CardView inserts dark line at bottom

Question

I'm using com.android.support:cardview-v7:23.3.0.

On API < 21 my CardView insists on placing a dark line at the bottom as shown here

This is my layout.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="wrap_content"
    android:gravity="center">

<android.support.v7.widget.CardView

    android:id="@+id/category_cardView"
    android:layout_width="320dp"
    android:layout_height="wrap_content"
    android:layout_margin="0dp"
    card_view:cardBackgroundColor="#80d0d0d0"
    card_view:cardCornerRadius="30dp"
    card_view:cardUseCompatPadding="true">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ImageView
            android:id="@+id/list_item_category_imageImageView"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_margin="3dp"
            tools:ignore="contentDescription"
            tools:src="@drawable/ic_launcher_find_the_fun" />

        <ImageButton
            android:id="@+id/list_item_category_listButton"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_alignParentRight="true"
            android:layout_centerVertical="true"
            android:layout_margin="3dp"
            android:background="@drawable/button_selector_category"
            android:contentDescription="@string/cd_list"
            android:padding="10dp"
            android:scaleType="fitXY"
            android:src="@drawable/ic_list_black_24dp" />

        <ImageButton
            android:id="@+id/list_item_category_mapButton"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_centerVertical="true"
            android:layout_toLeftOf="@+id/list_item_category_listButton"
            android:background="@drawable/button_selector_category"
            android:contentDescription="@string/cd_map"
            android:padding="10dp"
            android:scaleType="fitXY"
            android:src="@drawable/ic_map_black_24dp" />

        <!-- Title -->
        <TextView
            android:id="@+id/list_item_category_titleTextView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:layout_toLeftOf="@id/list_item_category_mapButton"
            android:layout_toRightOf="@id/list_item_category_imageImageView"
            android:paddingRight="3dp"
            android:textSize="17sp"
            android:textStyle="bold"
            android:typeface="sans"
            tools:text="Category Title" />
    </RelativeLayout>
</android.support.v7.widget.CardView>

I've tried various things to remove it. If I delete the line containing "card_view:cardCornerRadius="30dp"" here's what I see:

I see exactly the same as above if I explicitly set card_view:cardCornerRadius="0dp".

The following variations in my layout do not fix this (I've tried these mainly to debug, not because I really expected them to make a difference).

1. I changed to using card_view:cardUseCompatPadding="false"
2. card_view:cardUseCompatPadding="true"
3. card_view:cardPreventCornerOverlap="true"
4. card_view:cardPreventCornerOverlap="false"
5. card_view:contentPadding="0dp"

Can you suggest what is wrong with this layout or even a debugging step to try?

Answer 1

you forgot to add below attribute to your CardView and it works

XML

card_view:cardElevation="0dp"

OR

JAVA

cardView.setCardElevation(0);

cardView.setElevation() method and CardView attribute android:elevation will throw java.lang.NoSuchMethodError in platform before Android 5.0

Check

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="wrap_content"
    android:gravity="center">

    <android.support.v7.widget.CardView
        android:id="@+id/category_cardView"
        android:layout_width="320dp"
        android:layout_height="wrap_content"
        android:layout_margin="0dp"
        card_view:cardBackgroundColor="#80d0d0d0"
        card_view:cardCornerRadius="30dp"
        card_view:cardElevation="0dp"  //added
        card_view:cardUseCompatPadding="true">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <ImageView
                android:id="@+id/list_item_category_imageImageView"
                android:layout_width="50dp"
                android:layout_height="50dp"
                android:layout_margin="3dp"
                tools:ignore="contentDescription"
                tools:src="@drawable/ic_launcher_find_the_fun" />

            <ImageButton
                android:id="@+id/list_item_category_listButton"
                android:layout_width="50dp"
                android:layout_height="50dp"
                android:layout_alignParentRight="true"
                android:layout_centerVertical="true"
                android:layout_margin="3dp"
                android:background="@drawable/button_selector_category"
                android:contentDescription="@string/cd_list"
                android:padding="10dp"
                android:scaleType="fitXY"
                android:src="@drawable/ic_list_black_24dp" />

            <ImageButton
                android:id="@+id/list_item_category_mapButton"
                android:layout_width="50dp"
                android:layout_height="50dp"
                android:layout_centerVertical="true"
                android:layout_toLeftOf="@+id/list_item_category_listButton"
                android:background="@drawable/button_selector_category"
                android:contentDescription="@string/cd_map"
                android:padding="10dp"
                android:scaleType="fitXY"
                android:src="@drawable/ic_map_black_24dp" />

            <!-- Title -->
            <TextView
                android:id="@+id/list_item_category_titleTextView"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerVertical="true"
                android:layout_toLeftOf="@id/list_item_category_mapButton"
                android:layout_toRightOf="@id/list_item_category_imageImageView"
                android:paddingRight="3dp"
                android:textSize="17sp"
                android:textStyle="bold"
                android:typeface="sans"
                tools:text="Category Title" />
        </RelativeLayout>
    </android.support.v7.widget.CardView>
</LinearLayout>