在Android项目中使用RecyclerView实现一个上拉加载下拉刷新功能

package com.example.fly.recyclerviewrefresh.base;import android.os.Bundle;import android.support.annotation.Nullable;import android.support.v4.widget.SwipeRefreshLayout;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import com.example.fly.recyclerviewrefresh.R;import java.util.ArrayList;import java.util.List;public abstract class RefreshActivity<T extends Object,A extends RecyclerView.Adapter> extends BaseActivity implements SwipeRefreshLayout.OnRefreshListener { protected SwipeRefreshLayout swipeRefreshLayout; protected RecyclerView recyclerView; protected LinearLayoutManager linearLayoutManager; protected A adapter; protected List<T> lists = new ArrayList<>(); protected T dataBeanLoadMore = createBean(); protected boolean isLoadDataIng; // 默认为false 是否正在加载数据， false 不在加载， true 正在加载 protected boolean isScrollY; // 是否在Y轴（垂直方向）上滑动， false 没滑动， true 滑动 @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(setLayout()); swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipeRefreshLayout); swipeRefreshLayout.setOnRefreshListener(this); swipeRefreshLayout.setColorSchemeResources(Refresh.colors); // 设置变化的颜色 recyclerView = (RecyclerView) findViewById(R.id.recyclerView); linearLayoutManager = new LinearLayoutManager(this); recyclerView.setLayoutManager(linearLayoutManager); loadMore(); }  protected abstract int setLayout(); public abstract T createBean();// public abstract A createAdapter();  protected void loadMore() { recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {  @Override public void onScrollStateChanged(RecyclerView recyclerView, int newState) { super.onScrollStateChanged(recyclerView, newState); if (newState == RecyclerView.SCROLL_STATE_IDLE && isLoadDataIng == false ) {  int lastVisibleItem = linearLayoutManager.findLastCompletelyVisibleItemPosition(); // 获取最后一个item的角标  int totalItemCount = linearLayoutManager.getItemCount(); // 获取item的总数  if (lastVisibleItem == (totalItemCount - 1)) { // 判断滑到最后一个item  if (!swipeRefreshLayout.isRefreshing()) { //不再下拉刷新状态  if (isScrollY) { // 在Y轴（垂直方向）上有滑动  // TODO 执行上拉加载  onShowRefresh();  loadMoreData();  }  }  } } }  @Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) { super.onScrolled(recyclerView, dx, dy); if (dy > 0) {  isScrollY = true; }else{  isScrollY = false; } } }); }  public abstract void loadMoreData();  protected void onShowRefresh() { isLoadDataIng = true; // 正在加载数据 lists.add(dataBeanLoadMore); adapter.notifyDataSetChanged(); }  protected void onHintLoadMore() { lists.remove(dataBeanLoadMore); isLoadDataIng = false; // 不在加载数据 adapter.notifyDataSetChanged(); }}