Fixes crash on pre-Q devices.

Change-Id: I6501bab8f3e21b12ce9656ddbe8e4bf90f21166d

Author: nickbutcher

app/src/main/res/color/divider.xml

@@ -15,7 +15,6 @@
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
 
   <item
-      android:state_activated="true"
       android:alpha="0.20"
       android:color="?attr/colorOnSurface"/>
 

app/src/main/res/drawable/divider.xml

@@ -12,11 +12,8 @@
   or implied. See the License for the specific language governing permissions and limitations under
   the License.
   -->
-<inset
+<shape
     xmlns:android="http://schemas.android.com/apk/res/android"
-    android:inset="@dimen/grid_2">
-  <shape android:shape="rectangle">
-    <solid android:color="#979797"/>
-    <size android:height="1dp"/>
-  </shape>
-</inset>
+    android:shape="rectangle">
+  <solid android:color="@color/divider"/>
+</shape>

app/src/main/res/drawable/inset_divider.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright (c) 2019 Google Inc.
+
+  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+  in compliance with the License. You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software distributed under the License
+  is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+  or implied. See the License for the specific language governing permissions and limitations under
+  the License.
+  -->
+<inset
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:inset="@dimen/grid_2">
+  <shape android:shape="rectangle">
+    <solid android:color="@color/divider"/>
+    <size android:height="@dimen/divider_height"/>
+  </shape>
+</inset>

app/src/main/res/layout/fragment_learn.xml

@@ -135,7 +135,7 @@
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toBottomOf="@id/description"
             app:layout_constraintEnd_toEndOf="parent"
-            android:background="@drawable/divider"/>
+            android:background="@drawable/inset_divider"/>
 
         <TextView
             android:id="@+id/need"
@@ -276,7 +276,7 @@
           app:layout_constraintStart_toStartOf="parent"
           app:layout_constraintTop_toBottomOf="@id/playlist_title"
           app:layout_constraintEnd_toEndOf="parent"
-          android:background="@color/divider"
+          android:background="@drawable/divider"
           android:alpha="0"/>
 
       <androidx.recyclerview.widget.RecyclerView