Android可收缩伸展的Expandable分组RecyclerView
Android上的可收缩伸展的Expandable RecyclerView第三方开源项目很多，但是在自己的项目引用了这些github上的类似项目后，发现问题和Bug很多，不稳定，无奈之下，自己在RecyclerView基础上写了一个相对稳定、可以收缩伸展Expandable分组RecyclerView。
代码：
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.Iterator;
public class MainActivity extends AppCompatActivity {
private RecyclerViewAdapter mAdapter;
private final int GROUP = 0xf01;
private final int CHILD = 0xf02;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
RecyclerView mRecyclerView = findViewById(R.id.recycler_view);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
mRecyclerView.setLayoutManager(layoutManager);
ArrayList<Item> mItems = new ArrayList<>();
mAdapter = new RecyclerViewAdapter(mItems);
mRecyclerView.setAdapter(mAdapter);
String[] groups = {"A", "B", "C", "D", "E", "F"};
for (int i = 0; i < groups.length; i++) {
GroupItem groupItem = new GroupItem();
groupItem.id = i;
groupItem.title = groups[i];
int count = (int) (Math.random() * 10) % 5 + 1;
for (int j = 0; j < count; j++) {
ChildItem childItem = new ChildItem();
childItem.id = j;
childItem.group = groupItem;
groupItem.addChild(childItem);
}
mAdapter.addGroup(groupItem);
}
mAdapter.expand(0);
}
public class RecyclerViewAdapter extends RecyclerView.Adapter<ItemVH> {
private ArrayList<Item> items;
public RecyclerViewAdapter(ArrayList<Item> items) {
this.items = items;
}
public void addGroup(GroupItem groupItem) {
items.add(groupItem);
}
@Override
public ItemVH onCreateViewHolder(ViewGroup parent, int viewType) {
View view;
ItemVH itemVH = null;
switch (viewType) {
case GROUP:
view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
itemVH = new GroupVH(view);
break;
case CHILD:
view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
itemVH = new ChildVH(view);
break;
}
return itemVH;
}
@Override
public void onBindViewHolder(ItemVH holder, final int position) {
int viewType = getItemViewType(position);
Item item = items.get(position);
switch (viewType) {
case GROUP:
final GroupItem groupItem = (GroupItem) item;
GroupVH groupVH = (GroupVH) holder;
groupVH.text1.setText(groupItem.title);
groupVH.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
action(groupItem, position);
}
});
break;
case CHILD:
ChildItem childItem = (ChildItem) item;
ChildVH childVH = (ChildVH) holder;
childVH.text1.setText(childItem.id + "");
break;
}
}
@Override
public int getItemCount() {
return items.size();
}
@Override
public int getItemViewType(int position) {
return items.get(position).type();
}
public void expand(int groupOrder) {
for (int i = 0; i < items.size(); i++) {
Item item = items.get(i);
if (item.type() == GROUP) {
GroupItem groupItem = (GroupItem) item;
if (groupItem.id == groupOrder) {
items.addAll(i + 1, groupItem.children);
groupItem.isExpand = true;
}
}
}
mAdapter.notifyDataSetChanged();
}
private void action(GroupItem groupItem, int position) {
groupItem.isExpand = !groupItem.isExpand;
if (groupItem.isExpand) {
items.addAll(position + 1, groupItem.children);
} else {
Iterator<Item> iterator = items.iterator();
while (iterator.hasNext()) {
Item it = iterator.next();
if (it.type() == CHILD) {
ChildItem cid = (ChildItem) it;
if (cid.group.id == groupItem.id)
iterator.remove();
}
}
}
mAdapter.notifyDataSetChanged();
}
}
private abstract class Item {
public int id;
public abstract int type();
}
private abstract class ItemVH extends RecyclerView.ViewHolder {
public ItemVH(View itemView) {
super(itemView);
}
public abstract int type();
}
private class ChildItem extends Item {
public GroupItem group;
@Override
public int type() {
return CHILD;
}
}
private class GroupItem extends Item {
public String title;
public boolean isExpand = false;
public ArrayList<ChildItem> children;
public GroupItem() {
children = new ArrayList<>();
}
@Override
public int type() {
return GROUP;
}
public void addChild(ChildItem childItem) {
children.add(childItem);
}
}
private class ChildVH extends ItemVH {
public TextView text1;
public ChildVH(View itemView) {
super(itemView);
text1 = itemView.findViewById(android.R.id.text1);
text1.setBackgroundColor(Color.LTGRAY);
}
@Override
public int type() {
return CHILD;
}
}
private class GroupVH extends ItemVH {
private TextView text1;
public GroupVH(View itemView) {
super(itemView);
text1 = itemView.findViewById(android.R.id.text1);
text1.setTextColor(Color.WHITE);
itemView.setBackgroundColor(Color.RED);
}
@Override
public int type() {
return GROUP;
}
}
}
运行结果：