While writing what was intended to be the final post of this series, a discussion of predictive animations, I ran into a number of interesting challenges that I thought warranted their own discussion. This series began as an investigation into whether RecyclerView could easily handle a layout structure that could scroll in both the horizontal and vertical axes, and how difficult it would be for the developer to build their own LayoutManager. I chose a basic grid of uniform items as the structure, thinking it would be the most straightforward to implement.
In the previous post, we discussed adding proper support for data set changes and targeted scrolling. In this installment of the series, we will focus on properly supporting animations in your fancy new LayoutManager.
Styles and Themes are a great thing. They allow us to abstract common view properties into a single location, making the look and feel of our application UI more consistent and easier to maintain. If you look at Google’s UI guide for Styles and Themes, it mentions the motivation behind this as a separation between design logic and content.
In the last post, we walked through the core functionality necessary for building a RecyclerView LayoutManager. In this post, we are going to add support for a few additional features that the average adapter-based view is expected to have.
By now, if you’re an Android developer paying any attention, you’ve at least heard of RecyclerView; a new component that will be added to the support library to facilitate custom implementations of high-performance view collections by facilitating view recycling. Others have already done a remarkable job describing the basics of how to use RecyclerView with the built-in pieces already provided, including item animations.
The Drawable framework in Android is a neat and really flexible way to create portions of your UI. Many times have I been able to simplify the view hierarchy or required resources just by getting creating with what a Drawable can do. Recently, I had a need to place text into a Drawable so it could be inserted in places where the framework only allows Drawables to go. So I created TextDrawable and though I’d share it.
Since its inception, one of the key elements of the Android platform has been the tools provided in its resource framework to select appropriate assets tailored to the user’s device type. Over time, this system has been added to here and there to include differentiators for different screen sizes, resolution densities, presence of different hardware items like keyboards, and so on. Undoubtedly, the most common use of this system is to create differentiation for different screen configurations (both size and resolution density). As the Android device landscape has grown, developers like myself have found themselves struggling to keep up with the additions Google is making to the SDK to allow applications to properly adapt.
Android has a pretty flexible framework for displaying data from a database, array, or other list structure using classes called Adapters. There are plenty of great tutorials in the Android docs and throughout the web on how to use adapters to create custom behavior for display this data, so I’m going to focus on it’s less-discussed couterpart; the AdapterView. …
Developing UI layouts for Android is an experience unlike any other. I have developed for both desktop and mobile on a variety of platforms, and the XML structure that Android uses is quite unique. This can bring with it some issues and challenges as it runs contrary to the way many people think about designing their UI. Today, I’m going to make some comments on questions that I see constantly regarding the XML keywords most commonly misused in creating layouts. …
We’re all familiar with the concept of providing a temporary modal view to the user in an application for the purposes of notification or basic data entry. In the Android framework (as in many computer systems) a class is provided to the developer to create and maintain these views called a Dialog. This class is then further extended for you to make some convenient versions that allow entry of date/time information and make basic list selections (AlertDialog, TimePickerDialog, etc.). These classes work really well, and I would encourage you to leverage them whenever possible. …