RecyclerView onScrolled 根本没有被解雇

Question

我打算创建一个分页滚动到底部的 RecyclerView。但是 onScrolled 回调根本没有被触发：

    mBooksRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            Log.i("Dale", "scrolled");
        }
    });

    mBooksRecyclerView.setNestedScrollingEnabled(false);

    if (Utils.hasContent(books)) {
        mBooksRecyclerView.setVisibility(View.VISIBLE);
        BookCardViewAdapter adapter = new BookCardViewAdapter(this, books);

        final GridLayoutManager gridLayoutManager = new GridLayoutManager(BooksActivity.this, 3);
        mBooksRecyclerView.setLayoutManager(gridLayoutManager);
        mBooksRecyclerView.setAdapter(adapter);

        emptyView.setVisibility(View.GONE);
    } else {
        emptyView.setVisibility(View.VISIBLE);
        mBooksRecyclerView.setVisibility(View.GONE);
    }

我也尝试从 NestedScrollView 中删除 RecyclerView，但它仍然不起作用。

这是我的 XML 文件：

books_content.xml：

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

    <RelativeLayout
        android:id="@+id/header"
        android:layout_width="match_parent"
        android:layout_height="@dimen/books_category_height"
        android:background="@color/gfs_blue">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/categories_tab"
            android:layout_width="match_parent"
            android:layout_height="@dimen/books_category_height">

        </android.support.v7.widget.RecyclerView>
    </RelativeLayout>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/sub_categories_tab"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/header"
        android:layout_marginTop="20dp">

    </android.support.v7.widget.RecyclerView>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/books_recycler_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_below="@id/sub_categories_tab"
        android:scrollbars="vertical" />
</RelativeLayout>

activity_books.gfs：

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout 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:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">


    <RelativeLayout
        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="@color/white"
        android:fitsSystemWindows="true"
        tools:context=".activities.GFSBooksActivity">

        <include
            android:id="@+id/appbarlayout"
            layout="@layout/appbarlayout"/>

        <RelativeLayout
            android:id="@+id/empty_view"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_centerInParent="true"
            android:layout_below="@id/appbarlayout"
            android:background="@color/white"
            android:visibility="gone">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="No content found"
                android:textColor="@color/gray"
                android:textSize="20dp" />
        </RelativeLayout>

        <include
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            layout="@layout/books_content"
            android:layout_below="@+id/appbarlayout"/>
        <!--<android.support.v4.widget.NestedScrollView-->

            <!--android:layout_width="match_parent"-->
            <!--android:layout_height="match_parent"-->
            <!--app:layout_behavior="@string/appbar_scrolling_view_behavior">-->


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

    </RelativeLayout>


    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />

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

最初，它位于NestedScrollView 下，但由于提到如果RecyclerView 在NestedScrollView 或ScrollView 内，则不会调用onScroll，因此我删除了NestedScrollView。

Answer 1

我重新启动了我的 Android Studio，它现在一直在工作。但修复可能是删除 NestedScrollView 中的 RecyclerView。

Answer 2

您已禁用 RecyclerView 的滚动。因此，您将不会收到其滚动的任何事件。您需要改为添加 recyclerView 父级的滚动事件，该事件应该是 NestedScrollView 而不是 ScrollView。

Answer 3

试试这个

int pastVisibleItem, visibleItemCount, totalItemCount, currentPage = 1, mPage = 1;
private boolean loading = true;

现在用这个方法实现分页

 mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
            }

            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                //Log.e("checkkk", "cheeckk");

                visibleItemCount = recyclerView.getChildCount();
                totalItemCount = mLayoutManager.getItemCount();
                pastVisibleItem = mLayoutManager.findFirstVisibleItemPosition();
                if (loading) {
                    if ((visibleItemCount + pastVisibleItem) >= totalItemCount) {
                        loading = false;
                        currentPage++;
                        // do your stuff here
                    }
                }
            }
        });