Android中RecyclerView实现多级列表展示效果

dependencies {
	implementation 'com.android.support:recyclerview-v7:+'
}

<?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".mainactivity">
    <android.support.v7.widget.recyclerview
        android:id="@+id/recyclerview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</linearlayout>

<?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">
    <imageview
        android:id="@+id/iv_arrow"
        android:visibility="gone"
        android:layout_width="24dp"
        android:layout_height="24dp"
        android:layout_marginend="8dp"
         /><!--可添加自己所用展开、收起图片-->
    <textview
        android:id="@+id/tv_item_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textsize="16sp"
        android:textcolor="@android:color/black" />
</linearlayout>

package com.example.recycler;
import java.util.arraylist;
import java.util.list;
// treenode.java
public class treenode {
    private string id;
    private string name;
    private int level; // 层级，0开始
    private boolean isexpanded; // 是否展开
    private treenode parent; // 父节点
    private list<treenode> children; // 子节点
    private object data; // 其他数据
    public treenode(string id, string name,int level) {
        this.id = id;
        this.name = name;
        this.children = new arraylist<>();
        this.isexpanded = false;
        this.level = level;
    }
    // getters and setters
    public string getid() { return id; }
    public void setid(string id) { this.id = id; }
    public string getname() { return name; }
    public void setname(string name) { this.name = name; }
    public int getlevel() { return level; }
    public void setlevel(int level) { this.level = level; }
    public boolean isexpanded() { return isexpanded; }
    public void setexpanded(boolean expanded) { isexpanded = expanded; }
    public treenode getparent() { return parent; }
    public void setparent(treenode parent) { this.parent = parent; }
    public list<treenode> getchildren() { return children; }
    public void setchildren(list<treenode> children) { this.children = children; }
    public object getdata() { return data; }
    public void setdata(object data) { this.data = data; }
    // 添加子节点
    public void addchild(treenode child) {
        child.setparent(this);
        child.setlevel(this.level + 1);
        children.add(child);
    }
    // 判断是否有子节点
    public boolean haschildren() {
        return children != null && !children.isempty();
    }
}

package com.example.recycler;
import android.support.annotation.nonnull;
import android.support.v7.widget.recyclerview;
import android.view.layoutinflater;
import android.view.view;
import android.view.viewgroup;
import android.widget.imageview;
import android.widget.textview;
import java.util.arraylist;
import java.util.list;
public class multileveladapter extends recyclerview.adapter<multileveladapter.viewholder> {
    private list<treenode> displaynodes; // 实际显示的数据
    private list<treenode> allnodes; // 所有数据
    private onitemclicklistener listener;
    public multileveladapter(list<treenode> data) {
        this.allnodes = data;
        this.displaynodes = getdisplaynodes(data);
    }
    // 获取要显示的节点（展开的节点）
    private list<treenode> getdisplaynodes(list<treenode> nodes) {
        list<treenode> result = new arraylist<>();
        for (treenode node : nodes) {
            result.add(node);
            if (node.isexpanded() && node.haschildren()) {
                result.addall(getdisplaynodes(node.getchildren()));
            }
        }
        return result;
    }
    @nonnull
    @override
    public viewholder oncreateviewholder(@nonnull viewgroup parent, int viewtype) {
        view view = layoutinflater.from(parent.getcontext())
                .inflate(r.layout.item_multi_level, parent, false);
        return new viewholder(view);
    }
    @override
    public void onbindviewholder(@nonnull final viewholder holder, int position) {
        treenode node = displaynodes.get(position);
        // 设置缩进
        int paddingleft = node.getlevel() * 50; // 每级缩进50dp
        system.out.println("缩进:::"+paddingleft);
        holder.itemview.setpadding(paddingleft, 0, 0, 0);
        // 设置文本
        holder.textview.settext(node.getname());
        // 设置箭头图标
        if (node.haschildren()) {
            holder.arrowicon.setvisibility(view.visible);
        } else {
            holder.arrowicon.setvisibility(view.gone);
        }
		if (node.isexpanded())
			//展开图片设置
			holder.arrowicon.setbackground(你的图片)
		else
			//收起图片设置
			holder.arrowicon.setbackground(你的图片)
        // 点击事件
        holder.itemview.setonclicklistener(new view.onclicklistener() {
            @override
            public void onclick(view v) {
                int adapterposition = holder.getadapterposition();
                if (adapterposition != recyclerview.no_position) {
                    treenode clickednode = displaynodes.get(adapterposition);
                    if (clickednode.haschildren()) {
                        // 有子节点：切换展开/收起状态
                        int removecount = 0;
                        if (clickednode.isexpanded()) {
                            removecount = countallchildren(clickednode);
                            clearallchildexpand(clickednode);
                        }
                        clickednode.setexpanded(!clickednode.isexpanded());
                        refreshdisplaynodes();
						//int a = 收起图片
                        if (clickednode.isexpanded()) {
							a = 展开图片
                            notifyitemrangeinserted(adapterposition + 1, clickednode.getchildren().size());
                        }else if (!clickednode.isexpanded()&&removecount!=0){
                            notifyitemrangeremoved(adapterposition + 1, removecount);
                        }
						holder.arrowicon.setbackground(a)
                    } else {
                        // 没有子节点：触发点击事件
                        if (listener != null) {
                            listener.onitemclick(clickednode);
                        }
                    }
                }
            }
        });
        // 长按事件（可选）
        holder.itemview.setonlongclicklistener(new view.onlongclicklistener() {
            @override
            public boolean onlongclick(view v) {
                if (listener != null) {
                    return listener.onitemlongclick(displaynodes.get(holder.getadapterposition()));
                }
                return false;
            }
        });
    }
    // 计算节点的所有子节点数量（包括子节点的子节点）
    private int countallchildren(treenode node) {
        int count = 0;
        if (node.haschildren() && node.isexpanded()) {
            for (treenode child : node.getchildren()) {
                count++;
                if (child.isexpanded()) {
                    count += countallchildren(child);
                }
            }
        }
        return count;
    }
    private void clearallchildexpand(treenode node) {
        if (node.haschildren()) {
            for (treenode child : node.getchildren()) {
                child.setexpanded(false);
                clearallchildexpand(child);
            }
        }
    }
    // 刷新显示的数据
    private void refreshdisplaynodes() {
        displaynodes = getdisplaynodes(allnodes);
    }
    @override
    public int getitemcount() {
        return displaynodes.size();
    }
    // 设置数据
    public void setdata(list<treenode> data) {
        this.allnodes = data;
        refreshdisplaynodes();
        notifydatasetchanged();
    }
    // 展开/收起所有节点
    public void expandall() {
        setexpandedforall(allnodes, true);
        refreshdisplaynodes();
        notifydatasetchanged();
    }
    public void collapseall() {
        setexpandedforall(allnodes, false);
        refreshdisplaynodes();
        notifydatasetchanged();
    }
    private void setexpandedforall(list<treenode> nodes, boolean expanded) {
        for (treenode node : nodes) {
            node.setexpanded(expanded);
            if (node.haschildren()) {
                setexpandedforall(node.getchildren(), expanded);
            }
        }
    }
    // viewholder
    static class viewholder extends recyclerview.viewholder {
        textview textview;
        imageview arrowicon;
        public viewholder(@nonnull view itemview) {
            super(itemview);
            textview = itemview.findviewbyid(r.id.tv_item_name);
            arrowicon = itemview.findviewbyid(r.id.iv_arrow);
        }
    }
    // 点击监听接口
    public interface onitemclicklistener {
        void onitemclick(treenode node);
        boolean onitemlongclick(treenode node);
    }
    public void setonitemclicklistener(onitemclicklistener listener) {
        this.listener = listener;
    }
}

package com.example.recycler;
import android.app.activity;
import android.os.bundle;
import android.support.v7.widget.linearlayoutmanager;
import android.support.v7.widget.recyclerview;
import android.util.log;
import android.widget.toast;
import java.util.arraylist;
import java.util.list;
// mainactivity.java
public class mainactivity extends activity {
    private recyclerview recyclerview;
    private multileveladapter adapter;
    @override
    protected void oncreate(bundle savedinstancestate) {
        super.oncreate(savedinstancestate);
        setcontentview(r.layout.activity_main);
        recyclerview = findviewbyid(r.id.recyclerview);
        recyclerview.setlayoutmanager(new linearlayoutmanager(this));
        // 创建测试数据
        list<treenode> data = createtestdata();
        adapter = new multileveladapter(data);
        recyclerview.setadapter(adapter);
        // 设置点击监听
        adapter.setonitemclicklistener(new multileveladapter.onitemclicklistener() {
            @override
            public void onitemclick(treenode node) {
                // 处理没有子节点的点击事件
                toast.maketext(mainactivity.this,
                        "点击了: " + node.getname(), toast.length_short).show();
                // 可以在这里处理业务逻辑
                handleleafclick(node);
            }
            @override
            public boolean onitemlongclick(treenode node) {
                // 长按事件
                showoptionsdialog(node);
                return true;
            }
        });
    }
    // 创建测试数据（支持无限层级）
    private list<treenode> createtestdata() {
        list<treenode> rootnodes = new arraylist<>();
        // 第1级
        for (int i = 1; i <= 3; i++) {
            treenode level1 = new treenode("1-" + i, "一级节点 " + i,0);
            level1.setlevel(0);
            // 第2级
            for (int j = 1; j <= 2; j++) {
                treenode level2 = new treenode("2-" + i + "-" + j, "二级节点 " + i + "-" + j,level1.getlevel());
                level1.addchild(level2);
                // 第3级
                for (int k = 1; k <= (i == 1 ? 3 : 0); k++) {
                    treenode level3 = new treenode("3-" + i + "-" + j + "-" + k,
                            "三级节点 " + i + "-" + j + "-" + k,level2.getlevel());
                    level2.addchild(level3);
                    // 第4级（演示无限层级）
                    if (i == 1 && j == 1) {
                        for (int l = 1; l <= 2; l++) {
                            treenode level4 = new treenode("4-" + i + "-" + j + "-" + k + "-" + l,
                                    "四级节点 " + i + "-" + j + "-" + k + "-" + l,level3.getlevel());
                            level3.addchild(level4);
                        }
                    }
                }
            }
            rootnodes.add(level1);
        }
        return rootnodes;
    }
    // 处理叶子节点点击
    private void handleleafclick(treenode node) {
        // 这里实现你的业务逻辑
        log.d("multilevel", "点击了叶子节点: " + node.getname());
    }
}