Android RecyclerView GridLayout

RecycerView GridLayoutManager 网格布局默认展示一行 正常的GridLayoutManager 布局每行展示的是估计数量的子条目 但是有些需求需要每行展示不固定数量的子条目这个时候就需要用到了SpanSizeLookup 处理每行展示子条目的数量

SpanSizeLookup 的getSpanSize(position)方法 返回置顶Item占用屏幕的 spanCount:GridLayoutManager的每行份数

Demo

package com.wu.material.activity.rv

import android.content.Context
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import androidx.databinding.DataBindingUtil
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.wu.material.R
import com.wu.material.databinding.ActivityComplicatedRecyclerviewBinding


/**
 * @author wkq
 *
 * @date 2022年03月01日 9:19
 *
 *@des
 *
 */

class ComplicatedRecyclerViewActivity : AppCompatActivity() {
    var binding: ActivityComplicatedRecyclerviewBinding? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = DataBindingUtil.setContentView<ActivityComplicatedRecyclerviewBinding>(this, R.layout.activity_complicated_recyclerview)
        initView()
    }

    private fun initView() {
        var mAdapter = RecyclerViewActivity.DemoAdapter(this)
        //一行分多少份
        var gridLayoutManager = GridLayoutManager(this, 120)
        binding!!.rvContent.layoutManager = gridLayoutManager

        gridLayoutManager.spanSizeLookup = object : GridLayoutManager.SpanSizeLookup() {
            override fun getSpanSize(position: Int): Int {
                // 返回的是 表示每个条目占用几几份  屏幕分了120份
                when (position) {
                    0 -> {
                        return 120
                    }
                    1 -> {
                        return 60
                    }
                    2 -> {
                        return 60
                    }
                    3 -> {
                        return 40
                    }
                    4 -> {
                        return 40
                    }
                    5 -> {
                        return 40
                    }
                    6 -> {
                        return 120
                    }
                    else -> {
                        return 30
                    }

                }
            }
        }

        //设置 Adapter
        binding!!.rvContent.adapter = mAdapter
        var listData = ArrayList<String>()
        listData.add("Android新控件")
        listData.add("循环效果2:循环")
        listData.add("Android")
        listData.add("MotionLayout")
        listData.add("Banner")
        listData.add("Banner")
        listData.add("Banner")
        listData.add("Banner")
        listData.add("Banner")
        listData.add("Banner")
        listData.add("Banner")
        listData.add("Banner")
        listData.add("Banner")
        listData.add("Banner")
        listData.add("Banner")
        listData.add("循环效果2")
        listData.add("Android新控件之MotionLayout实现Banner循环效果2:循环")
        //刷新数据
        mAdapter.addItems(listData)
    }


    // 自定义Adapter
    class DemoAdapter(mContext: Context) : RecyclerView.Adapter<DemoViewHolder>() {
        var mContext: Context? = null
        var listData = ArrayList<String>()

        init {
            this.mContext = mContext
        }

        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DemoViewHolder {
            var view = LayoutInflater.from(mContext).inflate(R.layout.item_demo, parent, false)
            var viewHolder = DemoViewHolder(view)
            return viewHolder
        }

        override fun onBindViewHolder(holder: DemoViewHolder, position: Int) {
            var mHolder = holder
            mHolder.getTextView().text = listData.get(position)
        }

        override fun getItemCount(): Int {
            return listData.size
        }

        fun addItems(items: ArrayList<String>) {
            listData.addAll(items)
            //刷新数据
            notifyDataSetChanged()
//            notifyItemChanged(2)
        }

    }

    // 自定义Holder
    class DemoViewHolder(view: View) : RecyclerView.ViewHolder(view) {
        var rootView: View? = null

        init {
            rootView = view
        }

        fun getTextView(): TextView {
            var tvContent = rootView!!.findViewById<TextView>(R.id.tv_content)
            return tvContent
        }
    }


}

总结:

GridLayoutManager网格布局管理器 实现一行展示多个条目,本章解释了GridLayoutManager的简单源码实现表格布局的大概调用,下一章展示复杂的表格布局即展示不顾地条目数的表格布局

GridLayoutManager的 spanSizeLookup 监听返回每个Item占用 spanCount 的份数用于处理每行展示不同的条目数

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参考文献

1.RecyclerView Google Developer概览

2.Demo源码地址