roschlau

class Event<T> {
    private val handlers = arrayListOf<(T) -> Unit>()
    operator fun plusAssign(handler: (T) -> Unit) { handlers.add(handler) }
    operator fun invoke(value: T) { for (handler in handlers) handler(value) }
}

val e = Event<String>() // define event

fun main(args : Array<String>) {
    e += { println(it) } // subscribe

roschlau

class Repeater(val interval: Long,
               val context: CoroutineContext = UI,
               val block: () -> Unit
) {
    private var updatingJob: Job? = null
    private val updatingJobLock = Any()

    fun start() = synchronized(updatingJobLock) {
        if (updatingJob != null && updatingJob!!.isActive) {
            return

roschlau

import android.support.v7.util.DiffUtil

open class DiffUtilCallback<T>(val oldList: List<T>, val newList: List<T>) : DiffUtil.Callback() {

    override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int)
        = oldList[oldItemPosition] == newList[newItemPosition]

    override fun getOldListSize()
        = oldList.size

roschlau

import android.graphics.Rect;
import android.support.v7.widget.RecyclerView;
import android.view.View;

public class GridSpacingDecoration extends RecyclerView.ItemDecoration {

    private int cols;
    private int spacing;

    public GridSpacingDecoration(int cols, int spacing) {