最近发现项目中一个使用CoordinatorLayout+AppBarLayout的界面发生了滑动不顺畅的问题，界面中使用了CoordinatorLayout，AppBarLayout，CollapsingToolbarLayout，Toolbar，RecyclerView，当向上滑动AppBarLayout并在惯性滑动未停止的时候滑动RecyclerView发生回弹

一、xml布局文件

<?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/behavior_demo_coordinatorLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        app:elevation="0dp"
        app:layout_behavior="com.example.utils.FlingBehavior">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/main.collapsing"
            android:layout_width="match_parent"
            android:layout_height="250dp"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:expandedTitleMarginEnd="64dp"
            app:expandedTitleMarginStart="48dp"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <!--其他布局-->
            <ImageView
                android:id="@+id/main.backdrop"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:fitsSystemWindows="true"
                android:scaleType="centerCrop"
                android:src="@drawable/img_bg"
                app:layout_collapseMode="parallax" />

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

                <RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:paddingTop="15dp">

                    <ImageView
                        android:id="@+id/iv_back"
                        android:layout_width="wrap_content"
                        android:layout_height="match_parent"
                        android:paddingStart="15dp"
                        android:paddingEnd="15dp"
                        android:src="@drawable/ic_arrow_back_white_24dp" />

                    <ImageView
                        android:layout_width="wrap_content"
                        android:layout_height="match_parent"
                        android:layout_alignParentRight="true"
                        android:paddingStart="15dp"
                        android:paddingEnd="15dp"
                        android:src="@drawable/ic_apps_white_24dp" />

                </RelativeLayout>
            </android.support.v7.widget.Toolbar>
        </android.support.design.widget.CollapsingToolbarLayout>

        <android.support.design.widget.TabLayout
            android:id="@+id/tabs"
            android:layout_width="match_parent"
            android:layout_height="40dp"
            android:layout_alignParentBottom="true"
            android:background="?attr/colorPrimary"
            app:tabIndicatorColor="@color/colorAccent"
            app:tabIndicatorHeight="4dp"
            app:tabSelectedTextColor="#000"
            app:tabTextColor="#fff" />
    </android.support.design.widget.AppBarLayout>

    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent" />


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

app:layout_behavior="com.example.utils.FlingBehavior"这个是自定义的用来解决抖动问题

二、解决办法

自定义AppBarLayout.Behavior

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

    public FlingBehavior() {
        super();
    }

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



    //fling上滑appbar然后迅速fling下滑recycler时, HeaderBehavior的mScroller并未停止, 会导致上下来回晃动
    @Override
    public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, int dx, int dy, int[] consumed, int type) {
        if (type == ViewCompat.TYPE_NON_TOUCH && getTopAndBottomOffset() == 0) { //recyclerview的惯性比较大 ,会顶在头部一会儿, 到头直接干掉它的滑动
            ViewCompat.stopNestedScroll(target, type);
        }
        super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type);
    }

    @Override
    public boolean onInterceptTouchEvent(CoordinatorLayout parent, AppBarLayout child, MotionEvent ev) {
        if (ev.getAction() == ACTION_DOWN) {
            Object scroller = getSuperSuperField(this, "mScroller");
            if (scroller != null && scroller instanceof OverScroller) {
                OverScroller overScroller = (OverScroller) scroller;
                overScroller.abortAnimation();
            }
        }

        return super.onInterceptTouchEvent(parent, child, ev);
    }

    private Object getSuperSuperField(Object paramClass, String paramString) {
        Field field = null;
        Object object = null;
        try {
            field = paramClass.getClass().getSuperclass().getSuperclass().getDeclaredField(paramString);
            field.setAccessible(true);
            object = field.get(paramClass);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return object;
    }
    // --------------------------- end
}