:cardUseCompatPadding="true">
    </android.support.v7.widget.CardView>
</LinearLayout >