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);
}
}
}
}