NestedScrollView and CoordinatorLayout. Issue on Scrolling

Question

I have a strange issue with the CoordinatorLayout and the NestedScrollView (with the design support library 22.2.0)

Using a content smaller than NestedScrollView I should have a fixed content. However trying to scroll up and down the content I can obtain that the content is displaced and never again in their own place.

Here a little sample:

Here the code:

<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/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:layout_scrollFlags="scroll|enterAlways" />

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

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

        <FrameLayout
            android:paddingTop="24dp"
            android:id="@+id/fragment_container"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:padding="@dimen/padding">

        </FrameLayout>

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

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab_action"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="end|bottom"
        android:layout_margin="16dp"
        android:visibility="gone"
        android:src="@drawable/ic_done" />

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

Answer 1

This can also be observed in the cheesesquare demo when removing all but one card in the details fragment.

I was able to solve this (for now) using this class: https://gist.github.com/EmmanuelVinas/c598292f43713c75d18e

<android.support.v4.widget.NestedScrollView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="com.evs.demo.layout.FixedScrollingViewBehavior">
    .....   
</android.support.v4.widget.NestedScrollView>

Answer 2

I think that it is not a bug in the support lib,just use this

<android.support.v4.widget.NestedScrollView
    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:fillViewport="true"
    android:layout_gravity="fill_vertical"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

Answer 3

android:layout_gravity="fill_vertical" worked for me too.

Answer 4

I might be late with my answer but here goes. I was having a similar problem, but none of the above mentioned solutions worked for me. In the end I fixed it by using version 23 of the support library.

...
compileSdkVersion 23
...
targetSdkVersion 23
...
compile 'com.android.support:appcompat-v7:23.1.0'
compile 'com.android.support:support-v4:23.1.0'
compile 'com.android.support:design:23.1.0'

Answer 5

The onMeasureChild() method is called many times during the layout process. Apparently, the key is getting a non-zero value for the child height early in the process. ScrollingViewBehavior fails to do so in the following:

int scrollRange = appBar.getTotalScrollRange();
int height = parent.getHeight() 
             - appBar.getMeasuredHeight()
             + scrollRange;

FixedScrollingviewBehavior fixes this with:

int height = parent.getHeight() 
             - appBar.getMeasuredHeight() 
             + Math.min(scrollRange, parent.getHeight() - heightUsed);

which very early gives height the value of -128, the height of the app bar.

An alternative, close to the original is:

int height = parent.getMeasuredHeight()
             - appBar.getMeasuredHeight()
             + scrollRange;