带有RecyclerView的Android ViewPager在底部工作不正常

当我尝试滚动列表时，有时这会不正确-BottomSheet截获滚动事件并隐藏

如何重现这一点：

开底板

更改ViewPager的页面

尝试滚动列表

结果：将隐藏底页

以下是示例代码：

编译'com.android.support:design:23.4.0'

MainActivity.java

package com.nkdroid.bottomsheetsample;

import android.os.Bundle;
import android.support.design.widget.BottomSheetBehavior;
import android.support.design.widget.TabLayout;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

public
class MainActivity
        extends AppCompatActivity
{

    private BottomSheetBehavior behavior;

    @Override
    protected
    void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final Button btnView = (Button) findViewById(R.id.btnView);
        btnView.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public
            void onClick(final View v) {
                behavior.setState(BottomSheetBehavior.STATE_EXPANDED);
            }
        });

        final View bottomSheet = findViewById(R.id.bottom_sheet);
        behavior = BottomSheetBehavior.from(bottomSheet);

        final ViewPager viewPager = (ViewPager) findViewById(R.id.viewPager);
        viewPager.setAdapter(new MyPagerAdapter());

        final TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);


    }

    private
    class MyPagerAdapter
            extends PagerAdapter
    {
        @Override
        public
        int getCount() {
            return 15;
        }

        @Override
        public
        Object instantiateItem(final ViewGroup container, final int position) {
            final RecyclerView recyclerView = new RecyclerView(MainActivity.this);

            recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
            recyclerView.setAdapter(new ItemAdapter());

            container.addView(recyclerView);
            return recyclerView;
        }

        @Override
        public
        boolean isViewFromObject(final View view, final Object object) {
            return view.equals(object);
        }

        @Override
        public
        void destroyItem(final ViewGroup container, final int position, final Object object) {
            container.removeView((View) object);
        }

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

    public
    class ItemAdapter
            extends RecyclerView.Adapter<ItemAdapter.ViewHolder>
    {

        @Override
        public
        ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
            return new ViewHolder(new TextView(MainActivity.this));
        }

        @Override
        public
        void onBindViewHolder(final ViewHolder holder, final int position) {
        }

        @Override
        public
        int getItemCount() {
            return 100;
        }

        public
        class ViewHolder
                extends RecyclerView.ViewHolder
        {
            public TextView textView;

            public
            ViewHolder(final View itemView) {
                super(itemView);
                textView = (TextView) itemView;
            }
        }
    }
}

package com.nkdroid.bottomsheetsample；
导入android.os.Bundle；
导入android.support.design.widget.BottomSheetBehavior；
导入android.support.design.widget.TabLayout；
导入android.support.v4.view.PagerAdapter；
导入android.support.v4.view.ViewPager；
导入android.support.v7.app.AppActivity；
导入android.support.v7.widget.LinearLayoutManager；
导入android.support.v7.widget.RecyclerView；
导入android.view.view；
导入android.view.ViewGroup；
导入android.widget.Button；
导入android.widget.TextView；
公众的
班级活动
扩展AppCompative活动
{
私人行为；
@凌驾
受保护的
创建时无效（最终捆绑包保存状态）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
最终按钮btnView=（按钮）findViewById（R.id.btnView）；
btnView.setOnClickListener（新视图.OnClickListener（）
{
@凌驾
公众的
void onClick（最终视图v）{
behavior.setState（behavior.STATE_扩展）；
}
});
最终视图底图=findViewById（R.id.底图）；
行为=底部板材行为。从（底部板材）；
final ViewPager ViewPager=（ViewPager）findviewbyd（R.id.ViewPager）；
setAdapter（新的MyPagerAdapter（））；
最终TabLayout TabLayout=（TabLayout）findviewbyd（R.id.tabs）；
tabLayout.setupWithViewPager（viewPager）；
}
私有的
类MyPagerAdapter
扩展页雷达
{
@凌驾
公众的
int getCount（）{
返回15；
}
@凌驾
公众的
对象实例化项（最终视图组容器，最终int位置）{
最终RecyclerView RecyclerView=新的RecyclerView（MainActivity.this）；
setLayoutManager（新的LinearLayoutManager（MainActivity.this））；
setAdapter（newitemAdapter（））；
container.addView（recyclerView）；
返回回收视图；
}
@凌驾
公众的
布尔值isViewFromObject（最终视图，最终对象）{
返回视图.equals（对象）；
}
@凌驾
公众的
void destroyItem（最终视图组容器、最终int位置、最终对象）{
container.removeView（（视图）对象）；
}
@凌驾
公众的
CharSequence getPageTitle（最终整数位置）{
返回字符串.valueOf（位置）；
}
}
公众的
类项适配器
扩展RecyclerView.Adapter
{
@凌驾
公众的
ViewHolder onCreateViewHolder（最终视图组父视图，最终int视图类型）{
返回新的ViewHolder（新的TextView（MainActivity.this））；
}
@凌驾
公众的
无效onBindViewHolder（最终ViewHolder，最终int位置）{
}
@凌驾
公众的
int getItemCount（）{
返回100；
}
公众的
类视图持有者
扩展RecyclerView.ViewHolder
{
公共文本视图文本视图；
公众的
ViewHolder（最终视图项视图）{
超级（项目视图）；
textView=（textView）项目视图；
}
}
}
}

活动\u main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout android:id = "@+id/coordinatorLayout"
    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:background = "#a3b1ef"
    android:fitsSystemWindows = "true"
    tools:context = ".ui.MainActivity"
    >

    <Button
        android:id = "@+id/btnView"
        android:layout_width = "match_parent"
        android:layout_height = "wrap_content"
        android:text = "Show view"
        app:layout_behavior = "@string/appbar_scrolling_view_behavior"
        />


    <LinearLayout
        android:id = "@+id/bottom_sheet"
        android:layout_width = "match_parent"
        android:layout_height = "400dp"
        android:background = "#fff"
        android:gravity = "center"
        android:orientation = "vertical"
        app:layout_behavior = "@string/bottom_sheet_behavior"
        >


        <android.support.design.widget.TabLayout
            android:id = "@+id/tabs"
            android:layout_width = "match_parent"
            android:layout_height = "wrap_content"
            app:tabMode = "scrollable"
            />

        <android.support.v4.view.ViewPager
            android:id = "@+id/viewPager"
            android:layout_width = "match_parent"
            android:layout_height = "match_parent"
            />

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

有什么解决办法吗
 我遇到了同样的限制，但能够解决它

您所描述的效果的原因是
BottomSheetBehavior
（从v24.2.0开始）仅支持一个滚动子项，该子项在布局期间以以下方式标识：

private View findScrollingChild(View view) {
    if (view instanceof NestedScrollingChild) {
        return view;
    }
    if (view instanceof ViewGroup) {
        ViewGroup group = (ViewGroup) view;
        for (int i = 0, count = group.getChildCount(); i < count; i++) {
            View scrollingChild = findScrollingChild(group.getChildAt(i));
            if (scrollingChild != null) {
                return scrollingChild;
            }
        }
    }
    return null;
}

将库添加到依赖项：

dependencies {
    compile "biz.laenger.android:vpbs:0.0.2"
}

使用
ViewPagerBottomSheetBehavior
查看底部图纸视图：

app:layout_behavior="@string/view_pager_bottom_sheet_behavior"

在底部图纸内设置任何嵌套的ViewPager：

BottomSheetUtils.setupViewPager(bottomSheetViewPager)

（当ViewPager是底部图纸视图时，这也适用于其他嵌套的ViewPager）

这篇文章救了我的命：

在底部工作表内显示我对ViewPager的修复

package com.google.android.material.bottomsheet

import android.view.View
import androidx.annotation.VisibleForTesting
import androidx.viewpager.widget.ViewPager
import java.lang.ref.WeakReference


class BottomSheetBehaviorFix<V : View> : BottomSheetBehavior<V>(), ViewPager.OnPageChangeListener {

    override fun onPageScrollStateChanged(state: Int) {}

    override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {}

    override fun onPageSelected(position: Int) {
        val container = viewRef?.get() ?: return
        nestedScrollingChildRef = WeakReference(findScrollingChild(container))
    }

    @VisibleForTesting
    override fun findScrollingChild(view: View): View? {
        return if (view is ViewPager) {
            view.focusedChild?.let { findScrollingChild(it) }
        } else {
            super.findScrollingChild(view)
        }
    }
}

package com.google.android.material.bottomsheet
导入android.view.view
导入androidx.annotation.VisibleForTesting
导入androidx.viewpager.widget.viewpager
导入java.lang.ref.WeakReference
类BottomSheetBehaviorFix:BottomSheetBehavior（），ViewPager.OnPageChangeListener{
重写有趣的onPageScrollStateChanged（状态：Int）{}
覆盖已滚动的页面（位置：Int，位置偏移：Float，位置偏移像素：Int）{}
覆盖所选页面（位置：Int）{
val container=viewRef？.get（）？：返回
nestedScrollingChildRef=WeakReference（findScrollingChild（容器））
}
@可视性测试
覆盖有趣的findScrollingChild（视图：视图）：视图{
返回if（视图为ViewPager）{
view.focusedChild？.let{findScrollingChild（it）}
}否则{
super.findScrollingChild（视图）
}
}
}
还有一种方法不需要修改BottomSheetBehavior，而是利用BottomSheetBehavior仅识别其找到的第一个NestedScrollingEnabled的NestedScrollView这一事实。因此，与其改变BottomSheetBehavior中的逻辑，不如启用和禁用相应的滚动视图。我在这里发现了这种方法：

在我的例子中，我的行为是使用带有FragmentPagerAdapter的表格布局，所以我的Fra
package com.google.android.material.bottomsheet

import android.view.View
import androidx.annotation.VisibleForTesting
import androidx.viewpager.widget.ViewPager
import java.lang.ref.WeakReference


class BottomSheetBehaviorFix<V : View> : BottomSheetBehavior<V>(), ViewPager.OnPageChangeListener {

    override fun onPageScrollStateChanged(state: Int) {}

    override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {}

    override fun onPageSelected(position: Int) {
        val container = viewRef?.get() ?: return
        nestedScrollingChildRef = WeakReference(findScrollingChild(container))
    }

    @VisibleForTesting
    override fun findScrollingChild(view: View): View? {
        return if (view is ViewPager) {
            view.focusedChild?.let { findScrollingChild(it) }
        } else {
            super.findScrollingChild(view)
        }
    }
}

@Override
public void setPrimaryItem(@NonNull ViewGroup container, int position, @NonNull Object object) {

        super.setPrimaryItem(container, position, object);

        Fragment f = ((Fragment)object);
        String activeFragmentTag = f.getTag();
        View view = f.getView();

        if (view != null) {
            View nestedView = view.findViewWithTag("nested");               
            if ( nestedView != null && nestedView instanceof NestedScrollView) {
                ((NestedScrollView)nestedView).setNestedScrollingEnabled(true);
            }
        }

        FragmentManager fm = f.getFragmentManager();

        for(Fragment frag : fm.getFragments()) {

            if (frag.getTag() != activeFragmentTag) {
                View v = frag.getView();
                if (v!= null) {

                    View nestedView = v.findViewWithTag("nested");

                    if (nestedView!= null && nestedView instanceof NestedScrollView) {
                        ((NestedScrollView)nestedView).setNestedScrollingEnabled(false);
                    }
                }
            }
        }

        container.requestLayout();
    }

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.MLeftFragment">

    <androidx.core.widget.NestedScrollView
        android:id="@+id/nestedScrollView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:tag="nested"
        android:fillViewport="true">

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

            <!-- TODO: Update blank fragment layout -->
            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="@string/hello_mool_left_fragment" />      

        </LinearLayout>  

    </androidx.core.widget.NestedScrollView>

</androidx.constraintlayout.widget.ConstraintLayout>

package com.google.android.material.bottomsheet
import android.content.Context
import android.util.AttributeSet
import android.view.View
import androidx.annotation.VisibleForTesting
import androidx.viewpager.widget.ViewPager
import java.lang.ref.WeakReference
class ViewPagerBottomSheetBehavior<V : View>
    : com.google.android.material.bottomsheet.BottomSheetBehavior<V>,
    ViewPager.OnPageChangeListener {

    constructor() : super()
    constructor(context: Context, attrs: AttributeSet) : super(context, attrs)

    override fun onPageScrollStateChanged(state: Int) {}
    override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {}
    override fun onPageSelected(position: Int) {
        val container = viewRef?.get() ?: return
        nestedScrollingChildRef = WeakReference(findScrollingChild(container))
    }

    @VisibleForTesting
    override fun findScrollingChild(view: View?): View? {
        return if (view is ViewPager) {
            view.focusedChild?.let { findScrollingChild(it) }
        } else {
            super.findScrollingChild(view)
        }
    }
}

constructor() : super()
constructor(context: Context, attrs: AttributeSet) : super(context, attrs)

@VisibleForTesting
override fun findScrollingChild(view: View?): View? {
    return if (view is ViewPager) {
        view.focusedChild?.let { findScrollingChild(it) }
    } else {
        super.findScrollingChild(view)
    }
}

        <androidx.constraintlayout.widget.ConstraintLayout
          app:layout_behavior="com.google.android.material.bottomsheet.ViewPagerBottomSheetBehavior"
            android:layout_height="match_parent"
            android:layout_width="match_parent">
        <include
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                layout="@layout/you_content_with_a_viewPager_scroll"
        />
    </androidx.constraintlayout.widget.ConstraintLayout>


import android.content.Context
import android.util.AttributeSet
import android.view.View
import androidx.viewpager.widget.ViewPager
import java.lang.reflect.Field

class BottomSheetViewPager(context: Context, attrs: AttributeSet?) : ViewPager(context, attrs) {
    constructor(context: Context) : this(context, null)
    private val positionField: Field =
        ViewPager.LayoutParams::class.java.getDeclaredField("position").also {
            it.isAccessible = true
        }

    init {
        addOnPageChangeListener(object : SimpleOnPageChangeListener() {
            override fun onPageSelected(position: Int) {
                requestLayout()
            }
        })
    }

    override fun getChildAt(index: Int): View {
        val stackTrace = Throwable().stackTrace
        val calledFromFindScrollingChild = stackTrace.getOrNull(1)?.let {
            it.className == "com.google.android.material.bottomsheet.BottomSheetBehavior" &&
                    it.methodName == "findScrollingChild"
        }
        if (calledFromFindScrollingChild != true) {
            return super.getChildAt(index)
        }

        val currentView = getCurrentView() ?: return super.getChildAt(index)
        return if (index == 0) {
            currentView
        } else {
            var view = super.getChildAt(index)
            if (view == currentView) {
               view = super.getChildAt(0)
            }
            return view
        }
    }

    private fun getCurrentView(): View? {
        for (i in 0 until childCount) {
            val child = super.getChildAt(i)
            val lp = child.layoutParams as? ViewPager.LayoutParams
            if (lp != null) {
                val position = positionField.getInt(lp)
                if (!lp.isDecor && currentItem == position) {
                    return child
                }
            }
        }
        return null
    }
}