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Expand RecycleView 是单个RecycleView 来实现 ExpandableListView 的效果。好处是可以添加展开和搜索动画。 我们先看下效果:
展开的动画我用的是默认的,大家需要其他的动画的话,可以自己重写一下动画效果。这里主要看一下代码这么实现以及数据结构的整理。
这是我再做项目的时候,从服务器获取的数据。这个数据,我们再做的时候需要进一步处理。
1:处理数据,设置RecycleView 的布局
/**
* 整理数据
*/
private void initData() {
String json = new String(getAssertsFile(this, "data.json"));
Gson gson = new Gson();
myDataBean = gson.fromJson(json, MyDataBean.class);
categories = myDataBean.getData().getCategories();
if (subCategoriesBeansListShow.size() == 0) {
int size = categories.size();
//1:遍历大集合 categories (下面叫一级分类) SubCategories(下面叫二级分类)
for (int i = 0; i < size; i++) {
MyDataBean.DataBean.CategoriesBean categoriesBean = categories.get(i);
//2:创建二级分类对象,把一级分类的数据(name:aaaaaaa)放到二级分类对象中,并设置title为true
MyDataBean.DataBean.CategoriesBean.SubCategoriesBean subCategoriesBean = new MyDataBean.DataBean.CategoriesBean.SubCategoriesBean();
subCategoriesBean.setName(categoriesBean.getName());
subCategoriesBean.setTitle(true);
subCategoriesBean.setTitleOldListPos(i);
//3:创建二级分类对象,把一级分类的数据(introduce:bbbbbbb)放到二级分类对象中,并设置子View 的title为true
MyDataBean.DataBean.CategoriesBean.SubCategoriesBean subCategoriesBean2 = new MyDataBean.DataBean.CategoriesBean.SubCategoriesBean();
subCategoriesBean2.setName(categoriesBean.getIntroduce());
subCategoriesBean2.setChildTitle(true);
//4:把子View 的title 放到二级分类第一个
categoriesBean.getSub_categories().add(0, subCategoriesBean2);
//5:创建一个三级分类集合,放入我们创建的第一个二级分类对象
subCategoriesBeansListShow.add(subCategoriesBean);
}
rvExpand.setLayoutManager(new LinearLayoutManager(this));
homeCategoriesAdapter = new HomeCategoriesAdapter(this, categories, subCategoriesBeansListShow, this);
}
rvExpand.setAdapter(homeCategoriesAdapter);
//以下是对布局进行控制,3表示3个条目做为一行
final GridLayoutManager manager = new GridLayoutManager(this, 3);
manager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
//如果条目的 type 是 1 , 那么这个条目就占3个位置。也就是一行
if (homeCategoriesAdapter.getItemViewType(position) == 1) {
return 3;
//如果条目的 type 是 2 , 那么这个条目就占3个位置。也就是一行
} else if (homeCategoriesAdapter.getItemViewType(position) == 2) {
return 3;
} else {
return 1;
}
}
});
rvExpand.setLayoutManager(manager);
}
2:在Adapter里面根据 type 填充布局
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View itemView;
if (viewType == 1) {
itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_home_categories, parent, false);
return new ViewHolder(itemView);
} else if (viewType == 2 ) {
itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.categories_header, parent, false);
return new ViewHolderChildTitle(itemView);
} else {
itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_home_categories_gridview1, parent, false);
return new ViewHolder1(itemView);
}
}
3:如何优雅的为横向排列的 item 设置 间距。
//计算出横向排列的数据的大小 size (减1是减掉type = 2的情况)
int size = categories.get(titleOldListPos).getSub_categories().size()-1;
//每行是3个 就 %3 如果等于0 结果就是行数,
if (size % 3 == 0) {
pos = size / 3;
} else {
//如果不等于0 先将结果转为int 然后加一
pos = size / 3 + 1;
}
//postion - 3*行数 = 2+titleOldListPos 如果等式成立表示第一列
//postion - 3*行数 = 3+titleOldListPos 如果等式成立表示第二列
//postion - 3*行数 = 4+titleOldListPos 如果等式成立表示第三列
for (int i = 0; i <= pos; i++) {
if (position - 3 * i == titleOldListPos + 2) {
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
layoutParams.setMargins(30, 0, 10, 30);
itemSectionHolder.item_categories_relas.setLayoutParams(layoutParams);
} else if (position - 3 * i == titleOldListPos + 3) {
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
layoutParams.setMargins(10, 0, 10, 30);
itemSectionHolder.item_categories_relas.setLayoutParams(layoutParams);
} else if (position - 3 * i == titleOldListPos + 4) {
RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
layoutParams.setMargins(10, 0, 30, 30);
itemSectionHolder.item_categories_relas.setLayoutParams(layoutParams);
}
}
4:如何展开和收起布局
/**
* 展开某个item
*
* @param titleIndex 点击的title的position,还需要这个position在categories集合下面的角标时多少。这里算出来
*/
private void expand(int titleIndex, int categoriesPos) {
categoriesBeanListShow.addAll(categoriesPos + 1, categories.get(categoriesPos).getSub_categories());
curExpandChapterIndex = categoriesPos;
categories.get(categoriesPos).setExpand(true);
notifyItemRangeInserted(categoriesPos + 1, categories.get(categoriesPos).getSub_categories().size());
notifyItemRangeChanged(0, getItemCount(), "change_position");
}
/**
* 收起某个item
*
* @param titleIndex
*/
private void narrow(int titleIndex) {
if (titleIndex != -1) {
int removeStart = titleIndex + 1;
int removeCount = 0;
for (int i = removeStart; i < categoriesBeanListShow.size() && (getItemViewType(i) == 3 || getItemViewType(i) == 2); i++) {
removeCount++;
}
categoriesBeanListShow.removeAll(categories.get(titleIndex).getSub_categories());
categories.get(titleIndex).setExpand(false);
notifyItemRangeRemoved(removeStart, removeCount);
notifyItemRangeChanged(0, getItemCount(), "change_position");
}
}