项目需要做一个拖拽排序的需求(类似头条栏目排序),原先随意找了个三方库简单的处理了一下.但是随着项目的的迭代,越来越多的需求堆积下来,三方库不满足自己定制的一些需求.所以决定自己写一写这个效果
RecycleView 实现列表样式,ItemTouchHelper实现子条目的拖拽和侧滑删除.中间牵扯到指定条目禁止排序,禁止删除的功能.
1.1 主页面Activity代码
package com.wkq.dragrecycle
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import androidx.databinding.DataBindingUtil
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.LinearLayoutManager
import com.wkq.dragrecycle.databinding.ActivityMainBinding
class MainActivity : AppCompatActivity() {
var stringList = arrayListOf<String>("北京", "河北", "河南", "山东", "天津", "陕西",
"山西", "石家庄", "内蒙古", "黑龙江", "吉林", "新疆", "西藏", "安徽", "湖北"
)
private lateinit var mGridItemDecoration: GridSpaceItemDecoration
var binding: ActivityMainBinding? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView<ActivityMainBinding>(this, R.layout.activity_main)
initView()
}
private fun initView() {
//设置布局选择
binding!!.btChange.setOnClickListener {
when ( binding!!.rvContent.layoutManager) {
is GridLayoutManager -> {
binding!!.rvContent.layoutManager = LinearLayoutManager(this)
}
else -> {
binding!!.rvContent.layoutManager = GridLayoutManager(this, 4)
}
}
}
//默认网格布局
var mAdapter = DragAdapter(this)
mGridItemDecoration = GridSpaceItemDecoration(4)
binding!!.rvContent.addItemDecoration(mGridItemDecoration, 0)
binding!!.rvContent.layoutManager = GridLayoutManager(this, 4)
binding!!.rvContent.adapter = mAdapter
mAdapter.addItems(stringList)
//拖拽绑定的监听器
var callBack = DragItemCallback(mAdapter,true)
//拖拽触摸的帮助类
var itemTouchHelper = ItemTouchHelper(callBack)
//绑定Rv
itemTouchHelper.attachToRecyclerView(binding!!.rvContent)
mAdapter.setOnItemClickListener(object : DragAdapter.OnItemClickListener {
override fun onItemClick(position: Int) {
Toast.makeText(this@MainActivity, mAdapter.getItems().get(position), Toast.LENGTH_SHORT).show()
}
override fun onItemLongClick(holder: DragAdapterViewHolder) {
//长按开启拖拽
itemTouchHelper.startDrag(holder)
}
})
}
}
1.2 Adapter 代码实现(注意默认禁止操作Item的位置默认0)
package com.wkq.dragrecycle
import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.databinding.DataBindingUtil
import androidx.recyclerview.widget.RecyclerView
import com.wkq.dragrecycle.databinding.ItemDragBinding
/**
* @author wkq
*
* @date 2022年08月04日 13:05
*
* @des 拖拽的Adapter
*
* @param limitPosition 禁止操作的条目位置 默认第一个
*
*/
class DragAdapter(mContext: Context,limitPosition:Int=0) : RecyclerView.Adapter<DragAdapterViewHolder>() {
//上下文
var mContext=mContext
// 固定条目的位置
val limitPosition = limitPosition
//内容数据
private var contentList = ArrayList<String>()
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DragAdapterViewHolder {
var binding = DataBindingUtil.inflate<ItemDragBinding>(
LayoutInflater.from(mContext),
R.layout.item_drag,
parent,
false
)
var holder = DragAdapterViewHolder(binding.root)
holder.setDataBinding(binding)
return holder
}
override fun onBindViewHolder(holder: DragAdapterViewHolder, position: Int) {
var binding = holder.getBinding() as ItemDragBinding
if (limitPosition==position){
binding.tvContent.setBackgroundResource(R.drawable.shape_radius5_green2)
}else{
binding.tvContent.setBackgroundResource(R.drawable.shape_radius5_green)
}
binding.tvContent.text = contentList.get(position)
binding.tvContent.setOnClickListener {
mListener?.onItemClick(holder.adapterPosition)
}
binding.tvContent.setOnLongClickListener {
mListener?.onItemLongClick(holder)
return@setOnLongClickListener true
}
}
override fun getItemCount(): Int {
return contentList.size
}
fun addItems(items: ArrayList<String>) {
contentList.addAll(items)
}
fun addItems(item: String) {
contentList.add(item)
}
fun remove(item: String) {
contentList.remove(item)
notifyDataSetChanged()
}
fun getItems():ArrayList<String>{
return contentList
}
private var mListener: OnItemClickListener? = null
fun setOnItemClickListener(listener: OnItemClickListener) {
mListener = listener
}
interface OnItemClickListener {
fun onItemClick(position: Int)
fun onItemLongClick(holder: DragAdapterViewHolder)
}
}
package com.wkq.dragrecycle
import android.graphics.drawable.GradientDrawable
import android.util.Log
import androidx.core.content.ContextCompat
import androidx.core.view.ViewCompat
import androidx.recyclerview.widget.GridLayoutManager
import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import java.util.*
/**
* @author wkq
*
* @date 2022年08月04日 13:27
*
*@des 拖拽的接口回调
*
*@param isSwipe 是否支持侧滑 默认支持
*
*/
class DragItemCallback(adapter: DragAdapter, isSwipe: Boolean = true) : ItemTouchHelper.Callback() {
private var mAdapter = adapter
private var mData = adapter.getItems()
private var isSwipe = isSwipe
// 这个方法用于让RecyclerView拦截向上滑动，向下滑动，想左滑动
// makeMovementFlags(dragFlags, swipeFlags); dragFlags显示项目支持拖动的方向 swipe标记物品可以滑动的方向 0 表示禁止
// 网格布局:上下左右
// 线性布局:上下/左右
override fun getMovementFlags(
recyclerView: RecyclerView,
viewHolder: RecyclerView.ViewHolder
): Int {
//拖动标记 0 表示禁止
var dragFlags = 0
//侧滑标记
var swipeFlags = 0
var layoytManager = recyclerView.layoutManager
if (layoytManager is GridLayoutManager) {
//网格布局 默认禁止侧滑
if (viewHolder.adapterPosition != mAdapter.limitPosition) {
dragFlags =ItemTouchHelper.LEFT or ItemTouchHelper.UP or ItemTouchHelper.RIGHT or ItemTouchHelper.DOWN
}
return makeMovementFlags(dragFlags, swipeFlags)
} else if (layoytManager is LinearLayoutManager) {
//处理 禁止滑动模块得逻辑 禁止移动得模块 禁止左右滑动
if (viewHolder.adapterPosition != mAdapter.limitPosition) {
dragFlags = ItemTouchHelper.UP or ItemTouchHelper.DOWN
swipeFlags = ItemTouchHelper.START or ItemTouchHelper.END
}
return makeMovementFlags(dragFlags, swipeFlags)
}
//默认 禁止滑动 禁止拖拽
return makeMovementFlags(dragFlags, swipeFlags)
}
/**
* 拖拽移动得回调
*/
override fun onMove(
recyclerView: RecyclerView,
viewHolder: RecyclerView.ViewHolder,
target: RecyclerView.ViewHolder
): Boolean {
// 起始位置
val fromPosition = viewHolder.adapterPosition
// 结束位置
val toPosition = target.adapterPosition
// 固定位置 处理笃定位置不要移动
if (fromPosition == mAdapter.limitPosition || toPosition == mAdapter.limitPosition) {
return false
}
// 根据滑动方向 交换数据 for 循环不包含 toPosition 1 替代2 2替代3 3 替代4
if (fromPosition < toPosition) {
// 含头不含尾
for (index in fromPosition until toPosition) {
//交换集合得位置
Collections.swap(mData, index, index + 1)
}
} else {
// 含头不含尾
for (index in fromPosition downTo toPosition + 1) {
Collections.swap(mData, index, index - 1)
}
}
// 刷新布局
mAdapter.notifyItemMoved(fromPosition, toPosition)
return true
}
/**
* 滑动结束得回调 滑动删除得逻辑
*/
override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
// direction 滑动的状态
//ItemTouchHelper.START表示向左滑动
// ItemTouchHelper.END 向右边滑动
val position = viewHolder.adapterPosition
if (position != mAdapter.limitPosition) {
//表示 禁止移动得布局
mData.removeAt(position)
mAdapter.notifyItemRemoved(position)
}
}
/**
* 选中会回调这里 处理选中布局的展示样式
*/
override fun onSelectedChanged(viewHolder: RecyclerView.ViewHolder?, actionState: Int) {
if (viewHolder == null) return
//空闲状态
if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
ViewCompat.animate(viewHolder!!.itemView).setDuration(100).scaleX(1.2F).scaleY(1.2F)
.start()
}
super.onSelectedChanged(viewHolder, actionState)
}
/**
* 滑动结束 清理选中得状态 恢复布局的样式
*/
override fun clearView(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder) {
// 恢复显示
// 这里不能用if判断，因为GridLayoutManager是LinearLayoutManager的子类，改用when，类型推导有区别
ViewCompat.animate(viewHolder.itemView).setDuration(100).scaleX(1F).scaleY(1F).start()
super.clearView(recyclerView, viewHolder)
}
/**
* 是否支持长按拖拽，默认true
* 因为我们外部监听了长安处理操作所以 这里需要禁用没改掉
*/
override fun isLongPressDragEnabled(): Boolean {
return false
}
/**
* 是否支持侧滑默认true(线性布局的时候外部可以传进来)
*/
override fun isItemViewSwipeEnabled(): Boolean {
return isSwipe
}
}
3.1 getMovementFlags():Int{} 实现此方法获取移动的标志,方法内部需要调用makeMovementFlags(dragFlags, swipeFlags)方法设置拖拽和滑动的标志
该标志定义每个状态下启用的移动方向
// 这个方法用于让RecyclerView拦截向上滑动，向下滑动，想左滑动
// makeMovementFlags(dragFlags, swipeFlags); dragFlags显示项目支持拖动的方向 swipe标记物品可以滑动的方向 0 表示禁止
// 网格布局:上下左右
// 线性布局:上下/左右
override fun getMovementFlags(
recyclerView: RecyclerView,
viewHolder: RecyclerView.ViewHolder
): Int {
//拖动标记 0 表示禁止
var dragFlags = 0
//侧滑标记
var swipeFlags = 0
var layoytManager = recyclerView.layoutManager
if (layoytManager is GridLayoutManager) {
//网格布局 默认禁止侧滑
if (viewHolder.adapterPosition != mAdapter.limitPosition) {
dragFlags =ItemTouchHelper.LEFT or ItemTouchHelper.UP or ItemTouchHelper.RIGHT or ItemTouchHelper.DOWN
}
return makeMovementFlags(dragFlags, swipeFlags)
} else if (layoytManager is LinearLayoutManager) {
//处理 禁止滑动模块得逻辑 禁止移动得模块 禁止左右滑动
if (viewHolder.adapterPosition != mAdapter.limitPosition) {
dragFlags = ItemTouchHelper.UP or ItemTouchHelper.DOWN
swipeFlags = ItemTouchHelper.START or ItemTouchHelper.END
}
return makeMovementFlags(dragFlags, swipeFlags)
}
//默认 禁止滑动 禁止拖拽
return makeMovementFlags(dragFlags, swipeFlags)
}
3.2 makeMovementFlags(dragFlags, swipeFlags)
创建移动标志的便捷方法,通过此方法创建移动的标志.dragflag显示项目可以拖动的方向,swipe标记物品可以滑动的方向。返回由给定拖动和滑动标志组成的整数。
//源码
/**
* Convenience method to create movement flags.
* <p>
* For instance, if you want to let your items be drag & dropped vertically and swiped
* left to be dismissed, you can call this method with:
* <code>makeMovementFlags(UP | DOWN, LEFT);</code>
*
* @param dragFlags The directions in which the item can be dragged.
* @param swipeFlags The directions in which the item can be swiped.
* @return Returns an integer composed of the given drag and swipe flags.
*/
public static int makeMovementFlags(int dragFlags, int swipeFlags) {
return makeFlag(ACTION_STATE_IDLE, swipeFlags | dragFlags)
| makeFlag(ACTION_STATE_SWIPE, swipeFlags)
| makeFlag(ACTION_STATE_DRAG, dragFlags);
}
3.3 override fun onMove( recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder,target: RecyclerView.ViewHolder): Boolean {}
Item拖动的项从其旧位置移动到新位置时调用onMove()方法,在这里我们可以处理移动数据的刷新(重新排序数据)
/**
* 拖拽移动得回调
*/
override fun onMove(
recyclerView: RecyclerView,
viewHolder: RecyclerView.ViewHolder,
target: RecyclerView.ViewHolder
): Boolean {
// 起始位置
val fromPosition = viewHolder.adapterPosition
// 结束位置
val toPosition = target.adapterPosition
// 固定位置 处理笃定位置不要移动
if (fromPosition == mAdapter.limitPosition || toPosition == mAdapter.limitPosition) {
return false
}
// 根据滑动方向 交换数据 for 循环不包含 toPosition 1 替代2 2替代3 3 替代4
if (fromPosition < toPosition) {
// 含头不含尾
for (index in fromPosition until toPosition) {
//交换集合得位置
Collections.swap(mData, index, index + 1)
}
} else {
// 含头不含尾
for (index in fromPosition downTo toPosition + 1) {
Collections.swap(mData, index, index - 1)
}
}
// 刷新布局
mAdapter.notifyItemMoved(fromPosition, toPosition)
return true
}
3.4 拖拽/滑动状态的处理
/**
* 选中会回调这里 处理选中布局的展示样式
*/
override fun onSelectedChanged(viewHolder: RecyclerView.ViewHolder?, actionState: Int) {
if (viewHolder == null) return
//空闲状态
if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
ViewCompat.animate(viewHolder!!.itemView).setDuration(100).scaleX(1.2F).scaleY(1.2F)
.start()
}
super.onSelectedChanged(viewHolder, actionState)
}
/**
* 滑动/拖拽结束 清理选中得状态 恢复布局的样式
*/
override fun clearView(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder) {
// 恢复显示
// 这里不能用if判断，因为GridLayoutManager是LinearLayoutManager的子类，改用when，类型推导有区别
ViewCompat.animate(viewHolder.itemView).setDuration(100).scaleX(1F).scaleY(1F).start()
super.clearView(recyclerView, viewHolder)
}
注意:
actionState表示Item的状态
-
ItemTouchHelper.ACTION_STATE_IDLE 空闲状态。
-
ItemTouchHelper.ACTION_STATE_SWIPE 滑动状态。
-
ItemTouchHelper.ACTION_STATE_DRAG 拖拽状态。
3.5 滑动/拖拽的开关
/**
* 是否支持长按拖拽，默认true
* 因为我们外部监听了长安处理操作所以 这里需要禁用没改掉
*/
override fun isLongPressDragEnabled(): Boolean {
return false
}
/**
* 是否支持侧滑默认true(线性布局的时候外部可以传进来)
*/
override fun isItemViewSwipeEnabled(): Boolean {
return isSwipe
}
ItemTouchHelper是一个实用系统类，用于向RecyclerView添加滑动解除和拖放支持.通过这个类通过ItemTouchHelper.Callback() 回调帮助开发者实现了拖拽和滑动的效果
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