RecyclerView 条目滑动删除辅助类

RecyclerView 条目滑动删除辅助类

import android.annotation.SuppressLint
import android.content.Context
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.drawable.ColorDrawable
import android.view.MotionEvent
import androidx.core.content.ContextCompat
import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.RecyclerView
import com.benefit.workbox.widget.R

class SwipeDeleteHelper(
    private val context: Context,
    private val recyclerView: RecyclerView,
    private val itemWidthDp: Int = 88, // 删除区域宽度(dp)
    private val revealThreshold: Float = 0.3f, // 显示删除图标的阈值比例
    private val deleteIconResId: Int = R.drawable.svg_gray_delete, // 删除图标资源ID
    private val backgroundColor: Int = Color.TRANSPARENT, // 背景颜色
    private val onItemDeleteListener: (position: Int) -> Unit, // 删除回调
) {

    private val itemWidthPx: Int
    private var swipingViewHolder: RecyclerView.ViewHolder? = null
    private var deleteAreaBounds: android.graphics.Rect? = null

    init {
        itemWidthPx = dpToPx(context, itemWidthDp)
        setupSwipeToDelete()
        setupTouchListener()
    }

    private fun setupSwipeToDelete() {
        val simpleCallback = object : ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {

            private val background = ColorDrawable(backgroundColor)
            private val deleteIcon = ContextCompat.getDrawable(context, deleteIconResId)
            private val intrinsicWidth = deleteIcon?.intrinsicWidth ?: 0
            private val intrinsicHeight = deleteIcon?.intrinsicHeight ?: 0

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

            override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
                // 不自动删除，由区域点击触发
            }

            override fun onChildDraw(
                c: Canvas,
                recyclerView: RecyclerView,
                viewHolder: RecyclerView.ViewHolder,
                dX: Float,
                dY: Float,
                actionState: Int,
                isCurrentlyActive: Boolean,
            ) {
                // 限制最大滑动距离
                val limitedDx = -itemWidthPx.coerceAtMost(-dX.toInt()).toFloat()

                // 计算滑动比例
                val swipeProgress = Math.abs(limitedDx) / itemWidthPx

                val itemView = viewHolder.itemView
                val itemHeight = itemView.bottom - itemView.top

                // 绘制删除背景（覆盖整个删除区域）
                background.alpha = (255 * swipeProgress).toInt()
                background.setBounds(
                    itemView.right - itemWidthPx,
                    itemView.top,
                    itemView.right,
                    itemView.bottom
                )
                background.draw(c)

                // 保存删除区域的边界，用于点击检测
                if (isCurrentlyActive) {
                    deleteAreaBounds = android.graphics.Rect(
                        itemView.right - itemWidthPx,
                        itemView.top,
                        itemView.right,
                        itemView.bottom
                    )
                    swipingViewHolder = viewHolder
                }

                // 只有当滑动超过阈值时才显示删除图标
                if (swipeProgress >= revealThreshold) {
                    // 计算删除图标位置（在删除区域内居中）
                    val iconLeft = itemView.right - itemWidthPx + (itemWidthPx - intrinsicWidth) / 2
                    val iconRight = iconLeft + intrinsicWidth
                    val iconTop = itemView.top + (itemHeight - intrinsicHeight) / 2
                    val iconBottom = iconTop + intrinsicHeight

                    deleteIcon?.setBounds(iconLeft, iconTop, iconRight, iconBottom)
                    deleteIcon?.draw(c)
                }

                // 移动内容视图
                itemView.translationX = limitedDx
            }

            override fun getSwipeThreshold(viewHolder: RecyclerView.ViewHolder): Float {
                return 0.5f // 需要滑动超过一半才认为完成滑动
            }
        }

        val itemTouchHelper = ItemTouchHelper(simpleCallback)
        itemTouchHelper.attachToRecyclerView(recyclerView)
    }

    @SuppressLint("ClickableViewAccessibility")
    private fun setupTouchListener() {
        recyclerView.setOnTouchListener { _, event ->
            handleTouchEvent(event)
            false
        }
    }

    private fun handleTouchEvent(event: MotionEvent) {
        if (event.action == MotionEvent.ACTION_UP && swipingViewHolder != null && deleteAreaBounds != null) {
            val viewHolder = swipingViewHolder!!
            val bounds = deleteAreaBounds!!

            // 检查触摸点是否在删除区域内
            if (bounds.contains(event.x.toInt(), event.y.toInt())) {
                val position = viewHolder.bindingAdapterPosition
                if (position != RecyclerView.NO_POSITION) {
                    // 触发删除回调
                    onItemDeleteListener(position)
                    // 重置状态
                    swipingViewHolder = null
                    deleteAreaBounds = null
                }
            }

        }
    }

    private fun dpToPx(context: Context, dp: Int): Int {
        val density = context.resources.displayMetrics.density
        return (dp * density).toInt()
    }
}

使用方法

SwipeDeleteHelper(
    context = this,
    recyclerView = binding.rvList,
) { position ->
}

展示效果