android Airplane Mode: Enabling Trello Mobile Offline This article is part 1 of a series (1, 2, 3, 4, 5, 6, 7) Good news, everyone! The Trello mobile apps now work offline! Offline mode has been the most requested mobile feature for years. It’s frustrating to lose the ability to use Trello when you enter the
android Correctly handling bundled Android notifications Bundled notifications on Android are a tricky business. Individual, fire-and-forget notifications are simple. You create a Notification [https://developer.android.com/reference/android/app/Notification.html], send it to NotificationManagerCompat [https://developer.android.com/reference/android/support/v4/app/NotificationManagerCompat.html] , and the system handles the rest. Bundled
Code Deliberately All code should have a purpose. There should be just as much code as necessary to execute your goals and no more. Unintentional or unnecessary code raises many difficult questions: What is the purpose of this code? Is this code actually important? Did this code ever work? By contrast, intentional
android The Activity lifecycle vs. the world A common problem people run into with Activities are handling runtime configuration changes [http://developer.android.com/guide/topics/resources/runtime-changes.html]. This situation ought to sound familiar: 1. The user initiates a network request in an Activity. 2. The user rotates the screen. 3. The Activity is destroyed
android Year in Review (2016) In case you missed it... here is all the public activity I've done in the last year. Articles * RxJava's repeatWhen and retryWhen, explained [https://blog.danlew.net/2016/01/25/rxjavas-repeatwhen-and-retrywhen-explained/] I found repeatWhen and retryWhen to be a couple of the
android Trello Android Schema Upgrades For many years, Trello Android has used a simple system for upgrading the database schema: drop the entire database, recreate it, and repopulate the data from the server! While far from ideal, this solution worked because the Trello server was the only source of truth. Any change you made in
android A deep dive into Android View constructors I often see confusion around Android View constructors. Why are there four of them? What does each parameter do? Which constructors do I need to implement? tl;dr If you just want quick, practical advice, here's a few good guidelines: * Use View(Context) for creating Views in code.
rxjava Multicasting in RxJava Multicasting is a key method for reducing duplicated work in RxJava. When you multicast an event, you send the same event to all downstream operators/subscribers. This is useful when you're doing an expensive operation like a network request. You don't want to repeatedly execute identical
speaking How I write tech talks A few people have asked me recently about writing talks, so I thought I'd document my process. I only write technical talks, so keep in mind that some of this advice may not apply for your talk. Goals I have two goals in mind for any talk: 1.
Unlimited vacation policies are inherently unfair Unlimited vacation policies are often painted as a dream benefit that only happens in cushy tech jobs, but I think they're inherently unfair because they're entirely subjective. It's easy to prove that unlimited vacation policies are anything but: no company would allow you to
rxjava RxJava's repeatWhen and retryWhen, explained repeatWhen [http://reactivex.io/RxJava/javadoc/rx/Observable.html#repeatWhen(rx.functions.Func1)] and retryWhen [http://reactivex.io/RxJava/javadoc/rx/Observable.html#retryWhen(rx.functions.Func1)] are fairly baffling at first glance. For starters, they are serious contenders for "most confusing marble diagrams": They're useful
android Making EditTexts with links both clickable and editable Recently, I was working on an EditText [http://developer.android.com/reference/android/widget/EditText.html] that supports links. That is, users can add URLs that become clickable when not editing. When the EditText is not focused, the links should be clickable. However, when it is focused, it should disable
rxjava Error handling in RxJava RxJava makes error handling a snap. Just use onError, right? That's fine and dandy if you're the subscriber, but what about exceptions that occur inside your operators? How do you ensure that an Exception in, say, flatMap() gets passed along to onError? And what if you
android My First Android App, Six Years Later Allow me to indulge in a bit of throw-back-Thursday reminiscing as I look back on my first ever Android app: FlightTrack. In October of 2009 I joined a small travel app startup, Mobiata, and was tasked with writing the Android version of its already successful iOS app FlightTrack.
android Sharing code between unit tests and instrumentation tests on Android Edit (August 16, 2022): This method is outdated and no longer works on the latest versions of Android Studio. See my new guide for an up-to-date solution on this problem. Suppose you've got an Android application with a bunch of tests. Some of them are unit
android Using hardware layers to improve Android animation performance When someone asks me about poor animation performance, one of the first questions I ask is whether or not they are using hardware layers. During animations your views may be redrawn each frame. If you use view layers, instead of having to redraw each frame, views render once into an
android Beware EditText on API 21 Check out these two EditTexts. One is on an API 21 device, the other on an API 22 device. See the difference? It's even more pronounced with "show layout bounds" enabled: The height and vertical alignment of the EditTexts are different! This was caused by a
android Sharing files on Android in a world with runtime permissions There are some growing pains we're going to experience while upgrading to runtime permissions. The most painful one I've run into so far is sharing files. When done correctly, sharing a file involves a sender app creating an accessible URI and a receiver app reading a
android Don't use dynamic versions for your dependencies Everyone, please, to stop using dynamic versions for your dependencies. In Gradle, dynamic versions use the + sign like so: compile 'com.android.support:appcompat-v7:23.0.+' Ideally, your builds should be predictable and consistent. Identical source code should yield the same result, every time you build. Dynamic
android How to upgrade to RxAndroid 1.0 A number of people have asked me recently, "What the hell happened to RxAndroid [https://github.com/ReactiveX/RxAndroid]?" The fact of the matter is, RxAndroid was getting to be a bit of a mess and thus has been majorly refactored. You can read more about it here
rxjava Deferring Observable code until subscription in RxJava I've grown fond of RxJava's defer() [http://reactivex.io/documentation/operators/defer.html] as a tool for ensuring Observable code runs when subscribed (rather than when created). I've written about defer() before [http://blog.danlew.net/2014/10/08/grokking-rxjava-part-4/#oldslowcode]
rxjava Loading data from multiple sources with RxJava Suppose I have some Data that I query from the network. I could simply hit the network each time I need the data, but caching the data on disk and in memory would be much more efficient. More specifically, I want a setup that: 1. Occasionally performs queries from the
android Recent presentations and code I've been quite busy in the past several months! Talk: An Introduction to Groovy and Gradle I had been using Gradle-based Android builds for a long time before actually bothering to try to understand what's going on in them. This talk will help get you
android Lessons learned from our first Gradle plugin for Android, Victor The Android team at Trello is happy to announce our first open source Android library, Victor [https://github.com/trello/victor]! It's a Gradle plugin that lets you use SVGs as resources in your Android apps. Victor started as a request from our designers. They were regularly creating
android Is your user a goat? Last updated August 17, 2015 Android isn't always serious business. Here are some of the sillier parts of the Android SDK. Useful The following do real things but have amusing names. FEATURE_TOUCHSCREEN_MULTITOUCH_JAZZHAND [http://developer.android.com/reference/android/content/pm/PackageManager.html#FEATURE_TOUCHSCREEN_MULTITOUCH_
