RecyclerView上拉加载封装代码

public abstract class BaseRecyPRAdapter<T> extends RecyclerView.Adapter<BaseRecyPRAdapter.BaseViewHolder> {  private static final String TAG = "BaseRecyPRAdapter";  public static final int VIEW_ITEM = 0;  public static final int VIEW_PROG = 1;  public List<T> mDataList;  private final Context mContext;  private final RecyclerView mRecyclerView;  private int totalItemCount;  private int lastVisibleItemPosition;  boolean isShowFootVieW = false;  private Handler handler = new Handler();  private static final int STATE_NORMAL = 0;  private static final int STATE_LOADING = 1;  private static final int STATE_LOAD_COMPLETE = 2;  private int mState = STATE_NORMAL;  public BaseRecyPRAdapter(Context context, RecyclerView recyclerView) {    mContext = context;    mRecyclerView = recyclerView;    if (mRecyclerView.getLayoutManager() instanceof LinearLayoutManager) {      final LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();      mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {        @Override        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {          super.onScrollStateChanged(recyclerView, newState);          int extent = recyclerView.computeVerticalScrollExtent();          int range = recyclerView.computeVerticalScrollRange();          Log.e(TAG, "/n extent = " + extent + "/n range = " + range);          if (range > extent) {            if(!isShowFootVieW){              notifyDataSetChanged();            }            isShowFootVieW = true;          } else {            isShowFootVieW = false;          }          totalItemCount = linearLayoutManager.getItemCount();          if (mState == STATE_NORMAL && newState == RecyclerView.SCROLL_STATE_IDLE &&              totalItemCount == lastVisibleItemPosition + 1 && range > extent) {            mState = STATE_LOADING;            handler.post(new Runnable() {              @Override              public void run() {                if (mLoadMoreDataListener != null) {                  mLoadMoreDataListener.loadMoreData();                }              }            });          }        }        @Override        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {          super.onScrolled(recyclerView, dx, dy);          lastVisibleItemPosition = linearLayoutManager.findLastVisibleItemPosition();        }      });    }  }  @Override  public BaseViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {    BaseViewHolder holder = null;    View view = null;    if (viewType == VIEW_PROG) {      view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_footer, parent, false);    } else {      view = LayoutInflater.from(parent.getContext()).inflate(getLayoutId(viewType), parent, false);    }    holder = new BaseViewHolder(view);    return holder;  }  @Override  public void onBindViewHolder(BaseViewHolder holder, int position) {    if (holder.getItemViewType() == BaseRecyPRAdapter.VIEW_PROG) {//      LogTool.LogE_DEBUG(TAG, "onBindViewHolder--->" + mState);      ProgressBar progressBar = (ProgressBar) holder.getView(R.id.progressbar);      TextView text = (TextView) holder.getView(R.id.text);      if (mState == STATE_LOAD_COMPLETE) {        progressBar.setVisibility(View.GONE);        text.setText(mContext.getString(R.string.没有数据了));      } else {        progressBar.setVisibility(View.VISIBLE);        text.setText(mContext.getString(R.string.正在加载中));      }    }    if (holder.getItemViewType() == BaseRecyPRAdapter.VIEW_ITEM) {      onBindData(holder, position);    }  }  @Override  public int getItemCount() {    if (isShowFootVieW) {      return mDataList == null ? 0 : mDataList.size() + 1;    } else {      return mDataList == null ? 0 : mDataList.size();    }  }  //根据不同的数据返回不同的viewType  @Override  public int getItemViewType(int position) {    if (mDataList == null)      return VIEW_ITEM;    if (position == mDataList.size()) {      return VIEW_PROG;    } else {      return VIEW_ITEM;    }  }  /**   * 根据type 返回不同的布局   *   * @param type   * @return   */  public abstract int getLayoutId(int type);  public abstract void onBindData(BaseViewHolder holder, int position);  public static class BaseViewHolder extends RecyclerView.ViewHolder {    private Map<Integer, View> mViewMap;    public View view;    public BaseViewHolder(View itemView) {      super(itemView);      view = itemView;      mViewMap = new HashMap<>();    }    /**     * 获取设置的view     *     * @param id     * @return     */    public View getView(int id) {      View view = mViewMap.get(id);      if (view == null) {        view = itemView.findViewById(id);        mViewMap.put(id, view);      }      return view;    }  }  public void stopLoadMore() {    mState = STATE_NORMAL;    notifyDataSetChanged();  }  public void loadComplete() {    mState = STATE_LOAD_COMPLETE;    notifyItemChanged(getItemCount()-1);  }  public void setData(List<T> datas) {    mDataList = datas;  }  private LoadMoreDataListener mLoadMoreDataListener;  public void setLoadMoreDataListener(LoadMoreDataListener mLoadMoreDataListener) {    this.mLoadMoreDataListener = mLoadMoreDataListener;  }  public interface LoadMoreDataListener {    void loadMoreData();  }}

public class MainActivity extends AppCompatActivity {  private static final String TAG = "RecyActivity";  private RecyclerView mRecyclerView;  private List<String> list = new ArrayList<>();  private MyRecyViewAdapter mAdapter;  private Handler handler = new Handler();  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    init();  }  private void init() {    initView();    initData();    initListener();  }  private void initView() {    mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);    //创建一个LinearLayoutManager对象    LinearLayoutManager linearLayoutManager = new LinearLayoutManager(        this, LinearLayoutManager.VERTICAL, false);    mRecyclerView.setLayoutManager(linearLayoutManager);    //创建adapter对象    mAdapter = new MyRecyViewAdapter(this, mRecyclerView);    mRecyclerView.setAdapter(mAdapter);    mAdapter.setData(list);//设置数据  }  //初始化数据  private void initData() {    for (int i = 0; i < 15; i++) {      list.add("DATA---------->" + i);    }  }  //初始化监听  private void initListener() {    //加载更多回调监听    mAdapter.setLoadMoreDataListener(new BaseRecyPRAdapter.LoadMoreDataListener() {      @Override      public void loadMoreData() {        //加入null值此时adapter会判断item的type        Log.e(TAG, "loadMoreData--->");        handler.postDelayed(new Runnable() {          @Override          public void run() {            if (list.size() < 30) {              for (int i = 0; i < 5; i++) {                list.add("LOAD MORE DATA---------->" + i);              }              mAdapter.stopLoadMore();            } else {              mAdapter.loadComplete();            }          }        }, 500);      }    });  }  class MyRecyViewAdapter extends BaseRecyPRAdapter<String> {    public MyRecyViewAdapter(Context context, RecyclerView recyclerView) {      super(context, recyclerView);    }    @Override    public int getLayoutId(int type) {      return R.layout.item_view;    }    @Override    public void onBindData(BaseViewHolder holder, int position) {      Log.e(TAG, "onBindData--->" + position);      if (mDataList == null || mDataList.isEmpty())        return;      TextView tv = (TextView) holder.getView(R.id.tv_name);      if (tv != null) {        tv.setText("DATA--------->" + position);      }    }  }}