This blog uses for reference. Qi Bin The Great God's, The correct way to add headers to RecyclerView
This blog uses for reference. Qi Bin The Great God's, The correct way to add headers to RecyclerView
I want to make a contact interface similar to Wechat. The solution I came up with is to add header and footer to recyclerView.
The results are as follows: (The interface is ugly, spray lightly)
The pit was also encountered when adding footer. At first, the getItemViewType method was modified directly to get footer type, and the onCreateViewHolder method was added to create footer's ViewHolder.
@Override public int getItemViewType(int position) { if (mHeaderView == null) return TYPE_NORMAL; if (position == 0) return TYPE_HEADER; if (mFooterView == null) return TYPE_NORMAL; if (position == getItemCount() - 1) return TYPE_FOOTER; return TYPE_NORMAL; }
@Override public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, final int viewType) { if (mFooterView != null && viewType == TYPE_FOOTER) return new ViewHolder(mFooterView); if (mHeaderView != null && viewType == TYPE_HEADER) return new ViewHolder(mHeaderView); return onCreate(parent, viewType); }
After making 10 false data, dragging can only see 8 data. Imagine that there must be a problem with the return value of the total getItemCount method.
@Override
public int getItemCount() {
int itemCount = mDatas.size();
if (mHeaderView != null ) {
itemCount ++ ;
}
if (mFooterView != null) {
itemCount ++;
}
return itemCount;
}I haven't found the problem for a long time, but debug found that the first line of code in onBindViewHolder carried out the return of header type Item, and I think I should add it myself.
Because what I do is contacts, I need to rebind the data after adding contacts, so I add onBindData method to reassign the data of recyclerView.@Override public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) { //Prevent ClassCastException if (getItemViewType(position) == TYPE_HEADER) return; if (getItemViewType(position) == TYPE_FOOTER) return; int pos = getRealPosition(viewHolder); T data = null; //Empty the data to avoid anomalies if (mDatas != null && mDatas.size() > 0) { data = mDatas.get(pos); onBind(viewHolder, pos, data); } if (mListener != null) { final T finalData = data; final int finalPos = pos; viewHolder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { mListener.onItemClick(finalPos, finalData); } }); } }
The overall code is as follows:
public abstract class BaseRecyclerAdapter<T> extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
public static final int TYPE_HEADER = 0;
public static final int TYPE_NORMAL = 1;
public static final int TYPE_FOOTER = 2;
public Context context;
public List<T> mDatas;
public BaseRecyclerAdapter(Context context, List<T> datas) {
this.context = context;
this.mDatas = datas;
}
private View mHeaderView;
public View mFooterView;
private OnItemClickListener mListener;
public void setOnItemClickListener(OnItemClickListener listener) {
mListener = listener;
}
/**
* You can add headerView only once
* @param headerView
*/
public void setHeaderView(View headerView) {
mHeaderView = headerView;
notifyItemInserted(0);
}
public View getHeaderView() {
return mHeaderView;
}
/**
* You can add footView only once
* @param footerView
*/
public void setFooterView(View footerView) {
mFooterView = footerView;
notifyItemInserted(getItemCount());
}
public View getFooterView() {
return mFooterView;
}
@Override
public int getItemViewType(int position) {
if (mHeaderView == null) return TYPE_NORMAL;
if (position == 0) return TYPE_HEADER;
if (mFooterView == null) return TYPE_NORMAL;
if (position == getItemCount() - 1) return TYPE_FOOTER;
return TYPE_NORMAL;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, final int viewType) {
if (mFooterView != null && viewType == TYPE_FOOTER) return new ViewHolder(mFooterView);
if (mHeaderView != null && viewType == TYPE_HEADER) return new ViewHolder(mHeaderView);
return onCreate(parent, viewType);
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
//Prevent ClassCastException
if (getItemViewType(position) == TYPE_HEADER) return;
if (getItemViewType(position) == TYPE_FOOTER) return;
int pos = getRealPosition(viewHolder);
T data = null;
//Empty the data to avoid anomalies
if (mDatas != null && mDatas.size() > 0) {
data = mDatas.get(pos);
onBind(viewHolder, pos, data);
}
if (mListener != null) {
final T finalData = data;
final int finalPos = pos;
viewHolder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mListener.onItemClick(finalPos, finalData);
}
});
}
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
if (manager instanceof GridLayoutManager) {
final GridLayoutManager gridManager = ((GridLayoutManager) manager);
gridManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
return getItemViewType(position) == TYPE_HEADER
? gridManager.getSpanCount() : 1;
}
});
}
}
@Override
public void onViewAttachedToWindow(RecyclerView.ViewHolder viewHolder) {
super.onViewAttachedToWindow(viewHolder);
ViewGroup.LayoutParams lp = viewHolder.itemView.getLayoutParams();
if (lp != null
&& lp instanceof StaggeredGridLayoutManager.LayoutParams) {
StaggeredGridLayoutManager.LayoutParams p = (StaggeredGridLayoutManager.LayoutParams) lp;
p.setFullSpan(viewHolder.getLayoutPosition() == 0);
}
}
/**
* Get the real position
* @param holder
* @return
*/
public int getRealPosition(RecyclerView.ViewHolder holder) {
int position = holder.getLayoutPosition();
return mHeaderView == null ? position : position - 1;
}
/**
* Get the total number of item s in recyclerView
*/
@Override
public int getItemCount() {
int itemCount = mDatas.size();
if (mHeaderView != null ) {
itemCount ++ ;
}
if (mFooterView != null) {
itemCount ++;
}
return itemCount;
}
/**
* Get the total number of real data in recyclerView
*/
public int getRealItemCount(){
return mDatas.size();
}
public abstract RecyclerView.ViewHolder onCreate(ViewGroup parent, final int viewType);
public abstract void onBind(RecyclerView.ViewHolder viewHolder, int realPosition, T data);
public abstract void bindDatas(List<T> allNewFriend);
public class ViewHolder extends RecyclerView.ViewHolder {
public ViewHolder(View itemView) {
super(itemView);
}
}
public interface OnItemClickListener<T> {
void onItemClick(int position, T data);
}
}public class AddressListPagerAdapter extends BaseRecyclerAdapter<Friend> {
public AddressListPagerAdapter(Context context, List<Friend> datas) {
super(context, datas);
}
@Override
public RecyclerView.ViewHolder onCreate(ViewGroup parent, int viewType) {
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.address_list_item, parent, false);
return new ViewHolder(itemView);
}
@Override
public void onBind(RecyclerView.ViewHolder viewHolder, int realPosition, Friend data) {
((ViewHolder) viewHolder).tv_friend_name.setText(mDatas.get(realPosition).getUsername());
RequestOptions requestOptions = new RequestOptions()
.placeholder(R.drawable.head)
.error(R.drawable.default_head);
Glide.with(context).load(mDatas.get(realPosition).getHeaderImage())
.apply(requestOptions)
.into(((ViewHolder) viewHolder).iv_head_portrait);
}
@Override
public void bindDatas(List<Friend> allNewFriend) {
mDatas = allNewFriend;
}
public class ViewHolder extends BaseRecyclerAdapter.ViewHolder {
private ImageView iv_head_portrait;
private TextView tv_friend_name;
public ViewHolder(View itemView) {
super(itemView);
iv_head_portrait = (ImageView) itemView.findViewById(R.id.iv_head_portrait);
tv_friend_name = (TextView) itemView.findViewById(R.id.tv_friend_name);
}
}
}
Adding Header and Footer direct calls, setHeaderView and setFooterView methods can be used. Header and footer click events are not processed in recyclerView, they need to be set up by themselves. Personally, it is better to handle the click events separated from the header and footer of recyclerView. Personal views may be a bit one-sided, but it should be analyzed in detail.
The only pity is that viewHolder needs to be forced to bind data in onBind. In addition, such a method can only add a header and a footer, if you want to add more, you can add the corresponding view to the header and footer. If you still can't meet your needs, you can learn from it. The Method of Hongyang-Dashen