CollapsingToolbarLayout a volte lascia uno spazio vuoto sotto

Question

Ho un problema. Qui ci sono le immagini di:

Ed ecco il codice:

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v4.widget.DrawerLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:id="@+id/drawerLayout" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

<android.support.design.widget.CoordinatorLayout 
    android:id="@+id/rootLayout" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

    <android.support.design.widget.AppBarLayout 
     android:layout_width="match_parent" 
     android:layout_height="256dp" 
     android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"> 

     <android.support.design.widget.CollapsingToolbarLayout 
      android:id="@+id/collapsingToolbarLayout" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      app:expandedTitleMarginStart="64dp" 
      app:layout_scrollFlags="scroll|exitUntilCollapsed"> 

      <android.support.v7.widget.Toolbar 
       android:id="@+id/toolbar" 
       android:layout_width="match_parent" 
       android:layout_height="?attr/actionBarSize" 
       android:background="?attr/colorPrimary" 
       android:minHeight="?attr/actionBarSize" 
       app:layout_collapseMode="pin" 
       app:popupTheme="@style/ThemeOverlay.AppCompat.Light" 
       app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" /> 

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

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

    <android.support.v4.widget.NestedScrollView 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:fillViewport="true" 
     app:layout_behavior="@string/appbar_scrolling_view_behavior"> 

     <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:orientation="vertical"> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 

      <Button 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:text="Yo Yo" /> 
     </LinearLayout> 

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

    <android.support.design.widget.FloatingActionButton 
     android:id="@+id/fabBtn2" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_gravity="bottom|right" 
     android:layout_marginBottom="@dimen/codelab_fab_margin_bottom" 
     android:layout_marginRight="@dimen/codelab_fab_margin_right" 
     app:borderWidth="0dp" 
     app:fabSize="normal" /> 

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

<android.support.design.widget.NavigationView 
    android:id="@+id/navigation" 
    android:layout_width="wrap_content" 
    android:layout_height="match_parent" 
    android:layout_gravity="start" 
    app:headerLayout="@layout/nav_header" 
    app:itemIconTint="@color/colorPrimaryDark" 
    app:itemTextColor="@color/colorPrimary" 
    app:menu="@menu/navigation_drawer_items" /> 

Si può vedere a volte, un bianco lo spazio appare sotto la barra degli strumenti, ma a volte no. Dou hai un'idea di cosa c'è che non va? Perché davvero non so come risolvere questo problema.

Grazie in anticipo,

Edit: posso solo riprodurre questo con Android 5.1.1 nel Nexus 7

Answer 1

Come suggerito in this answer, prova ad aggiungere:

android:layout_gravity="fill_vertical" 

a il NestedScrollView/RecyclerView.

Answer 2

Aggiungere android:fitsSystemWindows="true"-CoordinatorLayout, AppBarLayout e CollapsingToolbarLayout.

Answer 3

tenta di inserire questo attribuisce in NestedScrollView per forzare il comportamento corretto, questa è una soluzione e funziona per me:

android:paddingTop="0dp" 
    android:layout_marginTop="0dp"