Android 协调布局-向相反方向投掷会导致抖动

我需要制作一个顶部带有静态视图的可滚动片段，底部每个页面都有一个带有RecyclerView的ViewPager。我试图使用协调布局来实现预期的结果，但遇到了一个问题-当我向上弹出俯视图（以便向下滚动）并且在向下弹出RecyclerView（以便向上滚动）后不久，滚动有点取消和抖动；当我第一次向下滚动“回收器”视图，然后向上滚动“顶部”视图时，整个片段会滚动回顶部。当我开始反向滚动时，滚动看起来像是在进行，而不是停止

我发现了一个类似的布局（），但在尝试之后，我发现它也有同样的问题

以下是本期的录音：

编辑：在下面添加布局代码

fragment\u layout.xml

：

FakePageFragment.java

：

list\u item\u card.xml

：

---

一个与投掷行为类似的问题也得到了解决。 需要将自定义行为指定给appbar

public final class FlingBehavior extends AppBarLayout.Behavior {
private static final int TOP_CHILD_FLING_THRESHOLD = 3;
private boolean isPositive;

public FlingBehavior() {
}

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

@Override
public boolean onNestedFling(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, float velocityX, float velocityY, boolean consumed) {
    if (velocityY > 0 && !isPositive || velocityY < 0 && isPositive) {
        velocityY = velocityY * -1;
    }
    if (target instanceof RecyclerView && velocityY < 0) {
        final RecyclerView recyclerView = (RecyclerView) target;
        final View firstChild = recyclerView.getChildAt(0);
        final int childAdapterPosition = recyclerView.getChildAdapterPosition(firstChild);
        consumed = childAdapterPosition > TOP_CHILD_FLING_THRESHOLD;
    }
    return super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed);
}

@Override
public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, int dx, int dy, int[] consumed) {
    super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed);
    isPositive = dy > 0;
}
}

public final类FlingBehavior扩展了AppBarLayout.Behavior{
私有静态最终int TOP\u CHILD\u FLING\u阈值=3；
私有布尔正；
公共FlingBehavior（）{
}
公共FlingBehavior（上下文、属性集属性）{
超级（上下文，attrs）；
}
@凌驾
公共布尔onNestedFling（CoordinatorLayout CoordinatorLayout，AppBarLayout子级，视图目标，浮点速度yx，浮点速度yy，布尔消耗）{
如果（速度y>0&&isPositive | |速度y<0&&isPositive）{
velocityY=velocityY*-1；
}
if（RecyclerView和velocityY的目标实例<0）{
最终RecyclerView RecyclerView=（RecyclerView）目标；
最终视图firstChild=recyclerView.getChildAt（0）；
final int childAdapterPosition=recyclerView.getChildAdapterPosition（firstChild）；
消费=儿童适配器位置>顶部儿童投掷阈值；
}
返回super.onNestedFling（coordinatorLayout、child、target、velocityX、velocityY、consumed）；
}
@凌驾
public void onNestedPreScroll（CoordinatorLayout CoordinatorLayout，AppBarLayout子级，视图目标，int-dx，int-dy，int[]已消耗）{
super.onNestedPreScroll（协调布局、子项、目标、dx、dy、消耗）；
isPositive=dy>0；
}
}

默认的recyclerView Coordinator布局行为会出现这种情况。已经有一段时间了。我实现了这种行为，但没有效果。看起来这根本没什么区别。你提供的链接中的问题与我的不同。

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.example.ewelina.matador.R;

public class MyFragment extends android.support.v4.app.Fragment {

    public static MyFragment newInstance() {
        return new MyFragment();
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRetainInstance(true);
    }

    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        final View rootView = inflater.inflate(R.layout.fragment_layout, container, false);

        TabLayout tabLayout = rootView.findViewById(R.id.result_tabs);
        ViewPager viewPager = rootView.findViewById(R.id.view_pager);

        viewPager.setAdapter(new TabsAdapter(getChildFragmentManager()));
        tabLayout.setupWithViewPager(viewPager);

        return rootView;
    }

    private static class TabsAdapter extends FragmentPagerAdapter {
        private static final int TAB_COUNT = 2;

        TabsAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public int getCount() {
            return TAB_COUNT;
        }

        @Override
        public Fragment getItem(int i) {
            return FakePageFragment.newInstance();
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return "Tab " + String.valueOf(position);
        }
    }
}

public class FakePageFragment extends Fragment {
    private RecyclerView mRootView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        mRootView = (RecyclerView) inflater.inflate(R.layout.fragment_page, container, false);
        return mRootView;
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        initRecyclerView();
    }

    private void initRecyclerView() {
        mRootView.setAdapter(new FakePageAdapter(20));
    }

    public static Fragment newInstance() {
        return new FakePageFragment();
    }


    private static class FakePageAdapter extends RecyclerView.Adapter<FakePageVH> {
        private final int numItems;

        FakePageAdapter(int numItems) {
            this.numItems = numItems;
        }

        @Override
        public FakePageVH onCreateViewHolder(ViewGroup viewGroup, int i) {
            View itemView = LayoutInflater.from(viewGroup.getContext())
                    .inflate(R.layout.list_item_card, viewGroup, false);

            return new FakePageVH(itemView);
        }

        @Override
        public void onBindViewHolder(FakePageVH fakePageVH, int i) {
            // do nothing
        }

        @Override
        public int getItemCount() {
            return numItems;
        }
    }

    private static class FakePageVH extends RecyclerView.ViewHolder {
        FakePageVH(View itemView) {
            super(itemView);
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
    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:id="@+id/my_recycler_view"
    android:scrollbars="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layoutManager="android.support.v7.widget.LinearLayoutManager"
    tools:listitem="@layout/list_item_card"
    />

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_gravity="center"
    android:layout_width="match_parent"
    android:layout_height="200dp"
    android:layout_marginRight="8dp"
    android:layout_marginLeft="8dp"
    android:layout_marginBottom="4dp"
    android:layout_marginTop="4dp"
    >

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fontFamily="sans-serif-light"
        android:padding="8dp"
        android:text="Lorem ipsum"
        android:lineSpacingExtra="4dp"
        android:ellipsize="end"
        />
</LinearLayout>

public final class FlingBehavior extends AppBarLayout.Behavior {
private static final int TOP_CHILD_FLING_THRESHOLD = 3;
private boolean isPositive;

public FlingBehavior() {
}

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

@Override
public boolean onNestedFling(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, float velocityX, float velocityY, boolean consumed) {
    if (velocityY > 0 && !isPositive || velocityY < 0 && isPositive) {
        velocityY = velocityY * -1;
    }
    if (target instanceof RecyclerView && velocityY < 0) {
        final RecyclerView recyclerView = (RecyclerView) target;
        final View firstChild = recyclerView.getChildAt(0);
        final int childAdapterPosition = recyclerView.getChildAdapterPosition(firstChild);
        consumed = childAdapterPosition > TOP_CHILD_FLING_THRESHOLD;
    }
    return super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed);
}

@Override
public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, int dx, int dy, int[] consumed) {
    super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed);
    isPositive = dy > 0;
}
}