RecyclerView 添加 Header 和 Footer

RecyclerView并不像listView 那样有方法可以直接添加 footer或者header 所有我们只能通过另一种方式来添加了

下面看代码

public class HeaderAndFooterAdapter<T extends RecyclerView.Adapter> extends RecyclerView.Adapter<RecyclerView.ViewHolder> {    private final T mBase;    private List<View> headers = new ArrayList<>();    private List<View> footers = new ArrayList<>();    private final int headerType = -1000;    private final int footerType = -2000;    public HeaderAndFooterAdapter(T base){        mBase = base;    }    @Override    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {                if(isHeader(viewType)){                      RecyclerView.ViewHolder viewHolder = new RecyclerView.ViewHolder(headers.get(viewType - headerType)) {            };            return viewHolder;        }else if(isFooter(viewType)){                  RecyclerView.ViewHolder viewHolder = new RecyclerView.ViewHolder(footers.get(viewType - footerType)) {            };            return viewHolder;        }else {            return mBase.onCreateViewHolder(parent, viewType);        }    }    @Override    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {        if (position < headers.size()) {        } else if (position < headers.size() + mBase.getItemCount()) {            mBase.onBindViewHolder(holder, position - headers.size());        } else {        }    }    @Override    public int getItemCount() {        return headers.size() + footers.size() + mBase.getItemCount();    }    private boolean isHeader(int viewType){        return viewType >= headerType && viewType < headerType + headers.size();    }    private boolean isFooter(int viewType){        return viewType >= footerType && viewType < footerType + footers.size();    }    @Override    public int getItemViewType(int position) {        if(position < headers.size()){            return headerType + position;        }else if(position < headers.size() + mBase.getItemCount()){            return mBase.getItemViewType(position - headers.size());        }else {            return footerType + position;        }    }    public void addHeader(View view){        headers.add(view);    }

}

上面 其实也就是 通过 判断 item的位置  例如getItemViewType方法中 如果 position < headers.size 证明他是 headerView

然后返回viewType  其他方法中就可以通过这个 getItemViewType 来进行处理了