API 19 Scrollview 没有动力

Question

我在 CoordinatorLayout 中有一个 NestedScrollView，它包含一个 recyclerView。整个片段很长，没有滚动动量，我不确定我能做些什么来修复它。我以前在更高的 Android 版本中遇到过这个问题，并且能够包含

android:nestedScrollingEnabled="false"

解决我的问题。但是，这是在 api 21 中添加的，我的项目支持 19+。对于 api 19 台设备，我的应用在这个片段上仍然没有动力。

下面是我的xml:

<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    android:background="@color/primary_color"
    android:fitsSystemWindows="true">

<android.support.v4.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="android.support.design.widget.AppBarLayout$ScrollingViewBehavior">

    <android.support.percent.PercentRelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:nestedScrollingEnabled="false">

        <ImageView
                android:id="@+id/logo"
                android:src="@drawable/logo"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="@dimen/profile_margin_medium_huge"
                android:layout_marginBottom="46dp"
                android:layout_marginRight="@dimen/activity_horizontal_margin"
                android:layout_marginLeft="@dimen/activity_horizontal_margin"
                android:layout_alignParentEnd="true"/>

        <TypefaceTextView
                android:id="@+id/textview_title"
                android:layout_below="@id/logo"
                android:text="@string/title"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                style="@style/myStyle"
                android:layout_marginLeft="@dimen/activity_horizontal_margin"
                android:layout_marginRight="@dimen/activity_horizontal_margin"
                android:layout_marginBottom="16dp"
                android:layout_alignParentLeft="true"/>

        <TypefaceTextView
                android:id="@+id/textview_byline"
                android:text="@string/byline"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                style="@style/myStyle"
                android:layout_below="@id/textview_title"
                android:layout_marginLeft="@dimen/activity_horizontal_margin"
                android:layout_marginRight="@dimen/activity_horizontal_margin"
                android:layout_marginBottom="40dp"/>

        <RadioGroup
                android:id="@+id/radiogroup_filter"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:layout_below="@id/textview_byline"
                android:layout_alignParentRight="true"
                android:layout_marginLeft="@dimen/activity_horizontal_margin"
                android:layout_marginRight="@dimen/activity_horizontal_margin"
                android:layout_marginBottom="@dimen/activity_vertical_margin">

            <TypefaceRadioButton
                    android:id="@+id/button_filter_new"
                    android:text="@string/filter_new"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    style="@style/buttonStyleRadio"
                    android:theme="@style/ButtonSecondary"
                    android:button="@null"/>

            <TypefaceRadioButton
                    android:id="@+id/button_filter_history"
                    android:text="@string/filter_history"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    style="@style/ButtonStyleRadio"
                    android:theme="@style/ButtonSecondary"
                    android:layout_alignParentRight="true"
                    android:button="@null"/>

        </RadioGroup>
        <android.support.v7.widget.RecyclerView
                android:id="@+id/recyclerview"
                android:nestedScrollingEnabled="false"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@id/radiogroup_filter"
                android:layout_marginLeft="@dimen/activity_horizontal_margin"
                android:layout_marginRight="@dimen/activity_horizontal_margin"
                android:layout_marginBottom="50dp"/>
        <android.support.percent.PercentRelativeLayout
                android:id="@+id/container_links"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@id/recyclerview"
                android:visibility="gone">
            <ImageView
                    android:id="@+id/image_link_1"
                    app:layout_widthPercent="100%"
                    app:layout_aspectRatio="158%"
                    android:scaleType="centerCrop"
                    android:layout_alignParentTop="true"/>
            <TypefaceTextView
                    android:id="@+id/text_link_1"
                    android:text="@string/text_1"
                    app:layout_widthPercent="100%"
                    app:layout_aspectRatio="158%"
                    android:gravity="bottom|left"
                    android:paddingLeft="@dimen/activity_horizontal_margin"
                    android:paddingRight="@dimen/activity_horizontal_margin"
                    android:paddingTop="32dp"
                    android:paddingBottom="32dp"
                    style="@style/myStyle"
                    android:layout_alignParentTop="true"/>
            <ImageView
                    android:id="@+id/image_link_2"
                    app:layout_widthPercent="100%"
                    app:layout_aspectRatio="158%"
                    android:scaleType="centerCrop"
                    android:layout_below="@id/image_link_1"/>
            <TypefaceTextView
                    android:id="@+id/text_link_2"
                    android:text="@string/text_2"
                    app:layout_widthPercent="100%"
                    app:layout_aspectRatio="158%"
                    android:gravity="bottom|right"
                    android:paddingLeft="@dimen/activity_horizontal_margin"
                    android:paddingRight="@dimen/activity_horizontal_margin"
                    android:paddingTop="32dp"
                    android:paddingBottom="32dp"
                    android:layout_below="@id/image_link_1"
                    style="@style/myStyle"/>
        </android.support.percent.PercentRelativeLayout>
    </android.support.percent.PercentRelativeLayout>
</android.support.v4.widget.NestedScrollView>

Answer 1

我能够在我的测试项目中重现您的症状。我修复了它，在 activity:

的 onCreate() 中添加了以下代码

final RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setOnFlingListener(new RecyclerView.OnFlingListener() {
    @Override
    public boolean onFling(int velocityX, int velocityY) {
        recyclerView.dispatchNestedFling(velocityX, velocityY, false);
        return false;
    }
});

我向 RecyclerView 添加了一个 fling 侦听器，并在 onFling() 中调用 dispatchNestedFling() 让 parent 知道正在发生一个 fling。然后，parent 可以消耗该 fling 或观察 child fling。

https://developer.android.com/reference/android/support/v4/view/NestedScrollingChild.html#dispatchNestedFling(float, float, boolean)

dispatchNestedFling

added in version 22.1.0 boolean dispatchNestedFling (float velocityX, float velocityY, boolean consumed) Dispatch a fling to a nested scrolling parent.

This method should be used to indicate that a nested scrolling child has detected suitable conditions for a fling. Generally this means that a touch scroll has ended with a velocity in the direction of scrolling that meets or exceeds the minimum fling velocity along a scrollable axis.

If a nested scrolling child view would normally fling but it is at the edge of its own content, it can use this method to delegate the fling to its nested scrolling parent instead. The parent may optionally consume the fling or observe a child fling.

这在我的模拟器上运行运行 API 19. 显然，YMMV。

Answer 2

有一个更简单的方法：

Java

recyclerView.setNestedScrollingEnabled(false);

Kotlin

recyclerView.isNestedScrollingEnabled = false

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