scrollview android内的recyclerview滚动事件

Question

我在一个Scrollview中有2个水平和1个垂直(网格布局).

<ScrollView>

<Horizontal RecyclerView/>

<Horizontal RecyclerView/>

<Vertical RecyclerView/>

</ScrollView>

以上是我的观点的示意图.

我必须在垂直recyclerviews最后一项可见时加载数据,但我无法获得垂直视图的滚动事件.

这是我的scrollviewlistener.

             recyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
                @Override
                public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                    super.onScrolled(recyclerView, dx, dy);

                    totalItemCount = gridLayoutManager.getItemCount();
                    lastVisibleItem = gridLayoutManager.findLastVisibleItemPosition();
                    if (!loading && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
                        // End has been reached
                        // Do something
                        if(onLoadMoreListener!=null) {
                            onLoadMoreListener.onLoadMore(lastVisibleItem);
                        }
                        loading = true;
                    }
                }
            });

但是这个setonscrollListener永远不会被触发.如何获得上述案例的滚动事件.

提前致谢:)

Answer 1

我遇到的问题是如何解决它:

1. 首先为滚动侦听器创建一个接口

   public interface EndlessScrollListener {
       void onScrollChanged(EndlessScrollView scrollView,int x, int y, int oldx, int oldy);
   }
   

2. 通过扩展ScrollView创建自定义ScrollView

   public class EndlessScrollView extends ScrollView
   {
       private EndlessScrollListener endlessScrollListener  = null;
       public EndlessScrollView(Context context) {
           super(context);
       }
   
       public EndlessScrollView(Context context, AttributeSet attrs, int defStyle) {
           super(context, attrs, defStyle);
       }
   
       public EndlessScrollView(Context context, AttributeSet attrs) {
           super(context, attrs);
       }
   
       public void setScrollViewListener(EndlessScrollListener endlessScrollListener) {
           this.endlessScrollListener = endlessScrollListener;
       }
   
       @Override
       protected void onScrollChanged(int l, int t, int oldl, int oldt) {
           super.onScrollChanged(l, t, oldl, oldt);
           if (endlessScrollListener != null) {
               endlessScrollListener.onScrollChanged(this, l, t, oldl, oldt);
           }
       }
   }
   

3. 然后在Fragment/Activity布局中使用EndlessScrollView而不是Default one:

   <YOUR_PACKAGE_NAME.EndlessScrollView
       android:id="@+id/my_scroll_view">
   
       <!--  your recycler views ... -->
   
   </YOUR_PACKAGE_NAME.EndlessScrollView>
   

4. 接下来,您的Activity/Fragment应该实现您在步骤1中创建的接口.

5. 将您的Activity/Fragment设置为Scroll Listener,然后像这样使用:

   public class YourActivity extends Activity implements EndlessScrollListener
   {
       @Override
       protected void onCreate(Bundle savedInstanceState) 
       {
       super.onCreate(savedInstanceState);
   
       EndlessScrollView myScrollView = (EndlessScrollView) findViewById(R.id.my_scroll_view);
       myScrollView.setScrollViewListener(this);
       }
   
       @Override
       public void onScrollChanged(EndlessScrollView scrollView, int x, int y, int oldx, int oldy) 
       {
           // We take the last son in the scrollview
           View view = scrollView.getChildAt(scrollView.getChildCount() - 1);
           int distanceToEnd = (view.getBottom() - (scrollView.getHeight() + scrollView.getScrollY()));
   
           // if diff is zero, then the bottom has been reached
           if (distanceToEnd == 0) {
   
               // do stuff your load more stuff
   
           }
       }
   }