NestedScrollView canScrollVertically返回特定大小内容的false

Question

上下文
在我的顶部标题中,我有一个按钮,让第二个TextView为View.Visible或View.Gone.我的ViewPager内容具有特定的大小来演示我的问题,可在Nexus 5上重现.

问题
当我打开我的应用程序并向上和向下滚动内容时,我没有任何问题.然后我隐藏了我的第二个textview.
现在,如果我的手指从TextView(蓝色)或按钮(橙色)开始滚动,我就不能滚动了.但是,如果我的手指开始从白色背景滚动它是有效的.

在隐藏第二个文本上单击两次后(返回初始布局),当我滚动时,布局开始从底部开始近似地显示在40dp(appBarSize)

测试
- 替换EditText或Button通过View或TextView滚动
- 在内容添加高度和滚动的底部添加虚拟视图
- 向内容添加更多大小与上一点相同 - 在NestedScrollView(第583行)中onInterceptTouchEvent ViewCompat.canScrollVertically(this,1)返回false在这个特别高的内容大小

/*
 * Don't try to intercept touch if we can't scroll anyway.
 */
if (getScrollY() == 0 && !ViewCompat.canScrollVertically(this, 1)) {
    return false;
}

不是那么类似的问题:
由于EditText而导致NestedScrollView无法滚动
CollapsingToolBar无法处理不那么高的内容

任何帮助欢迎:)

完整代码项目(在dropbox上)

LayoutFile

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/activity_main_header_container"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#aaeeee"
        android:descendantFocusability="beforeDescendants"
        android:focusableInTouchMode="true">


        <LinearLayout
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                app:layout_scrollFlags="scroll|enterAlways">

            <EditText
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content"
                    android:layout_margin="5dp"
                    android:hint="first text"
                    android:layout_weight="1"/>

                <Button
                    android:id="@+id/hide_btn"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:enabled="true"
                    android:text="Hide second Text"
                    android:layout_weight="0"/>

                <EditText
                    android:id="@+id/second_text"
                    android:layout_width="fill_parent"
                    android:layout_height="wrap_content"
                    android:layout_margin="5dp"
                    android:hint="Second Text"
                    android:layout_marginTop="30dp"
                    android:layout_marginBottom="20dp"/>
            </LinearLayout>


        <android.support.design.widget.TabLayout
            android:id="@+id/activity_main_tab_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#cce8787c"
            app:tabGravity="fill"
            app:tabMode="fixed"/>

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

    <android.support.v4.view.ViewPager
        android:id="@+id/activity_main_content_viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">
        <android.support.v4.widget.NestedScrollView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:tag="No Scrollable"
            >

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

                <EditText
                    android:layout_width="match_parent"
                    android:layout_height="215dp"
                    android:layout_margin="20dp"
                    android:background="@android:color/holo_blue_bright"
                    android:text="First case"
                    tools:background="#456456"
                    tools:ignore="MissingPrefix"/>

                <Button
                    android:layout_width="match_parent"
                    android:layout_height="215dp"
                    android:layout_margin="20dp"
                    android:text="Second case"
                    android:background="@android:color/holo_orange_dark"/>

            </LinearLayout>
        </android.support.v4.widget.NestedScrollView>
    </android.support.v4.view.ViewPager>
</android.support.design.widget.CoordinatorLayout>

MainActivity类

public class MainActivity extends AppCompatActivity {
    private ViewPager viewPagerContent;
    private TabLayout tabLayout;
    private EditText whereText;
    private Button SearchButton;


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

        this.viewPagerContent = (ViewPager) findViewById(R.id.activity_main_content_viewpager);
        this.viewPagerContent.setAdapter(new MainContentPagerAdapter());

        this.tabLayout = (TabLayout) findViewById(R.id.activity_main_tab_layout);
        tabLayout.setupWithViewPager(viewPagerContent);

        this.whereText = (EditText) findViewById(R.id.second_text);
        this.SearchButton = (Button) findViewById(R.id.hide_btn);
        this.SearchButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                whereText.setVisibility(
                        whereText.getVisibility() == View.VISIBLE?
                                View.GONE : View.VISIBLE);
            }
        });
    }

    [...]

    private class MainContentPagerAdapter extends PagerAdapter {
        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            return container.getChildAt(position);
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
        }

        @Override
        public int getCount() {
            return viewPagerContent.getChildCount();
        }

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

        @Override
        public CharSequence getPageTitle(int position) {
            return (CharSequence) viewPagerContent.getChildAt(position).getTag();
        }
    }
}