How to remove default cardview border from the layout.xml

Question

I can't remove the default border of a CardView. Has anyone encountered this problem before?

Two border lines are overlapping

CardviewDesign.xml

<android.support.v7.widget.CardView
    xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:android2="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:card_view="https://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/card_view"
    android:layout_width="match_parent"

    android2:layout_marginTop="5dp"
    android2:layout_marginLeft="5dp"
    android2:layout_marginRight="5dp"
    android2:layout_gravity="center|top"

    card_view:cardCornerRadius="20dp"
    android2:layout_width="match_parent"
    android2:layout_height="wrap_content">

<FrameLayout
    android2:layout_width="match_parent"
    android2:layout_height="400dp"

    android2:background="@drawable/cardviewstring">



    <LinearLayout
        android2:orientation="vertical"
        android2:layout_width="380dp"
        android2:layout_height="match_parent"


        android2:weightSum="1"
        android2:layout_marginRight="20dp">

        <LinearLayout
            android2:orientation="vertical"
            android2:layout_width="match_parent"
            android2:layout_weight="1"
            android2:layout_height="250dp">

            <ImageView
                android2:layout_width="match_parent"
                android2:layout_height="match_parent"
                app:srcCompat="@mipmap/ic_launcher"
                android2:id="@+id/imageView4" />

        </LinearLayout>

        <LinearLayout
            android2:orientation="vertical"
            android2:layout_width="match_parent"
            android2:layout_height="wrap_content"
            android2:paddingTop="25dp">

            <ScrollView
                android2:layout_width="match_parent"
                android2:layout_height="84dp"
                android2:background="@drawable/screen_background_dark_transparent"
                android2:layout_marginLeft="3dp">

                <LinearLayout
                    android2:layout_width="match_parent"
                    android2:layout_height="wrap_content"
                    android2:orientation="vertical" >

                    <TextView
                        android2:text="TextView"
                        android2:layout_width="match_parent"
                        android2:layout_height="wrap_content"
                        android2:id="@+id/textView4" />

                    <TextView
                        android2:text="TextView"
                        android2:layout_width="match_parent"
                        android2:layout_height="35dp"
                        android2:id="@+id/textView3" />
                </LinearLayout>
            </ScrollView>

        </LinearLayout>

        <LinearLayout
            android2:orientation="vertical"
            android2:layout_marginTop="10dp"
            android2:layout_width="match_parent"
            android2:layout_height="42dp"
            android:layout_alignParentBottom="true">

            <LinearLayout
                android2:orientation="horizontal"
                android2:layout_width="match_parent"
                android2:layout_height="match_parent">

                <ImageView
                    android2:layout_width="wrap_content"
                    android2:layout_height="wrap_content"
                    app:srcCompat="@drawable/ic_share"
                    android2:id="@+id/imageView3"
                    android2:layout_weight="1" />

                <ImageView
                    android2:layout_width="wrap_content"
                    android2:layout_height="wrap_content"
                    app:srcCompat="@drawable/ic_like"
                    android2:id="@+id/imageView2"
                    android2:layout_weight="1" />
            </LinearLayout>
        </LinearLayout>
    </LinearLayout>

</FrameLayout>

drawable/cardviewstring.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle" >
    <solid android:color="#ffffffff" />
    <stroke android:width="3dip" android:color="#000000"/>
    <corners android:radius="20dip"/>
</shape>

color.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#154360</color>
    <color name="colorPrimaryDark">#154360</color>
    <color name="colorAccent">#ffffff</color>
    <color name="colorButton">#A0FFFFFF</color>
    <color name="colorView">#A0FF4081</color>
    <color name="white">#ffff</color>
    <color name="lightblue">#ADD8E6</color>
    <color name="tabsScrollColor">#ADD8E6</color>
    <color name="gray">#C0C0C0</color>
    <color name="black">#000000</color>

    <color name="ccolorPrimary">#3F51B5</color>
    <color name="ccolorPrimaryDark">#303F9F</color>
    <color name="ccolorAccent">#FF4081</color>
    <color name="year">#999999</color>
    <color name="title">#222222</color>

    <drawable name="screen_background_dark_transparent">#80000000</drawable>

</resources>

Answer 1

Set app:cardElevation="0dp" for CardView widget.