I have 2 cards in a single RelativeLayout.
The problem is that there is no elevation or shadow underneath the second card.
See the screenshot here: screenshot
Here's what I have done in the xml file:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorPrimary"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.abc.xyz.abcActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="@+id/cba_screen_text"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:text="@string/cba_screen_text"
android:textColor="@android:color/white"
android:textSize="@dimen/cba_screen_text"
android:gravity="center_horizontal|center_vertical"
android:layout_gravity="center_horizontal|center_vertical"/>
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/signup_screen_first_cardview_top_margin"
app:contentPadding="10dp"
app:cardBackgroundColor="@android:color/white">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal|center_vertical"
android:orientation="vertical">
<!-- N Label -->
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="@dimen/abc_screen_name_label_topmargin">
<EditText android:id="@+id/input_n"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textCapWords"
android:textColor="@color/colorPrimary"
android:hint="N" />
</android.support.design.widget.TextInputLayout>
<!-- E Label -->
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/abc_screen_name_label_topmargin"
android:layout_marginBottom="@dimen/abc_screen_name_label_topmargin">
<EditText android:id="@+id/input_e"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textCapWords"
android:textColor="@color/colorPrimary"
android:hint="E" />
</android.support.design.widget.TextInputLayout>
<!-- P Label -->
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/abc_screen_name_label_topmargin"
android:layout_marginBottom="@dimen/abc_screen_name_label_topmargin">
<EditText android:id="@+id/input_p"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textCapWords"
android:textColor="@color/colorPrimary"
android:hint="P"/>
</android.support.design.widget.TextInputLayout>
<!-- S Button -->
<android.support.v7.widget.AppCompatButton
android:id="@+id/btn_s"
android:layout_width="@dimen/s_btn_width"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/c_btn_topmargin"
android:layout_gravity="center_horizontal"
android:padding="12dp"
android:text="C"
android:textSize="@dimen/s_btn_text_size"/>
<TextView android:id="@+id/l"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/a_topmargin"
android:text="A"
android:gravity="center"
android:textSize="16sp"/>
</LinearLayout>
</android.support.v7.widget.CardView>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="5dp"
android:layout_gravity="center_horizontal|center_vertical"
android:text="OR"
android:textStyle="bold"
android:textSize="20sp"
android:textColor="@android:color/white"/>
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:contentPadding="10dp"
app:cardElevation="2dp"
app:cardBackgroundColor="@android:color/white">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<com.google.android.gms.common.SignInButton
android:id="@+id/google_login_button"
android:layout_width="@dimen/sign_in_btn_width"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal" />
<com.facebook.login.widget.LoginButton
android:id="@+id/facebook_login_button"
android:layout_width="@dimen/sign_in_btn_width"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:layout_gravity="center_horizontal" />
</LinearLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
</RelativeLayout>
Please let me know why is this happening and how can I have the shadow/elevation underneath the second card too?
Your LinearLayout is wrapping its height, cutting off the shadow of the card at the bottom.
Either put some padding on the bottom of the LinearLayout or set it to match_parent on its height.
PS that outer RelativeLayout is useless -- get rid of it and put all the padding and background on the inner LinearLayout
来源：https://stackoverflow.com/questions/36393540/no-shadow-elevation-underneath-second-card-if-there-are-two-card-in-the-layout