android - Dan Lew Codes (Page 2)

Sync Failure Handling

This article is part 3 of a series (1, 2, 3, 4, 5, 6, 7) In the last article we discussed how we sync our changes with the server. Ideally, those HTTP requests would always work - if only we could walk the rosy path of best-case scenarios! Unfortunately, when

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Syncing Changes

This article is part 2 of a series (1, 2, 3, 4, 5, 6, 7) Going offline meant using our database for all immediate changes to the client. But obviously we later want to sync those changes with the server. The basic idea behind our sync is to store changes

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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

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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 notifications allow

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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 and

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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 most confusing RxJava operators,

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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

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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.

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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

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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. The deadline

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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 tests (located

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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

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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

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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

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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 versions

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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

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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 started

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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

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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_

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Pseudolocalization: Visiting Android's Bizarro World

I wrote a while ago about pseudolocalization on Android [https://blog.danlew.net/2014/04/16/android-localization-tips/] but times have changed and I wanted to give an update. Pseudolocalization [http://en.wikipedia.org/wiki/Pseudolocalization] is a developer testing method that automatically translates your strings files into gibberish, with extra

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Setting up a new app in Crashlytics without the IDE plugin

I like Crashlytics [https://crashlytics.com/]. I like the service they provide: their crash logs have saved my ass countless times. I also like that it's free. However, there is one problem I've run into time and time again: getting new apps setup with it. They

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A Guide to Lollipop Notification Settings

Lollipop changed the notification settings we all knew and loved but in a rather unintuitive way. It's so unintuitive I felt the need to write this guide. In short: you can do (almost1) everything you used to be able to do and more! It's just confusing

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Handling Android resources with non-standard formats

In Android you have to deal with a large variety of screen sizes. The current solution is to use adaptive design to handle all the screens. One concept of adaptive design is that you have ever-growing content frames... up to a point. Once the device is too large or wide,

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An animated drawable issue in Lollipop

A common pattern in Android is to use View.setVisibility() to swap widgets in your hierarchy. Unfortunately, in Lollipop, there is a risk of running afoul of the new RippleDrawable [https://developer.android.com/reference/android/graphics/drawable/RippleDrawable.html] when doing so. Let's look at a sample

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I don't need your permission!

Permissions on Android are tricky to get right from a user perspective. Usually you only want to do something minor and innocuous (pre-fill a form with a contact's info) but the actual permission you have to request gives you much more power than necessary (access to ALL contact