Pixelcat-App-Android/app/src/main/kotlin/at/connyduck/pixelcat/components/profile/GridSpacingItemDecoration.kt

52 lines
1.7 KiB
Kotlin

/*
* Copyright (C) 2020 Conny Duck
*
* This file is part of Pixelcat.
*
* Pixelcat is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Pixelcat is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
package at.connyduck.pixelcat.components.profile
import android.graphics.Rect
import android.view.View
import androidx.recyclerview.widget.RecyclerView
import androidx.recyclerview.widget.RecyclerView.ItemDecoration
class GridSpacingItemDecoration(
private val spanCount: Int,
private val spacing: Int,
private val topOffset: Int
) : ItemDecoration() {
override fun getItemOffsets(
outRect: Rect,
view: View,
parent: RecyclerView,
state: RecyclerView.State
) {
val position = parent.getChildAdapterPosition(view) // item position
if (position < topOffset) return
val column = (position - topOffset) % spanCount // item column
outRect.left = column * spacing / spanCount // column * ((1f / spanCount) * spacing)
outRect.right =
spacing - (column + 1) * spacing / spanCount // spacing - (column + 1) * ((1f / spanCount) * spacing)
if (position - topOffset >= spanCount) {
outRect.top = spacing // item top
}
}
}