k-9/res/layout/foldable_linearlayout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:id="@+id/foldableControl"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:clickable="true"
        android:orientation="horizontal" >

        <ImageView
            android:id="@+id/foldableIcon"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:layout_marginRight="10dp"
            android:src="?attr/iconActionExpand" />

        <TextView
            android:id="@+id/foldableText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:text=""
            android:textColor="?android:attr/textColorTertiary" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/foldableContainer"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:visibility="invisible" />

</LinearLayout>