Android FixedColumnsHorizontalGridLayoutManager

FixedColumnsHorizontalGridLayoutManager.kt

class FixedColumnsHorizontalGridLayoutManager(context: Context?, spanCountVertical: Int, private var columns: Int, orientation: Int, reverseLayout: Boolean) :
  GridLayoutManager(context, spanCountVertical, orientation, reverseLayout) {

  private val safeWidth: Int
    get() = width - paddingRight - paddingLeft

  override fun generateDefaultLayoutParams(): RecyclerView.LayoutParams = spanLayoutSize(super.generateDefaultLayoutParams())
  override fun generateLayoutParams(context: Context, attrs: AttributeSet): RecyclerView.LayoutParams = spanLayoutSize(super.generateLayoutParams(context, attrs))
  override fun generateLayoutParams(layoutParams: ViewGroup.LayoutParams): RecyclerView.LayoutParams = spanLayoutSize(super.generateLayoutParams(layoutParams))

  private fun spanLayoutSize(layoutParams: RecyclerView.LayoutParams): RecyclerView.LayoutParams {
    if (orientation == HORIZONTAL) layoutParams.width =
      round(safeWidth.toDouble() / columns).toInt() else throw IllegalArgumentException("LayoutManager orientation must be GridLayoutManager.HORIZONTAL")
    return layoutParams
  }
}