alwarren

import java.text.DateFormat
import java.text.SimpleDateFormat

// Top-level build file where you can add configuration options common to all sub-projects/modules.

// your other gradle code here

static def getDateTime() {
    DateFormat df = new SimpleDateFormat("YYYYMMddHHmm");
    return df.format(new Date());

alwarren

Task: Manually add a Java module in Android Studio

Steps

1. Switch to Project view.
2. In the project root folder, create a folder with a unique identifiable name for the module. This folder becomes the root folder for the module.
3. Within the module's root folder, create a src/main/java folder.
4. Within the module's root folder, create a build.gradle file.
5. Within the module's build.gradle, insert the following two lines:

alwarren

// See https://medium.com/@iammert/using-diffutil-in-android-recyclerview-bdca8e4fbb00

fun <T> RecyclerView.Adapter<*>.autoNotify(oldList: List<T>, newList: List<T>, compare: (T, T) -> Boolean) {
    val diff = DiffUtil.calculateDiff(object : DiffUtil.Callback() {

        override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
            return compare(oldList[oldItemPosition], newList[newItemPosition])
        }

        override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {

alwarren

import android.os.Build
import android.util.Log
import okhttp3.ConnectionSpec
import okhttp3.OkHttpClient
import okhttp3.TlsVersion
import java.io.IOException
import java.net.InetAddress
import java.net.Socket
import java.net.UnknownHostException
import java.security.KeyStore

alwarren

import okhttp3.*
import retrofit2.Call
import retrofit2.Retrofit
import retrofit2.converter.scalars.ScalarsConverterFactory
import retrofit2.http.GET

import java.io.File
import java.io.IOException
import java.security.cert.X509Certificate
import javax.net.ssl.SSLContext

alwarren

apply plugin: 'com.android.library'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'kotlin-kapt'

android {
    compileSdkVersion 27
    defaultConfig {
        minSdkVersion 19
        targetSdkVersion 27

alwarren

/**
 * A helper class for building REST API endpoints.
 */
class Endpoint(
        val path: String,
        val query: String,
        val value: String) {

    // Returns a list of objects containing a subset of object properties
    class Filter {

alwarren

A composable pattern for pure state machines with effects

State machines are everywhere in interactive systems, but they're rarely defined clearly and explicitly. Given some big blob of code including implicit state machines, which transitions are possible and under what conditions? What effects take place on what transitions?

There are existing design patterns for state machines, but all the patterns I've seen complect side effects with the structure of the state machine itself. Instances of these patterns are difficult to test without mocking, and they end up with more dependencies. Worse, the classic patterns compose poorly: hierarchical state machines are typically not straightforward extensions. The functional programming world has solutions, but they don't transpose neatly enough to be broadly usable in mainstream languages.

Here I present a composable pattern for pure state machiness with effects,

alwarren

/*
 * Copyright (c) 2017 Emil Davtyan
 * 
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:

alwarren

fun Context.colorInt(color: Int) = ContextCompat.getColor(this, color)

inline fun View.snack(@IntegerRes messageRes: Int, length: Int = Snackbar.LENGTH_LONG, f: Snackbar.() -> Unit) {
    snack(resources.getString(messageRes), length, f)
}

inline fun View.snack(message: String, length: Int = Snackbar.LENGTH_LONG, f: Snackbar.() -> Unit) {
    val snack = Snackbar.make(this, message, length)
    snack.f()
    snack.show()