编写准备

1. 定义接口如下

package com.llt.bottomnavigationf;

public interface OnItemClickListener {
    //当前点击的索引值
    void onTap(int index);
}

1. 点击事件类
   public class Scaffold {
   public OnItemClickListener onItemClickListener;> 因为我是web前端开发人员用词可能不会特别准确,点击事件类就是 你需要传递数据的类里面的点击方法

在类中声明接口

package com.llt.bottomnavigationf;

import com.llt.bottomnavigationf.entity.AppBar;
import com.llt.bottomnavigationf.entity.Body;
import com.llt.bottomnavigationf.entity.BottomNavItem;
import com.llt.bottomnavigationf.entity.BottomNavigation;
import com.llt.bottomnavigationf.fraction.FractionUtil;
import com.llt.bottomnavigationf.util.LogUtil;
import ohos.aafwk.ability.AbilityForm;
import ohos.aafwk.ability.OnClickListener;
import ohos.aafwk.ability.ViewsStatus;
import ohos.aafwk.ability.fraction.FractionAbility;
import ohos.agp.components.*;
import ohos.agp.utils.Color;
import ohos.agp.utils.LayoutAlignment;

import java.util.ArrayList;
import java.util.List;

public class Scaffold  {
//声明接口
    public OnItemClickListener onItemClickListener;
 	//编写 自定义监听方法
    public void setOnItemClickListener(OnItemClickListener listener){
	//将实现接口传递给内部 的onItemClickListener 接口
            this.onItemClickListener = listener;
    }
    public Scaffold() {
		initBottom();//初始化
    }
    public void initBottom(){
        /**
         * scaffold 内的id
         */
        DirectionalLayout scaffold_bottom_tabMenu_component =(DirectionalLayout)
                parse.findComponentById(ResourceTable.Id_scaffold_bottom_tabMenu);
    //绑定点击事件 	
bottomNavBarClick(scaffold_bottom_tabMenu_component ,1);
    }

    /**
     * 按钮点击事件
     * @param item 当前按钮
     * @param index 当前激活索引值

     */
    public void bottomNavBarClick(Component item, int index,List<Component> tabList){
        //底部传递进来的数据
        List<BottomNavItem> bottomNavItems = bottomNavigationBar.getBottomNavItems();
        item.setClickedListener(component -> {
            //点击传递数据 这里是回调函数参数赋值
            onItemClickListener.onTap(index);
  
        });

    }
}

1. 调用

    Scaffold init = new Scaffold();
        init.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onTap(int index) {
                LogUtil.info("自定义监听", Integer.toString(index));
            }
        });