Android可折叠收缩伸展的Expandable分组RecyclerView:模型抽象和封装(二)

Android可折叠收缩伸展的Expandable分组RecyclerView:模型抽象和封装(二)

如今Android这种可收缩伸展的Expandable RecyclerView是如此常用,在附录1的基础上,我重新把模型进行了抽象和封装,设计了一套新的架构和简洁的使用方式支持这种功能。重点就是ExpandableItemAdapter类,可直接把RecyclerView的Adapter直接继承ExpandableItemAdapter,然后在建立数据模型时候,把具有“组”意义的数据添加子Item时候,调用addSubItem,这样该RecyclerView就具有伸缩和展开的功能。
每一个Item内部存储了一个isExpand值,isExpand值决定在ExpandableItemAdapter初始后每一组是否伸展和收缩。isExpand为true时候,展开,为false时候,收起。
以下是全部代码。
Item.java:
package app.zhangphil.exp;

import java.util.ArrayList;
import java.util.UUID;

public abstract class Item {
    /**
     * 上层用户可以把此id作为Item的标识。
     */
    public int id;

    public int position;

    public boolean isExpand = true;

    /**
     * 当添加子Item时候,需要把当前的uniqueId作为子Item的parentUniqueId记录。
     *
     * 注意:虽然是public属性,但上层用户不应该使用uniqueId和parentUniqueId寻找和比对Item。
     * uniqueId和parentUniqueId仅用来处理底层的数据逻辑。
     */
    public String parentUniqueId = null;
    public final String uniqueId = UUID.randomUUID().toString();

    private ArrayList<Item> items = new ArrayList<>();

    public abstract int getType();

    /**
     * 添加该Item的子Item
     *
     * @param item
     */
    public void addSubItem(Item item) {
        item.parentUniqueId = uniqueId;
        items.add(item);
    }

    public void clearSubItems(){
        items.clear();
    }

    public ArrayList<Item> getSubItems() {
        return items;
    }
}
该Item类是RecyclerView装载的条目的数据抽象模型,开发者的数据对象要继承自该Item,并重写返回类型。addSubItem将(递归)添加二级(子)Item。

ItemVH.java:
package app.zhangphil.exp;

import android.support.v7.widget.RecyclerView;
import android.view.View;

public abstract class ItemVH extends RecyclerView.ViewHolder {

    public ItemVH(View itemView) {
        super(itemView);
    }

    public abstract int getType();
}
ItemVH继承自RecyclerView.ViewHolder,本质是一个ViewHolder。

ItemAdapter.java:

package app.zhangphil.exp;

import android.support.v7.widget.RecyclerView;
import java.util.ArrayList;

public abstract class ItemAdapter extends RecyclerView.Adapter<ItemVH> {
    private ArrayList<Item> mItems;

    public ItemAdapter() {
        mItems = new ArrayList<>();
    }

    @Override
    public int getItemCount() {
        return mItems.size();
    }

    @Override
    public int getItemViewType(int position) {
        return mItems.get(position).getType();
    }

    public Item getItem(int pos) {
        return mItems.get(pos);
    }

    public void addItem(Item item) {
        mItems.add(item);
    }

    public void addAll(ArrayList<Item> lists) {
        mItems.addAll(lists);
    }

    public ArrayList<Item> getAllItem() {
        return mItems;
    }

    /**
     * 清空所有Item。
     */
    public void clear() {
        mItems.clear();
    }

    /**
     * 寻找具有特定type和id的Item。
     *
     * @param type
     * @param id
     * @return
     */
    public Item getItem(int type, int id) {
        Item mItem = null;
        for (int i = 0; i < mItems.size(); i++) {
            Item item = mItems.get(i);
            if (item.getType() == type && item.id == id) {
                mItem = item;
            }
        }

        return mItem;
    }
}
ItemAdapter继承自RecyclerView.Adapter,做了简单的初始化和抽象。

最重要的是ExpandableItemAdapter,ExpandableItemAdapter实现了全部的展开和折叠Item的功能。ExpandableItemAdapter是可以直接拿来作为RecyclerView的Adapter使用,开发者可以直接继承ExpandableItemAdapter以实现RecyclerView分组的折叠和展开功能。
ExpandableItemAdapter.java:
package app.zhangphil.exp;

import android.support.annotation.NonNull;
import android.text.TextUtils;
import android.view.ViewGroup;

import java.util.Iterator;

public abstract class ExpandableItemAdapter extends ItemAdapter {

    @NonNull
    @Override
    public abstract ItemVH onCreateViewHolder(@NonNull ViewGroup parent, int viewType);

    @Override
    public abstract void onBindViewHolder(@NonNull ItemVH holder, int position);

    /**
     * 展开Item
     *
     * @param item
     */
    public void expand(Item item) {
        int pos = -1;

        for (int i = 0; i < getItemCount(); i++) {
            Item it = getItem(i);
            if (TextUtils.equals(it.uniqueId, item.uniqueId)) {
                pos = i;
            }
        }

        getAllItem().set(pos, item);

        Iterator<Item> iterator = getAllItem().iterator();
        while (iterator.hasNext()) {
            Item it = iterator.next();
            if (TextUtils.equals(it.parentUniqueId, item.uniqueId)) {
                iterator.remove();
            }
        }

        if (item.getSubItems().size() > 0) {
            getAllItem().addAll(pos + 1, item.getSubItems());
        }

        item.isExpand = true;

        if (mExpandableToggleListener != null) {
            mExpandableToggleListener.onExpand(item);
        }
    }

    /**
     * 收起Item
     *
     * @param item
     */
    public void collapse(Item item) {
        Iterator<Item> iterator = getAllItem().iterator();
        while (iterator.hasNext()) {
            Item it = iterator.next();
            if (TextUtils.equals(it.parentUniqueId, item.uniqueId)) {
                iterator.remove();
            }
        }

        item.isExpand = false;

        if (mExpandableToggleListener != null) {
            mExpandableToggleListener.onCollapse(item);
        }
    }

    /**
     * 更新Item
     *
     * @param item
     */
    public void setItem(Item item) {
        int pos = -1;
        for (int i = 0; i < getItemCount(); i++) {
            Item it = getItem(i);
            if (TextUtils.equals(it.uniqueId, item.uniqueId)) {
                pos = i;
            }
        }

        getAllItem().set(pos, item);

        Iterator<Item> iterator = getAllItem().iterator();
        while (iterator.hasNext()) {
            Item it = iterator.next();
            if (TextUtils.equals(it.parentUniqueId, item.uniqueId)) {
                iterator.remove();
            }
        }

        if (item.isExpand) {
            if (item.getSubItems().size() > 0) {
                getAllItem().addAll(pos + 1, item.getSubItems());
            }
        } else {

        }
    }

    /**
     * 添加一个Item,该Item可以是一个普通的Item,也可以是一个包含子Item的item。
     *
     * @param item
     */
    @Override
    public void addItem(Item item) {
        super.addItem(item);

        if (item.isExpand) {
            for (int i = 0; i < item.getSubItems().size(); i++) {
                super.addItem(item.getSubItems().get(i));
            }
        } else {

        }
    }

    public interface ExpandableToggleListener {
        public void onExpand(Item item);

        public void onCollapse(Item item);
    }

    private ExpandableToggleListener mExpandableToggleListener = null;

    public void setExpandableToggleListener(ExpandableToggleListener listener) {
        this.mExpandableToggleListener = listener;
    }

    public void toggle(Item item) {
        item.isExpand = !item.isExpand;

        if (item.isExpand) {
            expand(item);
        } else {
            collapse(item);
        }
    }
}



现给出一个使用例子:
package app.zhangphil.exp;

import android.graphics.Color;
import android.os.Handler;
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 android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private final int TYPE_GROUP = 0xfa01;
    private final int TYPE_CHILD = 0xfa02;

    private RecyclerViewAdapter mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        RecyclerView recyclerView = findViewById(R.id.recycler_view);

        LinearLayoutManager layoutManage = new LinearLayoutManager(this);
        layoutManage.setOrientation(LinearLayoutManager.VERTICAL);

        recyclerView.setLayoutManager(layoutManage);

        mAdapter = new RecyclerViewAdapter();
        recyclerView.setAdapter(mAdapter);

        String[] groupNames = {"A", "B", "C", "D", "E", "F", "G"};
        for (int i = 0; i < groupNames.length; i++) {
            Group group = new Group();
            group.id = i;
            if (i == 0)
                group.isExpand = true;
            else {
                group.isExpand = false;
            }
            group.title = groupNames[i];

            int count = (int) (Math.random() * 10) % 5 + 1;
            for (int j = 0; j < count; j++) {
                Child child = new Child();
                child.position = j;
                child.group = group;

                group.addSubItem(child);
            }

            mAdapter.addItem(group);
        }

        mAdapter.setExpandableToggleListener(new ExpandableItemAdapter.ExpandableToggleListener() {
            @Override
            public void onExpand(Item item) {
                Toast.makeText(getApplicationContext(), ((Group) item).title + " 展开", Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onCollapse(Item item) {
                Toast.makeText(getApplicationContext(), ((Group) item).title + " 收起", Toast.LENGTH_SHORT).show();
            }
        });

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                //更新第0组
                Group mGroup = (Group) mAdapter.getItem(0);
                mGroup.clearSubItems();

                mGroup.title = "zhangphil";

                Child child = new Child();
                child.group = mGroup;
                child.position = 2018;

                mGroup.addSubItem(child);

                mAdapter.setItem(mGroup);

                mAdapter.notifyDataSetChanged();
            }
        }, 3000);
    }

    public class RecyclerViewAdapter extends ExpandableItemAdapter {
        @Override
        public ItemVH onCreateViewHolder(ViewGroup parent, int viewType) {
            View view;
            ItemVH itemVH = null;
            switch (viewType) {
                case TYPE_GROUP:
                    view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
                    itemVH = new GroupVH(view);
                    break;

                case TYPE_CHILD:
                    view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_2, parent, false);
                    itemVH = new ChildVH(view);
                    break;
            }

            return itemVH;
        }

        @Override
        public void onBindViewHolder(ItemVH holder, int position) {
            Item item = getItem(position);
            switch (getItemViewType(position)) {
                case TYPE_GROUP:
                    final Group g = (Group) item;
                    GroupVH groupVH = (GroupVH) holder;
                    groupVH.text.setText(g.title);

                    groupVH.itemView.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            toggle(g);
                            notifyDataSetChanged();
                        }
                    });
                    break;

                case TYPE_CHILD:
                    Child c = (Child) item;
                    ChildVH childVH = (ChildVH) holder;
                    childVH.text1.setText(c.group.title);
                    childVH.text2.setText(c.position + "");
                    break;
            }
        }
    }

    private class Group extends Item {
        public String title;

        @Override
        public int getType() {
            return TYPE_GROUP;
        }
    }

    private class Child extends Item {
        public Group group;

        @Override
        public int getType() {
            return TYPE_CHILD;
        }
    }

    private class GroupVH extends ItemVH {
        public TextView text;

        public GroupVH(View itemView) {
            super(itemView);
            text = itemView.findViewById(android.R.id.text1);
            text.setBackgroundColor(Color.RED);
        }

        @Override
        public int getType() {
            return TYPE_GROUP;
        }
    }

    private class ChildVH extends ItemVH {
        public TextView text1;
        public TextView text2;

        public ChildVH(View itemView) {
            super(itemView);
            text1 = itemView.findViewById(android.R.id.text1);
            text2 = itemView.findViewById(android.R.id.text2);
            text1.setTextColor(Color.LTGRAY);
            text2.setTextColor(Color.BLUE);
        }

        @Override
        public int getType() {
            return TYPE_CHILD;
        }
    }
}

初始后,由于第0个Group的isExpand为true,其他Group均为fasle,所以展开第0组,折叠其他组:

Android可折叠收缩伸展的Expandable分组RecyclerView:模型抽象和封装(二)



过了三秒,更新了第0组全部数据。
Android可折叠收缩伸展的Expandable分组RecyclerView:模型抽象和封装(二)


伸展或折叠其他组:

Android可折叠收缩伸展的Expandable分组RecyclerView:模型抽象和封装(二)


项目代码和库已经上传到github上:https://github.com/zhangphil/recyclerview


附录:
1,《Android可收缩伸展的Expandable分组RecyclerView》链接:https://blog.csdn.net/zhangphil/article/details/79814332 

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