Question

您好，我是Kotlin的新手，我有近1个月的编程，我有一个回收商，我试图在回收商中重新订购卡片，并删除那些我不会需要通过刷它，我怎么能实现这一目标？可以用图书馆来完成吗？我找不到一个

这就是我所拥有的：

适配器

    open class EmployeesAdapter(var context: Context, var employee:ArrayList<EmployeesTest>):BaseAdapter() {

    private class ViewHolder(row: View?) {

        var txt_user: TextView
        var user_job: TextView
        var img_user: ImageView
        var checBox: CheckBox

        init {
            this.txt_user = row?.findViewById(R.id.txt_user) as TextView
            this.img_user = row.findViewById(R.id.img_user) as ImageView
            this.user_job = row.findViewById(R.id.user_job) as TextView
            this.checBox = row.findViewById(R.id.checkBox) as CheckBox


        }
    }

    override fun getView(position: Int, convertView: View?, parent: ViewGroup?): View {

        var view: View
        var viewHolder: ViewHolder
        if (convertView == null) {
            var layout = LayoutInflater.from(context)
            view = layout.inflate(R.layout.employee_list_item, parent, false)
            viewHolder = ViewHolder(view)
            view.tag = viewHolder
        } else {
            view = convertView
            viewHolder = view.tag as ViewHolder
        }
        var employees:EmployeesTest=getItem(position) as EmployeesTest
        viewHolder.txt_user.text = employees.nombre
        viewHolder.img_user.setImageResource(employees.profilePic)
        viewHolder.user_job.text = employees.cargo
        viewHolder.checBox.isChecked = false

        return view

    }

    override fun getItem(position: Int): Any {
        return employee[position]
    }

    override fun getItemId(position: Int): Long {
        return  position.toLong()
    }

    override fun getCount(): Int {
        return employee.count()
    }
}

活动

    class EditEmployeeFragment : Fragment() {
    var tv_name: TextView? = null
    var rel_main: RelativeLayout? = null


    override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        var view:View?=inflater!!.inflate(R.layout.edit_employee_fragment,container,false)

        var arrReports: ArrayList<EmployeesTest>? = ArrayList()
        arrReports?.add(EmployeesTest("Heber","Desarrollador",R.drawable.img_user))
        arrReports?.add(EmployeesTest("Mata","Desarrollador",R.drawable.img_user))
        arrReports?.add(EmployeesTest("Ernesto","Desarrollador",R.drawable.img_user))
        arrReports?.add(EmployeesTest("Toño","Desarrollador",R.drawable.img_user))

        var recyclerView:RecyclerView=view?.findViewById(R.id.recycler_edit_employees) as RecyclerView
        recyclerView.layoutManager = LinearLayoutManager(this.context, LinearLayout.VERTICAL, false)
        recyclerView.adapter = EditEmployeesAdapter( arrReports!!)
        return view
    }

}

谢谢你的帮助

Answer 1

This可能有所帮助。这是一个如何实现您正在寻找的教程。这需要一些编码 - 但它是可行的和可维护的解决方案（我在几个项目中使用过它）

PS：是的，这个问题与Kotlin无关;）

Answer 2

您需要 itemTouchHelper 。

<强>活动

recyclerView.addItemDecoration（DividerItemDecoration（this，DividerItemDecoration.VERTICAL）） recyclerView.layoutManager = LinearLayoutManager（this） recyclerView.adapter = simpleAdapter

    val swipeHandler = object : SwipeToDeleteCallback(this) {
        override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
            val adapter = recyclerView.adapter as SimpleAdapter
            adapter.removeAt(viewHolder.adapterPosition)
        }
    }
    val itemTouchHelper = ItemTouchHelper(swipeHandler)
    itemTouchHelper.attachToRecyclerView(recyclerView)

<强> SwipeToDeleteCallback

abstract class SwipeToDeleteCallback(context: Context) : ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {

private val deleteIcon = ContextCompat.getDrawable(context, R.drawable.ic_delete_white_24)
private val intrinsicWidth = deleteIcon.intrinsicWidth
private val intrinsicHeight = deleteIcon.intrinsicHeight
private val background = ColorDrawable()
private val backgroundColor = Color.parseColor("#f44336")
private val clearPaint = Paint().apply { xfermode = PorterDuffXfermode(PorterDuff.Mode.CLEAR) }


override fun getMovementFlags(recyclerView: RecyclerView?, viewHolder: RecyclerView.ViewHolder?): Int {
    /**
     * To disable "swipe" for specific item return 0 here.
     * For example:
     * if (viewHolder?.itemViewType == YourAdapter.SOME_TYPE) return 0
     * if (viewHolder?.adapterPosition == 0) return 0
     */
    if (viewHolder?.adapterPosition == 10) return 0
    return super.getMovementFlags(recyclerView, viewHolder)
}

override fun onMove(recyclerView: RecyclerView?, viewHolder: RecyclerView.ViewHolder?, target: RecyclerView.ViewHolder?): Boolean {
    return false
}

override fun onChildDraw(
        c: Canvas?, recyclerView: RecyclerView?, viewHolder: RecyclerView.ViewHolder,
        dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean
) {

    val itemView = viewHolder.itemView
    val itemHeight = itemView.bottom - itemView.top
    val isCanceled = dX == 0f && !isCurrentlyActive

    if (isCanceled) {
        clearCanvas(c, itemView.right + dX, itemView.top.toFloat(), itemView.right.toFloat(), itemView.bottom.toFloat())
        super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
        return
    }

    // Draw the red delete background
    background.color = backgroundColor
    background.setBounds(itemView.right + dX.toInt(), itemView.top, itemView.right, itemView.bottom)
    background.draw(c)

    // Calculate position of delete icon
    val deleteIconTop = itemView.top + (itemHeight - intrinsicHeight) / 2
    val deleteIconMargin = (itemHeight - intrinsicHeight) / 2
    val deleteIconLeft = itemView.right - deleteIconMargin - intrinsicWidth
    val deleteIconRight = itemView.right - deleteIconMargin
    val deleteIconBottom = deleteIconTop + intrinsicHeight

    // Draw the delete icon
    deleteIcon.setBounds(deleteIconLeft, deleteIconTop, deleteIconRight, deleteIconBottom)
    deleteIcon.draw(c)

    super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
}

private fun clearCanvas(c: Canvas?, left: Float, top: Float, right: Float, bottom: Float) {
    c?.drawRect(left, top, right, bottom, clearPaint)
}
}

看一下不错的例子

https://github.com/kitek/android-rv-swipe-delete

Answer 3

val itemTouchHelperCallback =
            object :
                ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT or ItemTouchHelper.RIGHT) {
                override fun onMove(
                    recyclerView: RecyclerView,
                    viewHolder: RecyclerView.ViewHolder,
                    target: RecyclerView.ViewHolder
                ): Boolean {

                    return false
                }

                override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
                    noteViewModel.delete(noteAdapter.getNoteAt(viewHolder.adapterPosition))
                    Toast.makeText(
                        this@MainActivity,
                        getString(R.string.note_deleted),
                        Toast.LENGTH_SHORT
                    ).show()
                }

            }

        val itemTouchHelper = ItemTouchHelper(itemTouchHelperCallback)
        itemTouchHelper.attachToRecyclerView(rvNote)

Answer 4

与Sana相同的答案，但使用SnackBar允许对删除执行“ UNDO”操作：

归因：部分受https://www.journaldev.com/23164/android-recyclerview-swipe-to-delete-undo启发

val itemTouchHelperCallback =
    object :
        ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT or ItemTouchHelper.RIGHT) {
        override fun onMove(
            recyclerView: RecyclerView,
            viewHolder: RecyclerView.ViewHolder,
            target: RecyclerView.ViewHolder
        ) = false

        override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
            val position = viewHolder.adapterPosition
            val note: Note = noteAdapter.getNoteAt(position)

            noteViewModel.delete(note)

            Snackbar.make(
                coordinator_layout, // The ID of your coordinator_layout
                getString(R.string.note_deleted),
                Snackbar.LENGTH_LONG
            ).apply {
                setAction("UNDO") {
                    noteViewModel.create(note)
                    // If you're not using LiveData you might need to tell the adapter
                    // that an item was inserted: notifyItemInserted(position);
                    rvNote.scrollToPosition(position)
                }
                setActionTextColor(Color.YELLOW)
            }.show()
        }
    }
ItemTouchHelper(itemTouchHelperCallback).apply {
            attachToRecyclerView(rvNote)
        }

如何在recyclerview中实施，拖放和滑动删除？

4 个答案: