After nearly a year of hard work, the Home Control Flex application has finally reached a new release point. There have been major improvements around the use of Xamarin Forms and the use of mobile features. There were major changes around framework dependencies and utilization of navigation pages.
The major problems in the previous version was poor usage of navigation pages, dependencies on old frameworks, and lack of sharing of global resources. Adding all of these failures together resulted in an unstable application that crashed on multiple pages. Fixes to those crashes were a slow roll out of shims and hacks to keep the previous decisions working.
The largest problem was the poor usage of navigation pages. For some reason, to implement a tabbed page where the tabs were at the bottom on Android, the previous developers decided to use a ContentPage, and make the tab pages within the ContentPage ContentViews and swap those views out whenever a tab was changed. This caused almost every major problem that could not be resolved in the app moving forward. To fix it, the BottomNavigationBarXF Nuget packages was used. The base renderer was overridden to implement some custom functionality but overall it was a clean integration or at least as clean as such a big overhaul to the navigation system can handle.
Since the pages were being swapped out whenever a tab was changed, the previous developers mush have decided that instead of needing navigation pages, they would just continue to change the view out and have their own navigation stack. Without using NavigationPage within their app, the page lifecycle was completely off and the were object disposed exceptions that were being thrown by the Forms framework due to the fact that the views lifecycle was not correctly managed. Xamarin Forms couldn’t track whether a view was to be reused or not and would collect on disappeared views that were going to come back later. Once NavigationPage was used this was no longer a problem.
When I inherited the app there were multiple frameworks being used in the application. It seemed to have a javascript approach where a framework may be brought in for some partial functionality or even a single method. Xamarin Forms Labs was the biggest offender when I inherited the app. The previous developers had referenced it to use it for one control and two converters. Once it was removed, the application was much more light weight on disk. At the time it was removed there was no noticeable performance gain but that was most likely due to the lack of utilization within the app and the fact that I had only been with the app for a month.
This app was riddled with copy and paste code reuse. Every page shared the same Style declaration with the same name (which was the style for that page). Every page had a declaration of a Converter for inverting a boolean. All these “shared” resources were moved to the App.XAML for reuse by every page within the application.
After fixing the above issues, changing a variety of pages within the app, and adding a load of new features, the app should finally be a stable release with market effects that was expected out of its first release. I hope to continue to improve on the line of applications from Telular including this app.
