CollapsingToolbarLayout pushes NestedScrollView down in android

Question

I encountered a problem on first launch of a fragment. It seems like CoordinatorLayout adds a negative margin to NestedScrollView which is equal to CollapsingToolbarLayout's height in collapsed state (I tested it by changing the height's value). As a result RecyclerView which lives in the NestedScrollView cannot scroll up to show few of its bottom items.

There are some similar questions on SO (like this, this and this), but they don't provide a solution that worked for me, and moreover, they don't give any explanations of what can cause the issue.

One interesting note is that if I rotate, or turn the screen off and on it would rebuild the layout and afterwords it will show up correctly. Also, if I click on an item it will trigger something so then I would be able to scroll those hidden items. As a workaround it would be nice to call a function that rebuilds the layout correctly manually but I failed to figure out what it was (see what I tried to do below)

What I tried to do:

• adding bottom margin equal to toolbar's height to NestedScrollView. Although it helped on first launch but after I clicked on an item or rotate the screen the extra margin would push the view up from the bottom of the screen.

• I couldn't find any problem in my code while debugging.

• calling getView.invalidate() didn't help as well.

Can somebody help me to figure out what can cause the issue, please?

fragment_player.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="ru.orgin.glagol.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay"
        android:stateListAnimator="@animator/appbar_always_elevated">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/toolbar_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            app:titleEnabled="false">

            <include layout="@layout/player_view"/>

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="@dimen/player_toolbar_height"
                app:layout_collapseMode="none"
                app:popupTheme="@style/AppTheme.PopupOverlay" />

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

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

    <android.support.v4.widget.NestedScrollView
        android:id="@+id/scrollView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" >

        <ViewAnimator
            android:id="@+id/viewAnimator"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:inAnimation="@android:anim/fade_in"
            android:outAnimation="@android:anim/fade_out">

            <ProgressBar
                android:layout_width="wrap_content"
                android:layout_height="64dp"
                android:layout_gravity="center"
                style="?android:attr/progressBarStyle"/>

            <android.support.v7.widget.RecyclerView
                android:id="@+id/recyclerView"
                android:nestedScrollingEnabled="false"
                android:layout_width="match_parent"
                android:layout_height="match_parent"/>

            <TextView
                android:layout_width="match_parent"
                android:layout_height="64dp"
                android:gravity="center"
                android:layout_gravity="center"
                android:text="@string/empty_history_books" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="64dp"
                android:gravity="center"
                android:layout_gravity="center"
                android:text="@string/error_loading_data" />

        </ViewAnimator>

    </android.support.v4.widget.NestedScrollView>

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

Update: Still don't know the reason but it seems like adding minHeight attribute to CollapsingToolbarLayout does the trick.

Answer 1

Adding minHeight attribute prevents CollapsingToolbarLayout from unexpected behavior:

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay"
    android:stateListAnimator="@animator/appbar_always_elevated">

    <android.support.design.widget.CollapsingToolbarLayout
        android:id="@+id/toolbarLayout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        android:minHeight="@dimen/player_toolbar_height"
        app:layout_scrollFlags="scroll|exitUntilCollapsed"
        app:titleEnabled="false">

        <include layout="@layout/player_view"/>

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="@dimen/player_toolbar_height"
            app:layout_collapseMode="none"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

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

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