无法平滑地使用NestedScrollView滚动AppBarLayout和折叠式工具栏

Question

我正在开发一个安卓应用程序，我使用了CoordinatorLayout、AppBarLayout和CollapsingToolbarLayout来实现折叠式工具栏功能。

我在布局中使用NestedScrollView来展开和折叠同一布局中的AppBarLayout。当我尝试从屏幕中心向上滚动时，它不起作用，但当我尝试从屏幕右上角向上滚动时，则可以平稳滚动。

下面是我的xml文件：

layout.xml

<android.support.v4.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:fillViewport="true"
    android:fitsSystemWindows="true"
    android:paddingBottom="2dp"
    android:paddingLeft="5dp"
    android:paddingRight="5dp"
    android:paddingTop="5dp"
    android:layout_gravity="fill_vertical"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@color/fragment_back_color"
            android:orientation="vertical">


            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:padding="5dp">

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center"
                    android:background="@drawable/new_recharge" />

                <com.spiceladdoo.views.RobotTextviewRegular
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center"
                    android:layout_marginLeft="10dp"
                    android:text="NEW PAYMENT"
                    android:textColor="@color/offer_name_text_color" />

            </LinearLayout>


            <RelativeLayout

                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="5dp"
                android:layout_marginRight="5dp"
                android:background="@color/white"
                android:paddingBottom="20dp"
                android:paddingLeft="10dp"
                android:paddingRight="10dp"
                android:paddingTop="20dp">

                <HorizontalScrollView
                    android:id="@+id/hsv"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content"
                    android:layout_alignParentTop="true"
                    android:fillViewport="true"
                    android:measureAllChildren="false"
                    android:scrollbars="none">

                    <LinearLayout
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_centerInParent="true"
                        android:orientation="horizontal">

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

                            <ImageView
                                android:id="@+id/wallet_recharge"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:background="@drawable/wallet_recherge" />

                            <com.spiceladdoo.views.RobotTextviewRegular
                                android:layout_width="65dp"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:layout_marginTop="5dp"
                                android:gravity="center"
                                android:text="WALLET"
                                android:textColor="@color/offer_name_text_color"
                                android:textSize="12sp" />
                            >

                        </LinearLayout>

                        <View
                            android:layout_width="5dp"
                            android:layout_height="20dp"

                            android:background="@color/white" />

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

                            <ImageView
                                android:id="@+id/prepaid_recharge"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:background="@drawable/prepaid_recherge" />

                            <com.spiceladdoo.views.RobotTextviewRegular
                                android:layout_width="65dp"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:layout_marginTop="5dp"
                                android:gravity="center"
                                android:text="PREPAID"
                                android:textColor="@color/offer_name_text_color"
                                android:textSize="12sp" />
                            >

                        </LinearLayout>

                        <View
                            android:layout_width="5dp"
                            android:layout_height="20dp"

                            android:background="@color/white" />

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

                            <ImageView
                                android:id="@+id/postpaid_recharge"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:background="@drawable/postpaid_recherge" />

                            <com.spiceladdoo.views.RobotTextviewRegular
                                android:layout_width="65dp"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:layout_marginTop="5dp"
                                android:gravity="center"
                                android:text="POSTPAID"
                                android:textColor="@color/offer_name_text_color"
                                android:textSize="12sp" />
                            >

                        </LinearLayout>

                        <View
                            android:layout_width="5dp"
                            android:layout_height="20dp"
                            android:background="@color/white" />

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

                            <ImageView
                                android:id="@+id/dth_recharge"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:background="@drawable/dth_recherge" />

                            <com.spiceladdoo.views.RobotTextviewRegular
                                android:layout_width="65dp"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:layout_marginTop="5dp"
                                android:gravity="center"
                                android:text="DTH"
                                android:textColor="@color/offer_name_text_color"
                                android:textSize="12sp" />
                            >

                        </LinearLayout>

                        <View
                            android:layout_width="5dp"
                            android:layout_height="20dp"
                            android:background="@color/white" />

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

                            <ImageView
                                android:id="@+id/landline_recharge"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:background="@drawable/landline_recherge" />

                            <com.spiceladdoo.views.RobotTextviewRegular
                                android:layout_width="65dp"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:layout_marginTop="5dp"
                                android:gravity="center"
                                android:text="LANDLINE"
                                android:textColor="@color/offer_name_text_color"
                                android:textSize="12sp" />
                            >

                        </LinearLayout>

                        <View
                            android:layout_width="5dp"
                            android:layout_height="20dp"
                            android:background="@color/white" />

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

                            <ImageView
                                android:id="@+id/datacard_recharge"
                                android:layout_width="wrap_content"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:background="@drawable/datacard_recherge" />

                            <com.spiceladdoo.views.RobotTextviewRegular
                                android:layout_width="65dp"
                                android:layout_height="wrap_content"
                                android:layout_gravity="center"
                                android:layout_marginTop="5dp"
                                android:gravity="center"
                                android:text="DATACARD"
                                android:textColor="@color/offer_name_text_color"
                                android:textSize="12sp" />
                            >

                        </LinearLayout>
                    </LinearLayout>
                </HorizontalScrollView>
            </RelativeLayout>


            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal"

                android:paddingBottom="10dp"
                android:paddingLeft="5dp"
                android:paddingRight="5dp"
                android:paddingTop="10dp">

                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center"
                    android:background="@drawable/recent" />

                <com.spiceladdoo.views.RobotTextviewRegular
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center"
                    android:layout_marginLeft="10dp"
                    android:text="RECENT"
                    android:textColor="@color/offer_name_text_color" />

            </LinearLayout>

            <ListView
                android:id="@+id/recent_recharge_list"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_marginLeft="5dp"
                android:layout_marginRight="5dp">

            </ListView>


        </LinearLayout>

        <FrameLayout xmlns:tools="http://schemas.android.com/tools"
            android:id="@+id/recharge_container"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:visibility="visible"
            tools:ignore="MergeRootFrame">

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

我希望从屏幕中央向上滚动时，能像从移动设备右下角向上滚动一样平稳。请观看下面提到的视频，以更清晰地了解问题。

https://www.dropbox.com/s/gscfc8vfc7kkpxp/device-2015-12-30-160119.mp4?dl=0

- Kushminder Garg

Answer 1

我相信，我已经成功了：

你可以在这里找到源代码 - 随意尝试;

我以Google\designlibdemo为例。

这是我的Activity的样子:

<?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/drawer_layout"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    android:fitsSystemWindows="true">

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

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_height="match_parent"
        android:layout_width="wrap_content"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header"
        app:menu="@menu/drawer_view"/>

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

它托管了 ViewPager: include_list_viewpager.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"
    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.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_scrollFlags="scroll|enterAlways|snap"
            app:contentScrim="?attr/colorPrimary"
            app:expandedTitleMarginStart="48dp"
            app:expandedTitleMarginEnd="64dp"
            android:fitsSystemWindows="true">
            <ImageView
                android:id="@+id/image"
                android:src="@drawable/header_image"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:scaleType="centerCrop"
                android:fitsSystemWindows="true"
                app:layout_collapseMode="parallax"/>
            <View
                android:background="#AA50AA00"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                app:layout_collapseMode="parallax"/>

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

        </android.support.design.widget.CollapsingToolbarLayout>
        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:background="#50AA00"
            app:tabMode="scrollable"
            app:tabIndicatorColor="#FFF"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </android.support.design.widget.AppBarLayout>

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>

CollapsingToolbarLayout承载着Toolbar（app:layout_collapseMode="pin"），以及上方的ImageView（app:layout_collapseMode="parallax"）。

在ViewPager中托管的Fragment具有如下布局：

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.NestedScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:fillViewport="true"
    android:fitsSystemWindows="true"
    android:layout_gravity="fill_vertical"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <LinearLayout
        android:orientation="vertical"
        android:background="#DDD"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:padding="16dp">
            <ImageView
                android:src="@drawable/mobile"
                android:layout_marginTop="2dp"
                android:layout_width="16dp"
                android:layout_height="16dp" />
            <TextView
                android:text="@string/prepaid_recharge"
                android:layout_marginStart="16dp"
                android:layout_gravity="center_vertical"
                android:textColor="#000"
                android:fontFamily="sans-serif-medium"
                android:textSize="14sp"
                android:textAllCaps="true"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />
        </LinearLayout>
        ........
        <ListView
            android:id="@+id/recent_recharge_list"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>
    </LinearLayout>
</android.support.v4.widget.NestedScrollView>

所以它具有这种行为 app:layout_behavior="@string/appbar_scrolling_view_behavior" 并且填充了 ViewPort (android:fillViewport="true")

实际上，这就是你需要的全部。 Fragment 类非常标准：

public class RechargeFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.recharge_fragment, container, false);
    }
}

Activity非常标准。

同样，您可以在此处找到我的代码示例。

NB！我发现它在模拟器上效果非常差（一点都不流畅）。

希望能对您有所帮助。

- Konstantin Loginov

---

@KushminderGarg 你有没有在真实设备上测试过，而不是模拟器？ 它完全可以正常工作，就像你在gif中看到的那样。（我在生产中有类似的代码，还没有人抱怨滚动） - Konstantin Loginov

我正在真机上测试，而不是模拟器上。 - Kushminder Garg

完全不流畅，它会卡住 :( 这实际上让我回到了现实。 - Harry Sharma

@eRaisedToX - 可能不需要在滚动视图中嵌套ViewPager？并确保ViewPager具有“app:layout_behavior = @string/appbar_scrolling_view_behavior”属性。 - Konstantin Loginov

这并没有解决原始的错误，被接受的答案应该是 https://dev59.com/vVwZ5IYBdhLWcg3wJ9Yp ，将NestedScrollView的直接子项clickable=true。 - AntPachon

Answer 2

在使用CoordinatorLayout时，我遇到了类似的问题，其中包含AppbarLayout、CollapsingToolbarLayout和NestedScrollView作为子视图。

以下代码是直接从我的项目工作空间中提取的工作代码。希望能对你有所帮助！

<?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"
    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.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:contentScrim="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">
            <ImageView
                android:id="@+id/cover_pic"
                android:layout_width="match_parent"
                android:layout_height="256dp"
                android:scaleType="centerCrop"
                app:layout_collapseMode="parallax"
                android:src="@drawable/cookin"/>
            <android.support.v7.widget.Toolbar
                android:id="@+id/mToolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:layout_collapseMode="pin"/>

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


        <android.support.design.widget.TabLayout
            android:id="@+id/tabLayout"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:layout_gravity="bottom"
            android:background="?attr/colorPrimary"
            app:tabMode="scrollable"/>

    </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">

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

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_alignParentBottom="true"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <android.support.design.widget.FloatingActionButton
                android:id="@+id/fab_phone"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="bottom|end"
                android:layout_marginRight="@dimen/fab_margin"
                android:visibility="invisible"
                app:backgroundTint="@color/colorFAB2"
                app:elevation="6dp"
                android:layout_margin="5dp"
                app:pressedTranslationZ="12dp"
                android:src="@drawable/ic_phone_white_24dp" />

            <android.support.design.widget.FloatingActionButton
                android:id="@+id/fab_book"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="bottom|end"
                android:layout_margin="5dp"
                android:layout_marginRight="@dimen/fab_margin"
                android:visibility="invisible"
                app:elevation="6dp"
                app:backgroundTint="@color/colorFAB1"
                app:pressedTranslationZ="12dp"
                android:src="@drawable/ic_receipt_white_24dp" />
            <android.support.design.widget.FloatingActionButton
                android:id="@+id/fab_add"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="bottom|end"
                app:elevation="6dp"
                app:backgroundTint="@color/colorAccent"
                app:pressedTranslationZ="12dp"
                android:layout_margin="@dimen/fab_margin"
                android:src="@drawable/ic_add_white_24dp" />

        </LinearLayout>

    </RelativeLayout>


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

- ishwor kafley

---

它能让我在“视图翻页器”内滚动内容吗？ - eRaisedToX

这不允许我在ViewPager中滚动内容。直接滚动会影响工具栏并使其折叠，但ViewPager内的内容保持静态。 - eRaisedToX

Answer 3

在NestedScrollView的子视图中尝试使用android:clickable="true"，就像下面这样：

    <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"
            android:clickable="true">
        </LinearLayout>
   </android.support.v4.widget.NestedScrollView>

- Yugal Modi

Answer 4

看起来是 这个的重复。虽然它指向了一个“已解决”的线程，但另一个更与RecyclerView相关。

I've wrote my behavior based on solutions made by Manolo Garcia and Kirill Boyarshinov from RecyclerView thread. In my case onNestedFling() was not called when making up fling gesture so I hacked onNestedPreScroll(). I've been working inside ViewPager with NestedScroll today, haven't tested below solution in different scenario (although it is based on similar code I wrote for RecyclerView a year ago).

First updated behavior (add it in xml as app:layout_behavior="your.package.FlingBehavior"> for android.support.design.widget.AppBarLayout):

public final class FlingBehavior extends AppBarLayout.Behavior {

    private static final String TAG = FlingBehavior.class.getName();
    private static final int TOP_CHILD_FLING_THRESHOLD = 1;
    private static final float OPTIMAL_FLING_VELOCITY = 3500;
    private static final float MIN_FLING_VELOCITY = 20;

    boolean shouldFling = false;
    float flingVelocityY = 0;

    public FlingBehavior() {
    }

    public FlingBehavior(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target,
                                  int velocityX, int velocityY, int[] consumed) {

        super.onNestedPreScroll(coordinatorLayout, child, target, velocityX, velocityY, consumed);

        if (velocityY > MIN_FLING_VELOCITY) {
            shouldFling = true;
            flingVelocityY = velocityY;
        } else {
            shouldFling = false;
        }
    }

    @Override
    public void onStopNestedScroll(CoordinatorLayout coordinatorLayout, AppBarLayout abl, View target) {
        super.onStopNestedScroll(coordinatorLayout, abl, target);
        if (shouldFling) {
            Log.d(TAG, "onNestedPreScroll: running nested fling, velocityY is " + flingVelocityY);
            onNestedFling(coordinatorLayout, abl, target, 0, flingVelocityY, true);
        }
    }

    @Override
    public boolean onNestedFling(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target,
                                 float velocityX, float velocityY, boolean consumed) {

        if (target instanceof RecyclerView && velocityY < 0) {
            Log.d(TAG, "onNestedFling: target is recyclerView");
            final RecyclerView recyclerView = (RecyclerView) target;
            final View firstChild = recyclerView.getChildAt(0);
            final int childAdapterPosition = recyclerView.getChildAdapterPosition(firstChild);
            consumed = childAdapterPosition > TOP_CHILD_FLING_THRESHOLD;
        }

        // prevent fling flickering when going up
        if (target instanceof NestedScrollView && velocityY > 0) {
            consumed = true;
        }

        if (Math.abs(velocityY) < OPTIMAL_FLING_VELOCITY) {
            velocityY = OPTIMAL_FLING_VELOCITY * (velocityY < 0 ? -1 : 1);
        }
        Log.d(TAG, "onNestedFling: velocityY - " + velocityY + ", consumed - " + consumed);

        return super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed);
    }
}

Now it should scroll smoothly but content of NestedScrollView (and RecyclerView) can scroll before AppBarLayout is collapsed, which can look wierd. To solve it follow this answer. Make small change to use fullScroll(ScrollView.FOCUS_UP) method instead of scrollTo(0, 0) otherwise You may notice small flickering during fast scrolls, here:

AppBarLayout appBarLayout = findViewById(...);
appBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
            @Override
            public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
                shouldScroll = Math.abs(verticalOffset) == appBarLayout.getTotalScrollRange();
            }
        });
NestedScrollView nestedScrollView = findViewById(...);
nestedScrollView.setOnScrollChangeListener(new NestedScrollView.OnScrollChangeListener() {
            @Override
            public void onScrollChange(NestedScrollView v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
                if (!shouldScroll)
                    nestedScrollView.fullScroll(ScrollView.FOCUS_UP);
            }
        });

After that I called it an end, but You may want to proceed further to make it scroll even more smoothly like in Google Play, there is (I think unsolved) thread about it here.

- Darek Deoniziak

---

这是一个不错的解决方案，但由于某种原因，在滚动事件期间 NestedScrollView.OnScrollChangeListener 从未被触发。有什么想法吗？我在滚动视图上使用了 app:layout_behavior="@string/appbar_scrolling_view_behavior"，但似乎无论是否使用它都不起作用。 - Vlad

你确定事件没有被触发吗？现在在AS中，调试似乎对我来说并不总是有效，日志也是如此。我知道这可能是一个疯狂的建议，但尝试在事件中添加Toast并构建一次以测试是否显示Toast。如果上述方法不起作用，那么您的布局xml可能有问题？它应该看起来与此类似：https://pastebin.com/Wcrrv8rC - Darek Deoniziak