仰角/陰影不適用於我的應用程序

我正在爲我們的頂尖項目創建一個android應用程序。我正在使用API 23.我在工具欄和其他組件上添加了高程，但陰影沒有出現。我的主題是否毀了它？仰角/陰影不適用於我的應用程序

<!-- Base application theme. --> 
    <style name="ThesisTheme" parent="Theme.AppCompat.Light.NoActionBar"> 
     <!-- Customize your theme here. --> 
     <item name="colorPrimary">@color/colorPrimary</item> 
     <item name="colorPrimaryDark">@color/colorPrimaryDark</item> 
     <item name="colorAccent">@color/colorAccent</item> 
     <item name="android:colorButtonNormal">@color/colorButton</item> 
     <item name="android:textColorPrimary">@color/textColorPrimary</item> 
     <item name="android:statusBarColor">@color/colorPrimaryDark</item> 
     <item name="android:navigationBarColor">@color/colorPrimary</item> 

     <item name="colorControlNormal">#c5c5c5</item> 
     <item name="colorControlActivated">@color/colorAccent</item> 
     <item name="colorControlHighlight">@color/colorPrimaryDark</item> 

     <item name="windowNoTitle">true</item> 
     <item name="windowActionBar">false</item> 
     <!--Datepicker--> 
     <item name="android:datePickerDialogTheme">@style/MyDatePickerDialogTheme</item> 

    </style>

當我嘗試包括工具欄，然後運行該程序，以我的手機/仿真器的陰影不會顯示。即使cardview

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:id="@+id/activity_login" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    tools:context="capstoreit.capstoreit.Login.Login" 
    android:background="@drawable/login_bg"> 


    <!--Layout for Login and Signup--> 
    <LinearLayout 
     android:orientation="vertical" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 

     android:layout_alignParentTop="true" 
     android:layout_alignParentStart="true"> 

     <android.support.design.widget.AppBarLayout 
      android:id="@+id/appbar" 
      android:layout_width="match_parent" 
      android:elevation="10dp" 
      android:layout_height="wrap_content"> 


    <!--Toolbar--> 
    <android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android" 
     xmlns:local="http://schemas.android.com/apk/res-auto" 
     android:id="@+id/login_toolbar" 
     android:layout_width="match_parent" 
     android:elevation="10dp" 
     local:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" 
     local:popupTheme="@style/ThemeOverlay.AppCompat.Light" 
     android:layout_height="?attr/actionBarSize" 
     android:background="@color/colorPrimary"> 

     <ImageView 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:src="@drawable/new_logo" 
      android:adjustViewBounds="true" 
      android:padding="5dp" 
      android:id="@+id/app_logo" /> 

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

    <!--Tab--> 
     <android.support.design.widget.TabLayout 
      android:id="@+id/tabs" 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      app:tabMode="fixed" 
      app:tabGravity="fill" 
      android:elevation="10dp" 
      android:background="@color/textColorPrimary" 
      app:tabSelectedTextColor="@color/colorAccent" 
      /> 
</android.support.design.widget.AppBarLayout> 


     <android.support.v4.view.ViewPager 
      android:id="@+id/viewpager" 
      android:layout_width="match_parent" 
      android:layout_height="0dp" 
      android:layout_weight="0.8" 
      app:layout_behavior="@string/appbar_scrolling_view_behavior" 
      android:layout_alignParentStart="true" 
      > 
     </android.support.v4.view.ViewPager> 

     <ImageView 
      android:layout_width="wrap_content" 
      android:layout_height="0dp" 
      android:layout_weight="0.2" 
      /> 



    </LinearLayout> 


</RelativeLayout>

截圖：海拔