polson

/*
 * Copyright (C) 2015 Jake Wharton
 * Modified work Copyright 2019 Phil Olson
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *

polson

class SmoothListAdapter(val context: Context) : ListAdapter<ListItem, ListItemViewHolder>(MyDiffCallback()) {

    data class ListItem(val id: String, val text: String)

    class ListItemViewHolder(view: View) : ViewHolder(view) {
        fun populateFrom(listItem: ListItem) {
            //TODO: populate your view
        }
    }

polson

object UIJobScheduler {
    private const val MAX_JOB_TIME_MS: Float = 4f

    private var elapsed = 0L
    private val jobQueue = ArrayDeque<() -> Unit>()
    private val isOverMaxTime get() = elapsed > MAX_JOB_TIME_MS * 1_000_000
    private val handler = Handler()

    fun submitJob(job: () -> Unit) {
        jobQueue.add(job)

polson

class MyView(context: Context) : FrameLayout(context) {
    private val viewModel by lazy { setupViewModel() }
    private val activity by lazy { scanForActivity(context) }

    private fun scanForActivity(context: Context?): FragmentActivity = when (context) {
        is FragmentActivity -> context
        is ContextWrapper -> scanForActivity(context.baseContext)
        else -> throw IllegalArgumentException("Context must be a FragmentActivity!")
    }

polson

    @Suppress("UNCHECKED_CAST")
    private inline fun <reified T : ViewModel> createViewModel(key: String, crossinline initializer: () -> T): T {
        val factory = object : ViewModelProvider.NewInstanceFactory() {
            override fun <T : ViewModel?> create(modelClass: Class<T>): T = initializer() as T
        }
        return ViewModelProviders.of(activity, factory).get(key, T::class.java)
    }

polson

private fun scanForActivity(context: Context?): FragmentActivity? = when (context) {
    is FragmentActivity -> context
    is ContextWrapper -> scanForActivity(context.baseContext)
    else -> throw IllegalArgumentException("Context must be a FragmentActivity!")
}

polson

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"

polson

/**
 * Provides a single instance of a class requiring a context.  Can be inherited by a companion
 * object to easily make it a singleton
 */
abstract class SingletonWithContext<T> {
    @Volatile
    private var instance: T? = null

    fun getInstance(context: Context): T =
            instance ?: synchronized(this) {

polson

class NormalActivity : AppCompatActivity(), NormalDialogFragment.NormalDialogListener {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_normal)

        val button = findViewById<Button>(R.id.normalButton)
        button.setOnClickListener { showNormalDialog() }
    }

    private fun showNormalDialog() =

polson

class BetterActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val button = findViewById<Button>(R.id.button)
        button.setOnClickListener { showBetterDialog() }

        val normalButton = findViewById<Button>(R.id.normalButton)
        normalButton.setOnClickListener { launchNormalActivity() }