When I built six apps in under 4 weeks

While looking for a new job, I've been thinking about how I quantify the work I've done previously, and I remember the time I built six apps in less than four weeks!

We didn't start from scratch, but compared to everything I have as a reference, it was fast work. I miss working on projects where the goal was to ship high-quality products regularly, and they would be used by lots of people.

So, backing up, the project was a port of existing apps that existed for other mobile platforms. The apps were "city guides" for different cities and were based on published pocket guides for those cities. The apps contained interactive maps of each city to enable the exploration of places of interest. It was also possible to create a custom itinerary of places to visit. Not massively complicated, but for a recognised brand that expected the highest quality.

Six apps, one for each of six cities.

Before we started, all the existing data and assets from the existing apps were gathered, a full review of the existing apps was performed (by everyone involved), and the designer from the agency created visual mock-ups for each of the "pages" in the app.

The [book] publisher hired an agency to build the apps, and the agency sub-contracted out the development to me. As a highly recognised agency, who did work I admired, they were one of the few companies I had always wanted to work for/with.

Prior to starting development, we held a meeting with the designer, product manager, agency owner, and myself to go through everything, ensure all requirements and details were known, and that everything was understood.

The plan was to build a single "core app" that could be "white-labelled". By providing different data files and visual assets, each of the six apps could be produced from a single codebase. I'd used a similar technique before when needing to build localised versions of an app for different countries, each with its own unique content and language.

Here's how the work broke down week by week.

Week 1: Build the custom map control. Without this, there would have been no app. It was the centrepiece of the application: unique functionality that differentiated it from other available apps. Yes, the whole first week was spent entirely on building a single control. It was, obviously, a complex control that contained a lot of functionality. All the functionality had to be easily testable too. It wasn't practical to travel to each city (on 3 different continents) to manually test the functionality.

Week 2: Get all the data in a consistent format. The provided data was in multiple formats. Mostly a mix of CSV files and SQLite databases. So, before building the actual mobile apps, I built a console app that would take all the different data sources and produce standardised, consistently formatted data that could be used by each app the same way. The existing apps embedded and used the raw data files, but it meant that they had to handle all the variations in file formats, data formatting, and incomplete data. Having data in a known and consistent format meant the code in the mobile app didn't have to account for as many variations or possible error conditions. It meant less code and less error handling. When updated data files were available, they could be reprocessed by the console app, and the files it produced were tested for consistency and correctness.

Week 3: Build the app. With all the complexities handled in the previous week, this became a case of building pages for the app(s) that displayed and allowed interaction with the data (& map control). I recall there being fewer than twenty pages in the app. Many pages were reused for different scenarios where the same basic structure could show very different data. These were pretty simple pages to display and interact with a fixed set of data. The challenging work in determining how the pages should look and the possible variations in data had all been considered prior to actually building the UI. This was key to building fast and correctly.

Week 4: Test the app. While doing some final tweaks and checks, I checked and retested everything while the agency's dedicated tester also did the same. Some additional automated checks/tests were also added. Across the entire code base, there were over 32000 tests, but many of these were for checking the data's validity, formatting, & consistency for each place of interest.

One particular memory I have was with the person from the agency responsible for testing the apps before release. They couldn't find any problems with any of the apps. However, like many people responsible for testing software, they didn't want to find no problems. They looked into the data that was being used and raised a single bug that some of the latitude and longitude details (of some places of interest) were specified to an unnecessary number of decimal places. A quick update to the data formatting app, the addition of an extra test that no lat/long values had unnecessary precision, and then the regeneration of all the data and the app was ready to ship. Once released, no bugs were reported.

Small apps with little feedback and interaction from the people using them aren't always desirable, but it's good to know (remember) that I can build them with impressive speed.