NestedScrollView with webView rendering only in NestedScrollView

Question

Below, my code handles the correct behavior of my actionBar / toolbar / tabBar and nestedScrollView applications using the ViewPager (webView) inside it. ViewPager is basically a regular webView.

Everything works fine, except that ViewPager cannot be scrolled vertically. Only NestedScrollView scrolls. I want the same behavior as the Facebook application, if you scroll through the feed (webView), the tabBar moves the panel up vertically.

 

<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"
    tools:context=".ui.activity.FragmentContainer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    >

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        >
                <android.support.v7.widget.Toolbar
                    android:id="@+id/toolbar"
                    app:theme="@style/M.Toolbar"
                    app:popupTheme="@style/M.Toolbar.PopupTheme"
                    android:layout_width="match_parent"
                    android:layout_height="?attr/actionBarSize"
                    app:layout_scrollFlags="scroll|enterAlways"
                    >
                </android.support.v7.widget.Toolbar>

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

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

    <android.support.v4.widget.NestedScrollView
        android:layout_height="match_parent"
        android:layout_width="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        android:background="@android:color/transparent"
        android:fillViewport="true"
        >

    <com.m.ui.util.EdgeScrollViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/transparent"
        android:visibility="visible"
        >

    </com.m.ui.util.EdgeScrollViewPager>

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

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

So, to be able to scroll through my viewPager (webView), I added a new class that extends webView:

public class TouchyWebView extends WebView {

    public TouchyWebView(Context context) {
        super(context);
    }

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

    public TouchyWebView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event){
        requestDisallowInterceptTouchEvent(true);
        return super.onTouchEvent(event);
    }
}

viewPager (webView), . , NestedScrollView tabBar/ . webView tabBar. viewPager (webView), NestedScrollView (tabBar/toolbar)?

-

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/white">

    <com.m.ui.base.TouchyWebView
        android:id="@+id/web_webview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/transparent"
        android:visibility="visible" />

    <LinearLayout
        android:id="@+id/web_loadingview"
        android:orientation="vertical"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="gone"
        android:layout_gravity="center">

        <ProgressBar
            style="?android:attr/progressBarStyleLarge"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:indeterminate="true"
            android:visibility="visible"
            android:layout_gravity="center"/>
    </LinearLayout>

</FrameLayout>

Answer 1

, :

class NestedScrollWebView constructor(
        context: Context,
        attrs: AttributeSet): WebView(context, attrs), NestedScrollingChild2 {

    private var lastMotionY = 0
    private var nestedYOffset = 0
    private val scrollOffset = IntArray(2)
    private val scrollConsumed = IntArray(2)
    private val childHelper = NestedScrollingChildHelper(this)

    init {
        isNestedScrollingEnabled = true
    }

    override fun onTouchEvent(event: MotionEvent?): Boolean {
        if (event == null) return false

        val motionEvent = MotionEvent.obtain(event)
        val currentY = event.y.toInt()

        when (event.action) {
            MotionEvent.ACTION_DOWN -> {
                nestedYOffset = 0
                lastMotionY = currentY
                startNestedScroll(View.SCROLL_AXIS_VERTICAL)
            }

            MotionEvent.ACTION_MOVE -> {
                var deltaY = lastMotionY - currentY

                if (dispatchNestedPreScroll(0, deltaY, scrollConsumed, scrollOffset)) {
                    deltaY -= scrollConsumed[1]
                    motionEvent.offsetLocation(0f, scrollOffset[1].toFloat())
                    nestedYOffset += scrollOffset[1]
                }

                lastMotionY = currentY - scrollOffset[1]

                val oldY = scrollY
                val newScrollY = Math.max(0, oldY + deltaY)
                val dyConsumed = newScrollY - oldY
                val dyUnconsumed = deltaY - dyConsumed

                if (dispatchNestedScroll(0, dyConsumed, 0, dyUnconsumed, scrollOffset)) {
                    lastMotionY -= scrollOffset[1]
                    motionEvent.offsetLocation(0f, scrollOffset[1].toFloat())
                    nestedYOffset += scrollOffset[1]
                }

                motionEvent.recycle()
            }

            MotionEvent.ACTION_POINTER_DOWN,
            MotionEvent.ACTION_UP,
            MotionEvent.ACTION_CANCEL -> stopNestedScroll()

            else -> { }
        }

        return super.onTouchEvent(event)
    }

    override fun startNestedScroll(axes: Int, type: Int) = childHelper.startNestedScroll(axes, type)

    override fun stopNestedScroll(type: Int) = childHelper.stopNestedScroll(type)

    override fun hasNestedScrollingParent(type: Int) = childHelper.hasNestedScrollingParent(type)

    override fun dispatchNestedPreScroll(dx: Int, dy: Int, consumed: IntArray?, offsetInWindow: IntArray?, type: Int) =
            childHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow, type)

    override fun dispatchNestedScroll(dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, offsetInWindow: IntArray?, type: Int) =
            childHelper.dispatchNestedScroll(dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed, offsetInWindow, type)

}

WebView:

<com.widget.NestedScrollWebView
    android:id="@+id/webview"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior" />

Answer 2

,   NestedScrollview XML .

 android:fillViewport="true"

   webview.

<WebView
    android:id="@+id/webview"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"/>

Answer 3

I had a similar problem and it was solved using setFillViewport (true) Part of my code

 NestedScrollView scrollView = (NestedScrollView) findViewById (R.id.nest_scrollview);
    scrollView.setFillViewport (true);

And inside the fragment I had a list of View, where I was sitting android:nestedScrollingEnabled="true".. Fixed a problem with scrolling