View can not be anchored to the parent CoordinatorLayout

Question

I just updated to appcompat library from 23.1.1 to 23.2 and now application stopped working on java.lang.IllegalStateException: View can not be anchored to the the parent CoordinatorLayout.

java.lang.IllegalStateException: View can not be anchored to the the parent CoordinatorLayout

Crash comes from resolveAnchorView method of CoordinatorLayout when parent (CoordinatorLayout is not in edit mode). Layout is used as root element in base activity and contains different layouts (toolbar, progressbar and finally relativelayout with inflated layout of activity.

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/base_activity__main_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/shared__color_primary">

    <ProgressBar
        android:id="@+id/base_activity__progress_bar_top"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:indeterminate="true"
        android:visibility="gone" />

    <ViewSwitcher
        android:id="@+id/base_activity__switcher"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/base_activity__progress_bar_top">

        <LinearLayout
            android:id="@+id/base_activity__progress_bar_layout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:gravity="center"
            android:orientation="vertical">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/_loading"
                android:textStyle="italic" />

            <ProgressBar
                android:id="@+id/base_activity__progress_bar"
                style="?android:attr/progressBarStyleHorizontal"
                android:layout_width="150dp"
                android:layout_height="wrap_content"
                android:indeterminate="true" />
        </LinearLayout>

        <RelativeLayout
            android:id="@+id/base_activity__main_content_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

    </ViewSwitcher>

    <RelativeLayout
        android:id="@+id/base_activity__add_button__container"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@android:color/transparent" />

</android.support.design.widget.CoordinatorLayout>

Answer 1

You cannot set the layout anchor attribute to the co ordinator layout itself app:layout_anchor="@id/base_activity__main_layout", this is wrong, you need to set some direct child of the co ordinator as this layouts anchor