RecycleView想必大家都不陌生，它已他的高拓展性取代了传统布局显示，同时配合协调布局，可以实现很多意想不到的酷炫交互，今天就和大家介绍一下，如何给RecycleView添加头布局和尾布局，同时你也可以通过自己的拓展实现更多复杂的布局。
首先我们先看一下效果：
实现头部尾部布局其实方法还是很多，这里我推荐使用Adapter设置itemType来做，那么问题来了，为什么这么做呢？因为拓展性更强，并且更加解耦。将逻辑都写在adapter中，比起写在activity中管理起来也更加方便。
首先，我们需要明确一点，什么是head，什么是foot,当位于第一个item的时候就是head,最后一个就是foot.之后我们根据不同的itemType加载出来就可以了。
第一步判断头尾部以及内容区域：
private int getBodySize() {
return listData.size();
}
private boolean isHead(int position) {
return headCount!=&&position<headCount;
}
private boolean isFoot(int position) {
return footCount!=&&(position>=(getBodySize()+headCount));
}
public int getItemViewType(int position) {
if (isHead(position)) {
return HEAD_TYPE;
}else if (isFoot(position)) {
return FOOT_TYPE;
}else {
return BODY_TYPE;
}
}
根据不同的ViewType生产不同的Holder
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
switch (viewType) {
case HEAD_TYPE:
return new HeadViewHolder(mLayoutInflater.inflate(R.layout.trend_head,parent,false));
case BODY_TYPE:
return new BodyViewHolder(mLayoutInflater.inflate(R.layout.itemview_trend,parent,false));
case FOOT_TYPE:
return new FootViewHolder(mLayoutInflater.inflate(R.layout.trend_bottom,parent,false));
default:
return null;
} }
拿到不同的holder生产具体实现：
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof HeadViewHolder) { }else if (holder instanceof BodyViewHolder) {
((BodyViewHolder) holder).body.setText((CharSequence) listData.get(position-headCount)); }else if (holder instanceof FootViewHolder) { } }
怎么样是不是很简单？其实还可以拓展实现更多样式的item只需要我们设置itemtype和位置就可以了。最后附上完整代码。
public class HBRecycleViewAdapter<T> extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
private static final int HEAD_TYPE=;
private static final int BODY_TYPE=;
private static final int FOOT_TYPE=;
private int headCount=;//头部个数，后续可以自己拓展
private int footCount=;//尾部个数，后续可以自己拓展
private LayoutInflater mLayoutInflater;
private List<T>listData=new ArrayList<>();
public HBRecycleViewAdapter(Context context,List<T>listData) {
//this.context=context;
mLayoutInflater=LayoutInflater.from(context);
this.listData=listData;
}
private int getBodySize() {
return listData.size();
}
private boolean isHead(int position) {
return headCount!=&&position<headCount;
}
private boolean isFoot(int position) {
return footCount!=&&(position>=(getBodySize()+headCount));
}
@Override
public int getItemViewType(int position) {
if (isHead(position)) {
return HEAD_TYPE;
}else if (isFoot(position)) {
return FOOT_TYPE;
}else {
return BODY_TYPE;
}
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
switch (viewType) {
case HEAD_TYPE:
return new HeadViewHolder(mLayoutInflater.inflate(R.layout.trend_head,parent,false));
case BODY_TYPE:
return new BodyViewHolder(mLayoutInflater.inflate(R.layout.itemview_trend,parent,false));
case FOOT_TYPE:
return new FootViewHolder(mLayoutInflater.inflate(R.layout.trend_bottom,parent,false));
default:
return null;
}
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof HeadViewHolder) {
}else if (holder instanceof BodyViewHolder) {
((BodyViewHolder) holder).body.setText((CharSequence) listData.get(position-headCount));
}else if (holder instanceof FootViewHolder) {
}
}
@Override
public int getItemCount() {
return headCount+getBodySize()+footCount;
}
private static class HeadViewHolder extends RecyclerView.ViewHolder{
public HeadViewHolder(View itemView) {
super(itemView);
}
}
private static class BodyViewHolder extends RecyclerView.ViewHolder{
TextView body;
public BodyViewHolder(View itemView) {
super(itemView);
body= (TextView) itemView.findViewById(R.id.tv_body);
}
}
private static class FootViewHolder extends RecyclerView.ViewHolder {
public FootViewHolder(View itemView) {
super(itemView);
}
}
}