Kotlin binding+RecyclerView实现支付宝首页更多 应用编辑界面

activity 主布局页面：

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:background="@drawable/bg_white"android:orientation="vertical"><RelativeLayoutandroid:id="@+id/title"android:layout_width="fill_parent"android:layout_height="48dp"android:background="@color/colorBase" ><TextViewandroid:layout_height="wrap_content"android:layout_width="wrap_content"android:text="@string/app_title"android:layout_marginLeft="20dp"android:layout_gravity="center_vertical"android:layout_centerInParent="true"android:layout_alignParentLeft="true"android:textSize="12sp"/><TextViewandroid:id="@+id/submit"android:textSize="20sp"android:textColor="@color/colorWhite"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginRight="5dp"android:layout_alignParentRight="true"android:layout_centerInParent="true"android:gravity="center_vertical"android:text="保存"/></RelativeLayout><LinearLayoutandroid:layout_width="match_parent"android:layout_height="wrap_content"android:gravity="center_vertical"android:padding="10dp"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="我的应用"android:textColor="#333333"android:textSize="16sp" /><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginLeft="5dp"android:text="(按住可拖动调整顺序)"android:textColor="#808080"android:textSize="13sp" /></LinearLayout><androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/recyclerViewExist"android:layout_width="match_parent"android:layout_height="wrap_content"android:paddingRight="10dp" /><Viewandroid:layout_width="match_parent"android:layout_height="4dp"android:background="@color/line_color"></View><HorizontalScrollViewandroid:id="@+id/horizonLScrollView"android:layout_width="match_parent"android:layout_height="35dp"android:scrollbarThumbHorizontal="@color/transparent"android:scrollbars="none"><RadioGroupandroid:id="@+id/rg_tab"android:layout_width="wrap_content"android:layout_height="match_parent"android:gravity="center_vertical"android:orientation="horizontal" /></HorizontalScrollView><Viewandroid:layout_width="match_parent"android:layout_height="1px"android:background="@color/line_color"></View><androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/recyclerViewAll"android:layout_width="match_parent"android:layout_height="0dp"android:layout_weight="1"android:paddingRight="10dp" /></LinearLayout>

activity 代码：

package com.daobo.wandimport android.annotation.SuppressLintimport android.content.Contextimport android.content.Intentimport androidx.appcompat.app.AppCompatActivityimport android.os.Bundleimport android.view.Viewimport kotlinx.android.synthetic.main.activity_main.*import android.view.View.OnClickListenerimport androidx.recyclerview.widget.GridLayoutManagerimport com.daobo.wand.ui.*import android.widget.RadioButtonimport android.util.TypedValueimport android.view.Gravityimport androidx.recyclerview.widget.RecyclerViewimport android.app.Activityimport android.os.Buildimport android.util.DisplayMetricsimport android.widget.Toastimport poundButtonimport androidx.annotation.RequiresApiimport androidx.core.content.ContextCompatimport com.daobo.wand.ui.adapter.FunctionAdapterimport com.daobo.wand.ui.adapter.FunctionBlockAdapterimport com.daobo.wand.ui.listener.DefaultItemCallbackimport com.daobo.wand.ui.listener.DefaultItemTouchHelperimport com.daobo.wand.ui.util.SFUtils/*** 主菜单页面* @author xiaolong.li* @time -02-14*/class MainActivity : AppCompatActivity(), OnClickListener {private var blockAdapter: FunctionBlockAdapter? = nullprivate var functionAdapter: FunctionAdapter? = nullprivate var gridManager: GridLayoutManager? = nullprivate var scrollTab = ArrayList<String>()private var itemWidth = 0private var lastRow = 0private var isMove = false//滑动状态private var scrollPosition = 0private var currentTab: String? = null//当前的标签private var tabWidth = 0//标签宽度private var allData: ArrayList<FunctionItem>? = nullprivate var selData: ArrayList<FunctionItem>? = nullprivate var sfUtils: SFUtils? = nullprivate val maxCount = 14private var isDrag = falseoverride fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_main)init()addListener()submit.setOnClickListener(this)}private fun init () {sfUtils = SFUtils(this)allData = sfUtils!!.getAllFunctionItems() //sfUtils!!.getAllFunctionWithState()selData = sfUtils!!.getSelectFunctionItem()blockAdapter = FunctionBlockAdapter(this, selData!!)recyclerViewExist.layoutManager = GridLayoutManager(this, 4)recyclerViewExist.adapter = blockAdapterrecyclerViewExist.addItemDecoration(SpaceItemDecoration(4, dip2px(this, 10.0F)))val callback = DefaultItemCallback(blockAdapter!!)val helper = DefaultItemTouchHelper(callback)helper.attachToRecyclerView(recyclerViewExist)gridManager = GridLayoutManager(this, 4)gridManager!!.spanSizeLookup = object : GridLayoutManager.SpanSizeLookup() {override fun getSpanSize(position: Int): Int {val fi = allData!![position]return if (fi.isTitle) 4 else 1}}functionAdapter = FunctionAdapter(this, allData!!)recyclerViewAll.layoutManager = gridManagerrecyclerViewAll.adapter = functionAdapterval spaceDecoration = SpaceItemDecoration(4, dip2px(this, 10.0F))recyclerViewAll.addItemDecoration(spaceDecoration)itemWidth = getAtyWidth(this) / 4 + dip2px(this, 2.0F)resetEditHeight(selData!!.size)initTab()}private fun initTab () {try {val tabs = sfUtils!!.getTabFunctionItems()if (tabs != null && tabs.isNotEmpty()) {currentTab = tabs[0].mNameval padding = dip2px(this, 10.0F)val size = tabs.sizefor (i in 0 until size) {val item = tabs[i]if (item.isTitle) {scrollTab.add(item.mName.toString())val rb = RadioButton(this)rb.setPadding(padding, 0, padding, 0)rb.buttonDrawable = nullrb.gravity = Gravity.CENTERrb.text = item.mNamerb.tag = item.subItemCountrb.setTextSize(PLEX_UNIT_SP, 14F)try {rb.setTextColor(ContextCompat.getColorStateList(this, R.color.colorGray))} catch (e: Exception) {e.printStackTrace()}rb.setCompoundDrawablesWithIntrinsicBounds(null, null, null,ContextCompat.getDrawable(this, R.drawable.bg_block_tab))rb.setOnCheckedChangeListener(onCheckedChangeListener)rg_tab.addView(rb)}}(rg_tab.getChildAt(0) as RadioButton).isChecked = true}} catch (e: Exception) {e.printStackTrace()}}private fun resetEditHeight(size: Int) {var size = sizetry {if (size == 0) {size = 1}var row = size / 4 + if (size % 4 > 0) 1 else 0if (row <= 0)row = 1if (lastRow != row) {lastRow = rowval params = recyclerViewExist.layoutParamsparams.height = itemWidth * rowrecyclerViewExist.layoutParams = params}} catch (e: Exception) {e.printStackTrace()}}private val onCheckedChangeListener =CompoundButton.OnCheckedChangeListener { buttonView, isChecked ->try {val position = buttonView.tag as Intval text = buttonView.text.toString()if (currentTab != text && isChecked) {currentTab = textmoveToPosition(position)}} catch (e: Exception) {e.printStackTrace()}}private fun moveToPosition(position: Int) {val first = gridManager!!.findFirstVisibleItemPosition()val end = gridManager!!.findLastVisibleItemPosition()if (first == -1 || end == -1)returnif (position <= first) {//移动到前面gridManager!!.scrollToPosition(position)} else if (position >= end) {//移动到后面isMove = truescrollPosition = positiongridManager!!.smoothScrollToPosition(recyclerViewAll, null, position)} else {//中间部分val n = position - gridManager!!.findFirstVisibleItemPosition()if (n > 0 && n < allData!!.size) {val top = gridManager!!.findViewByPosition(position)!!.toprecyclerViewAll.scrollBy(0, top)}}}private val onScrollListener = object : RecyclerView.OnScrollListener() {override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {super.onScrollStateChanged(recyclerView, newState)try {if (isMove && newState == RecyclerView.SCROLL_STATE_IDLE) {isMove = falseval view = gridManager!!.findViewByPosition(scrollPosition)if (view != null) {val top = view.toprecyclerView.scrollBy(0, top)}}isDrag = newState == RecyclerView.SCROLL_STATE_DRAGGING} catch (e: Exception) {e.printStackTrace()}}override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {super.onScrolled(recyclerView, dx, dy)if (isDrag) { //拖动过程中val position = gridManager!!.findFirstVisibleItemPosition()if (position > 0) {for (i in 0 until position + 1) {if (allData!![i].isTitle) {currentTab = allData!![i].mName}}scrollTab(currentTab!!)}}}}private fun scrollTab(newTab: String) {try {val position = scrollTab.indexOf(currentTab)val targetPosition = scrollTab.indexOf(newTab)currentTab = newTabif (targetPosition != -1) {val x = (targetPosition - position) * getTabWidth()val radioButton = rg_tab.getChildAt(targetPosition) as RadioButtonradioButton.setOnCheckedChangeListener(null)radioButton.isChecked = trueradioButton.setOnCheckedChangeListener(onCheckedChangeListener)horizonLScrollView.scrollBy(x, 0)}} catch (e: Exception) {e.printStackTrace()}}private fun getTabWidth(): Int {if (tabWidth == 0) {if (rg_tab != null && rg_tab.childCount !== 0) {tabWidth = rg_tab.width / rg_tab.childCount}}return tabWidth}private fun dip2px(context: Context, dpValue: Float): Int {val scale = context.resources.displayMetrics.densityreturn (dpValue * scale + 0.5f).toInt()}private fun getAtyWidth(context: Context): Int {return try {val mDm = DisplayMetrics()(context as Activity).windowManager.defaultDisplay.getMetrics(mDm)mDm.widthPixels} catch (e: Exception) {0}}private fun addListener() {functionAdapter!!.setOnItemAddListener(object : FunctionAdapter.OnItemAddListener {override fun add(item: FunctionItem): Boolean {if (selData != null && selData!!.size < maxCount) { // 更新选择列表，所有列表已在内部进行更新try {selData!!.add(item)resetEditHeight(selData!!.size)blockAdapter!!.notifyDataSetChanged()item.mIsSelect = truereturn true} catch (e: Exception) {e.printStackTrace()}return false} else {Toast.makeText(this@MainActivity, "选中的模块不能超过" + maxCount + "个",Toast.LENGTH_SHORT).show()return false}}})blockAdapter!!.setOnItemRemoveListener(object : FunctionBlockAdapter.OnItemRemoveListener {override fun remove(item: FunctionItem) {// 更新所有列表，选择列表已在内部进行更新try {if (item?.mName != null) {for (i in allData!!.indices) {val data = allData!![i]if (data?.mName != null) {if (item.mName.equals(data.mName)) {data.mIsSelect = falsebreak}}}functionAdapter!!.notifyDataSetChanged()}resetEditHeight(selData!!.size)} catch (e: Exception) {e.printStackTrace()}}})recyclerViewAll.addOnScrollListener(onScrollListener)}override fun onClick(v: View?) {//TODO("not implemented")// To change body of created functions use File | Settings | File Templates.var intent = Intent()when(v?.id) {R.id.submit ->{//点击了sfUtils!!.saveSelectFunctionItem(selData!!)sfUtils!!.saveAllFunctionWithState(allData!!)Toast.makeText(this@MainActivity, "保存成功！",Toast.LENGTH_SHORT).show()}}}}

自定义控件代码：SquareRelativeLayout

package com.daobo.wand.uiimport android.content.Contextimport android.util.AttributeSetimport android.view.Viewimport android.widget.RelativeLayoutclass SquareRelativeLayout : RelativeLayout {constructor (context: Context, attrs: AttributeSet, defStyle: Int) : super(context, attrs, defStyle)constructor (context: Context, attrs: AttributeSet) : super(context, attrs)constructor (context: Context) : super(context)override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {var widthMeasureSpec = widthMeasureSpecvar heightMeasureSpec = heightMeasureSpecsetMeasuredDimension(View.getDefaultSize(0, widthMeasureSpec),View.getDefaultSize(0, heightMeasureSpec))val childWidthSize = measuredWidthwidthMeasureSpec =View.MeasureSpec.makeMeasureSpec(childWidthSize, View.MeasureSpec.EXACTLY)heightMeasureSpec = widthMeasureSpecsuper.onMeasure(widthMeasureSpec, heightMeasureSpec)}}

SpaceItemDecoration类：

package com.daobo.wand.uiimport androidx.recyclerview.widget.RecyclerViewimport android.graphics.Canvasimport android.graphics.Rectimport android.view.Viewimport androidx.recyclerview.widget.RecyclerView.ItemDecorationclass SpaceItemDecoration (row: Int, space: Int) : ItemDecoration() {private var mRow = rowprivate val mSpace = spaceoverride fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {outRect.left = mSpaceoutRect.bottom = mSpace//if (parent.getChildAdapterPosition(view) % row == 0)//outRect.left = 0}override fun onDrawOver(c: Canvas, parent: RecyclerView, state: RecyclerView.State) {super.onDrawOver(c, parent, state)}}

bean 类：

package com.daobo.wand.uiclass TabItem(tabName : String, functionItems : ArrayList<FunctionItem>) {private var mTtabName = tabNameprivate var mFunctionItems: ArrayList<FunctionItem>? = functionItemsfun getTabName(): String {return mTtabName}fun setTabName(tabName: String) {this.mTtabName = tabName}fun getFunctionItems(): ArrayList<FunctionItem>? {return mFunctionItems}fun setFunctionItems(functionItems: ArrayList<FunctionItem>) {this.mFunctionItems = functionItems}}

package com.daobo.wand.uiclass FunctionItem {var mName: String? = nullvar mIsSelect = falsevar mImageUrl = ""var mBackground = ""var isTitle = falsevar subItemCount = 0constructor(name: String, isSelect: Boolean, imageUrl: String, background: String) {this.mName = namethis.mIsSelect = isSelectthis.mImageUrl = imageUrlthis.mBackground = background}constructor(name: String, isTitle: Boolean, subItemCount: Int) {this.mName = namethis.isTitle = isTitlethis.subItemCount = subItemCount}constructor(name: String, isTitle: Boolean) {this.mName = namethis.isTitle = isTitle}}

package com.daobo.wand.ui.viewbeanclass FuncItemViewBean {var Name : String ? = ""var BtnImgSrc : Int = 0var IvImgSrc : Int = 0}

item 布局xml: layout_function_text

<?xml version="1.0" encoding="utf-8"?><layout xmlns:android="/apk/res/android"><data><variable name="name" type="String"/></data><TextViewandroid:id="@+id/func_text"android:layout_width="match_parent"android:layout_height="wrap_content"android:background="@drawable/bg_white"android:drawableLeft="@drawable/item_block_left"android:gravity="center_vertical"android:paddingBottom="4dp"android:paddingTop="4dp"android:textColor="@color/black"android:textSize="18sp"android:text="@{name}"/></layout>

layout_function_item

<?xml version="1.0" encoding="utf-8"?><layout xmlns:android="/apk/res/android"><data><variable name="funcItem" type="com.daobo.wand.ui.viewbean.FuncItemViewBean"/></data><com.daobo.wand.ui.SquareRelativeLayoutandroid:id="@+id/item"android:layout_width="match_parent"android:layout_height="wrap_content"android:background="@drawable/bg_grid_press"><LinearLayoutandroid:id="@+id/layout"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_centerInParent="true"android:gravity="center"android:orientation="vertical"><ImageViewandroid:id="@+id/iv"android:layout_width="wrap_content"android:layout_height="wrap_content"android:background="@null"android:contentDescription="@string/app_name"android:scaleType="centerInside"android:src="@{funcItem.ivImgSrc}"/><TextViewandroid:id="@+id/text"android:layout_marginTop="2dp"android:lines="2"android:textSize="12sp"android:paddingLeft="5dp"android:paddingRight="5dp"android:gravity="center_horizontal"android:textColor="@color/black"android:layout_gravity="center_horizontal"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="@{funcItem.Name}"/></LinearLayout><ImageViewandroid:id="@+id/btn"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_alignParentRight="true"android:layout_alignParentTop="true"android:layout_marginRight="1dp"android:layout_marginTop="1dp"android:background="@null"android:contentDescription="@string/app_name"android:padding="4dp"android:scaleType="centerInside"android:src="@{funcItem.btnImgSrc}" /></com.daobo.wand.ui.SquareRelativeLayout></layout>

自定义 drawable xml

bg_block_tab:

<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="/apk/res/android"><item android:drawable="@drawable/item_block_tab_checked" android:state_checked="true" /><item android:drawable="@drawable/item_block_tab_unchecked" android:state_checked="false" /></selector>

bg_blue:

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="/apk/res/android" ><solid android:color="@color/titlecolor" /></shape>

bg_grid_press:

<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="/apk/res/android"><item android:state_pressed="true"><shape><solid android:color="#f5f5f5" /></shape></item><item android:state_pressed="false"><shape><solid android:color="#f4f4f4" /></shape></item></selector>

bg_white:

<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="/apk/res/android"><solid android:color="@color/colorWhite"/></shape>

适配器代码：

package com.daobo.wand.ui.adapterimport androidx.recyclerview.widget.RecyclerViewimport com.daobo.wand.ui.FunctionItemimport android.content.Contextimport android.view.ViewGroupimport android.view.LayoutInflaterimport androidx.databinding.DataBindingUtilimport androidx.databinding.ViewDataBindingimport androidx.recyclerview.widget.RecyclerView.Adapterimport com.daobo.wand.BRimport com.daobo.wand.Rimport com.daobo.wand.databinding.LayoutGridItemBindingimport com.daobo.wand.ui.viewbean.FuncItemViewBeanclass FunctionAdapter : Adapter<RecyclerView.ViewHolder> {private var data = ArrayList<FunctionItem>()private val context: Contextconstructor(context: Context, data: ArrayList<FunctionItem>) {this.context = contextif (data != null) {this.data = data}}override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {return if (0 == viewType) {TitleViewHolder(DataBindingUtil.inflate(LayoutInflater.from(context),R.layout.layout_function_text, parent, false))} else {FunctionViewHolder(DataBindingUtil.inflate(LayoutInflater.from(context),R.layout.layout_grid_item, parent, false))}}override fun onBindViewHolder(viewHolder: RecyclerView.ViewHolder, position: Int) {if (0 == getItemViewType(position)) {var binding : ViewDataBinding = DataBindingUtil.getBinding(viewHolder.itemView)!!binding.setVariable(BR.name, data[position].mName)binding.executePendingBindings()//val holder = viewHolder as TitleViewHolder//holder.text.setText(data[position].mName)} else {var binding : ViewDataBinding = DataBindingUtil.getBinding(viewHolder.itemView)!!val fi = data[position]var funcItemViewBean = FuncItemViewBean()funcItemViewBean.BtnImgSrc = if (fi.mIsSelect) R.drawable.item_block_selected else R.drawable.item_block_addfuncItemViewBean.IvImgSrc = context.resources.getIdentifier(fi.mImageUrl, "drawable",context.packageName)funcItemViewBean.Name = fi.mNamebinding.setVariable(BR.funcItem, funcItemViewBean)binding.executePendingBindings()else R.drawable.ic_block_add)var layoutGridItemBinding = binding as LayoutGridItemBindinglayoutGridItemBinding.btn.setOnClickListener {val f = data[position]if (!f.mIsSelect) {if (listener != null) {if (listener!!.add(f)) {f.mIsSelect = truenotifyDataSetChanged()}}}}}}override fun getItemViewType(position: Int): Int {return if (data[position].isTitle) 0 else 1}override fun getItemCount(): Int {return data.size}inner class TitleViewHolder(dataBinding: ViewDataBinding) : RecyclerView.ViewHolder(dataBinding.root)inner class FunctionViewHolder(dataBinding: ViewDataBinding) : RecyclerView.ViewHolder(dataBinding.root)interface OnItemAddListener {fun add(item: FunctionItem): Boolean}private var listener: OnItemAddListener? = nullfun setOnItemAddListener(listener: OnItemAddListener) {this.listener = listener}}

package com.daobo.wand.ui.adapterimport androidx.recyclerview.widget.RecyclerViewimport com.daobo.wand.ui.listener.ItemTouchHelperAdapterimport com.daobo.wand.ui.FunctionItemimport android.content.Contextimport android.view.LayoutInflaterimport android.view.ViewGroupimport androidx.databinding.DataBindingUtilimport androidx.databinding.ViewDataBindingimport com.daobo.wand.BRimport com.daobo.wand.Rimport com.daobo.wand.databinding.LayoutGridItemBindingimport com.daobo.wand.ui.viewbean.FuncItemViewBeanimport java.util.*import kotlin.collections.ArrayListclass FunctionBlockAdapter: RecyclerView.Adapter<RecyclerView.ViewHolder>, ItemTouchHelperAdapter {private var data = ArrayList<FunctionItem>()private var context: Context? = nullconstructor(context: Context, data: ArrayList<FunctionItem>) {this.context = contextif (data != null) {this.data = data}}override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {return FunctionViewHolder(DataBindingUtil.inflate(LayoutInflater.from(context), R.layout.layout_grid_item, parent, false))}override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {val fi = data[position]var funcItemViewBean = FuncItemViewBean()funcItemViewBean.BtnImgSrc = R.drawable.item_block_deletefuncItemViewBean.IvImgSrc = context!!.resources.getIdentifier(fi.mImageUrl, "drawable",context!!.packageName)funcItemViewBean.Name = fi.mNamevar binding : ViewDataBinding = DataBindingUtil.getBinding(holder.itemView)!!binding.setVariable(BR.funcItem, funcItemViewBean)binding.executePendingBindings()var layoutGridItemBinding = binding as LayoutGridItemBindinglayoutGridItemBinding.btn.setOnClickListener {val fi = data.removeAt(position)if (listener != null) {listener!!.remove(fi)}notifyDataSetChanged()}}override fun getItemCount(): Int {return data.size}override fun onItemMove(holder: RecyclerView.ViewHolder, fromPosition: Int, targetPosition: Int) {if (fromPosition < data.size && targetPosition < data.size) {Collections.swap(data, fromPosition, targetPosition)notifyItemMoved(fromPosition, targetPosition)}}override fun onItemSelect(holder: RecyclerView.ViewHolder) {holder.itemView.scaleX = 0.8fholder.itemView.scaleY = 0.8f}override fun onItemClear(holder: RecyclerView.ViewHolder) {holder.itemView.scaleX = 1.0fholder.itemView.scaleY = 1.0f}override fun onItemDismiss(holder: RecyclerView.ViewHolder) {}inner class FunctionViewHolder(dataBinding: ViewDataBinding) : RecyclerView.ViewHolder(dataBinding.root)interface OnItemRemoveListener {fun remove(item: FunctionItem)}private var listener: OnItemRemoveListener? = nullfun setOnItemRemoveListener(listener: OnItemRemoveListener) {this.listener = listener}}

listener包下面定义的监听：

package com.daobo.wand.ui.listenerimport androidx.recyclerview.widget.ItemTouchHelperimport androidx.recyclerview.widget.RecyclerViewclass DefaultItemCallback : ItemTouchHelper.Callback {private var touchHelperAdapter: ItemTouchHelperAdapterconstructor(touchHelperAdapter: ItemTouchHelperAdapter) {this.touchHelperAdapter = touchHelperAdapter}override fun getMovementFlags(recyclerView: RecyclerView,viewHolder: RecyclerView.ViewHolder): Int {val dragFlags =ItemTouchHelper.UP or ItemTouchHelper.DOWN or ItemTouchHelper.LEFT or ItemTouchHelper.RIGHT //允许上下左右的拖动return ItemTouchHelper.Callback.makeMovementFlags(dragFlags, 0)}override fun onMove(recyclerView: RecyclerView,viewHolder: RecyclerView.ViewHolder,target: RecyclerView.ViewHolder): Boolean {touchHelperAdapter.onItemMove(viewHolder,viewHolder.adapterPosition,target.adapterPosition)return true}override fun onSelectedChanged(viewHolder: RecyclerView.ViewHolder?, actionState: Int) {if (actionState != ItemTouchHelper.ACTION_STATE_IDLE)touchHelperAdapter.onItemSelect(viewHolder!!)}override fun clearView(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder) {if (!recyclerView.isComputingLayout)touchHelperAdapter.onItemClear(viewHolder)}override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {}override fun isLongPressDragEnabled(): Boolean {return true}override fun isItemViewSwipeEnabled(): Boolean {return false}}

package com.daobo.wand.ui.listenerimport androidx.recyclerview.widget.ItemTouchHelperclass DefaultItemTouchHelper : ItemTouchHelper {constructor(callback: ItemTouchHelper.Callback): super(callback)}

package com.daobo.wand.ui.listenerimport androidx.recyclerview.widget.RecyclerViewinterface ItemTouchHelperAdapter {fun onItemMove(holder: RecyclerView.ViewHolder, fromPosition: Int, targetPosition: Int)fun onItemSelect(holder: RecyclerView.ViewHolder)fun onItemClear(holder: RecyclerView.ViewHolder)fun onItemDismiss(holder: RecyclerView.ViewHolder)}

注意：在layout_function_item binding imageview 的src 资源，我们需要定义下：

package com.daobo.wand.ui.utilimport android.os.Buildimport android.view.Viewimport android.widget.ImageViewimport androidx.annotation.RequiresApiimport androidx.core.content.res.ResourcesCompatimport androidx.databinding.BindingAdapterclass ImageBindingUtil {companion object {@BindingAdapter("android:src")@JvmStaticfun setSrc(view: ImageView, resId: Int) {view.setImageResource(resId)}@RequiresApi(Build.VERSION_CODES.JELLY_BEAN)@JvmStatic@BindingAdapter("background")fun setBackground(view: View, id: Int) {//view.resources.getDrawable(id)view.background = ResourcesCompat.getDrawable(view.resources, id, null)}}}

binding adapter方法只需要全局static 声明下，但是要使用注解@JvmStatic

工具类 用户来初始化数据，且将数据保存到preferences中：

package com.daobo.wand.ui.utilimport android.content.Contextimport android.content.SharedPreferencesimport com.daobo.wand.ui.FunctionItemimport com.daobo.wand.ui.TabItemimport com.google.gson.Gsonimport com.google.gson.reflect.TypeTokenimport java.io.BufferedReaderimport java.io.IOExceptionimport java.io.InputStreamReaderclass SFUtils {private var context: Context? = nullprivate var sp: SharedPreferences? = nullvar tabItems : ArrayList<TabItem> = ArrayList()constructor(context: Context) {this.context = contextsp = context.getSharedPreferences("menudata", Context.MODE_PRIVATE)initData()}/*** 把已有的菜单数据 配置到* assets menuData 配置文件中*/fun getAllFunctionWithState(): ArrayList<FunctionItem> {var allData = sp!!.getString("allData", "")var functionItems = ArrayList<FunctionItem>()var tabItems: List<TabItem>? = nullif ("" == allData) {try {val ins = context!!.assets.open("menuData.txt")val isr = InputStreamReader(ins)val br = BufferedReader(isr)var str: String? = br.readLine()val sbuf = StringBuffer()while (str != null) {sbuf.append(str)}br.close()isr.close()ins.close()allData = sbuf.toString()tabItems = Gson().fromJson(allData, object : TypeToken<List<TabItem>>(){}.type)if (tabItems != null) {for (i in tabItems!!.indices) {val functionItem = FunctionItem(tabItems[i].getTabName(), true)functionItems.add(functionItem)functionItems.addAll(tabItems[i].getFunctionItems()!!)}}} catch (e: IOException) {e.printStackTrace()}} else {functionItems = Gson().fromJson(allData, object : TypeToken<List<FunctionItem>>(){}.type)}return functionItems}/*** 把用户的选择 保存到Preferences 文件* 即使 app 推出运行，内存数据清理掉* */fun getSelectFunctionItem(): ArrayList<FunctionItem> {val selData = sp!!.getString("selData", "")var functionItems: ArrayList<FunctionItem>? = nullfunctionItems = if ("" == selData) {ArrayList()} else {Gson().fromJson(selData, object : TypeToken<List<FunctionItem>>(){}.type)}return functionItems!!}fun getAllFunctionItems () : ArrayList<FunctionItem>{var functionItems = ArrayList<FunctionItem>()for (i in tabItems!!.indices) {val functionItem = FunctionItem(tabItems[i].getTabName(), true)functionItems.add(functionItem)functionItems.addAll(tabItems[i].getFunctionItems()!!)}return functionItems}fun getTabFunctionItems(): ArrayList<FunctionItem> {var tabItemsCount = 0 //用于标记之后滑动的位置var functionItems = ArrayList<FunctionItem>()for (i in tabItems!!.indices) {val functionItem =FunctionItem(tabItems[i].getTabName(), true, tabItemsCount)tabItemsCount += tabItems[i].getFunctionItems()!!.size + 1functionItems.add(functionItem)}return functionItems}fun getTabNames(): ArrayList<FunctionItem> {var allData = sp!!.getString("allData", "")var functionItems = ArrayList<FunctionItem>()var tabItems: List<TabItem>? = nullif ("" == allData) {try {val ins = context!!.assets.open("menuData.txt")val isr = InputStreamReader(ins)val br = BufferedReader(isr)var str: String? = br.readLine()val sbuf = StringBuffer()while (str != null) {sbuf.append(str)}br.close()isr.close()ins.close()allData = sbuf.toString()tabItems = Gson().fromJson(allData, object : TypeToken<List<TabItem>>(){}.type)if (tabItems != null) {var tabItemsCount = 0 //用于标记之后滑动的位置for (i in tabItems!!.indices) {val functionItem =FunctionItem(tabItems[i].getTabName(), true, tabItemsCount)tabItemsCount += tabItems[i].getFunctionItems()!!.size + 1functionItems.add(functionItem)}}} catch (e: IOException) { e.printStackTrace() }}//else{// functionItems = Gson().fromJson(allData, object : TypeToken<List<FunctionItem>>(){}.type)// }return functionItems}fun saveSelectFunctionItem(selData: List<FunctionItem>) {sp!!.edit().putString("selData", Gson().toJson(selData)).apply()}fun saveAllFunctionWithState(allData: List<FunctionItem>) {sp!!.edit().putString("allData", Gson().toJson(allData)).apply()}private fun initData () {var arrayList : ArrayList<FunctionItem> = ArrayList()arrayList.add(FunctionItem("充值中心",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("信用卡还款",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("生活缴费",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("城市服务",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("生活号",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("我的客服",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("我的快递",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("医疗健康",false,"icon_home_selected","#86c751"))arrayList.add( FunctionItem("记账本",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("城市一卡通",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("发票管家",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("蚂蚁宝卡",false,"icon_home_selected","#86c751"))arrayList.add(FunctionItem("车主服务",false,"icon_home_selected","#86c751"))arrayList.add( FunctionItem("天天有料",false,"icon_home_selected","#86c751"))var tabItem : TabItem = TabItem("便民生活", arrayList)tabItems.add(tabItem)var arrayList1 : ArrayList<FunctionItem> = ArrayList()arrayList1.add(FunctionItem("余额宝",false,"icon_home_selected","#86c751"))arrayList1.add(FunctionItem("花呗",false,"icon_home_selected","#86c751"))arrayList1.add(FunctionItem("芝麻信用",false,"icon_home_selected","#86c751"))arrayList1.add(FunctionItem("蚂蚁借呗",false,"icon_home_selected","#86c751"))arrayList1.add(FunctionItem("股票",false,"icon_home_selected","#86c751"))arrayList1.add(FunctionItem("保险服务",false,"icon_home_selected","#86c751"))arrayList1.add(FunctionItem("汇率换算",false,"icon_home_selected","#86c751"))arrayList1.add(FunctionItem("理财小工具",false,"icon_home_selected","#86c751"))var tabItem1 : TabItem = TabItem("财务管理",arrayList1)tabItems.add(tabItem1)var arrayList2 : ArrayList<FunctionItem> = ArrayList()arrayList2.add(FunctionItem("转账",false,"icon_home_selected","#86c751"))arrayList2.add(FunctionItem("红包",false,"icon_home_selected","#86c751"))arrayList2.add(FunctionItem("AA收款",false,"icon_home_selected","#86c751"))arrayList2.add(FunctionItem("亲密付",false,"icon_home_selected","#86c751"))arrayList2.add(FunctionItem("上银汇款",false,"icon_home_selected","#86c751"))arrayList2.add(FunctionItem("话费卡转让",false,"icon_home_selected","#86c751"))var tabItem2 : TabItem = TabItem("资金往来",arrayList2)tabItems.add(tabItem2)var arrayList3 : ArrayList<FunctionItem> = ArrayList()arrayList3.add(FunctionItem("游戏中心",false,"icon_home_selected","#86c751"))arrayList3.add(FunctionItem("出境",false,"icon_home_selected","#86c751"))arrayList3.add(FunctionItem("彩票",false,"icon_home_selected","#86c751"))arrayList3.add(FunctionItem("人脸识别",false,"icon_home_selected","#86c751"))arrayList3.add(FunctionItem("奖励金",false,"icon_home_selected","#86c751"))arrayList3.add(FunctionItem("世界杯",false,"icon_home_selected","#86c751"))var tabItem3 : TabItem = TabItem("购物娱乐",arrayList3)tabItems.add(tabItem3)var arrayList4 : ArrayList<FunctionItem> = ArrayList()arrayList4.add(FunctionItem("大学生活",false,"icon_home_selected","#86c751"))arrayList4.add(FunctionItem("爱心捐赠",false,"icon_home_selected","#86c751"))arrayList4.add(FunctionItem("蚂蚁森林",false,"icon_home_selected","#86c751"))arrayList4.add(FunctionItem("蚂蚁庄园",false,"icon_home_selected","#86c751"))arrayList4.add(FunctionItem("中小学",false,"icon_home_selected","#86c751"))arrayList4.add(FunctionItem("运动",false,"icon_home_selected","#86c751"))var tabItem4 : TabItem = TabItem("教育公益",arrayList4)tabItems.add(tabItem4)var arrayList5 : ArrayList<FunctionItem> = ArrayList()arrayList5.add(FunctionItem("淘票票",false,"icon_home_selected","#86c751"))arrayList5.add(FunctionItem("滴滴出行",false,"icon_home_selected","#86c751"))arrayList5.add(FunctionItem("饿了么外卖",false,"icon_home_selected","#86c751"))arrayList5.add(FunctionItem("天猫",false,"icon_home_selected","#86c751"))arrayList5.add(FunctionItem("淘宝",false,"icon_home_selected","#86c751"))arrayList5.add(FunctionItem("火车票机票",false,"icon_home_selected","#86c751"))var tabItem5 : TabItem = TabItem("第三方服务",arrayList5)tabItems.add(tabItem5)}}

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