We have an iphone mhealth platform which has some consumer revenues, one enterprise payer pilot and an academic partnership for rct in patients, we want to start android development soon, because it is 90% of our end user demographic (low income prediabetic patients) what are the important factors to consider as we move to developing iOS/android in tandem. We are doing native Development. We are self funded.
Android commands a large market share, but is also very fragmented. One of the things you'll want to consider when developing for Android beyond 90% of your demographic using Android vs iOS, is that you'll also want to figure out what is most common versions of Android that they are using...
For example, it would be pointless and a waste of time to develop an Android app that only supports 4.3 and up if majority of your demographic are still on 2.X.
Once you have the data you need on what versions of Android are most common versions of Android being used among your user demographics, it'll help you pinpoint what version of Android to target as a "minimum required".
Next you'll want to consider if that minimum version includes the necessary features and APIs you'll need to deliver on your app as well. If not you may have to move the requirements up.
These are things you'll need to consider when developing an app for iOS as well, but much less so as the adoption rate for the latest version of the OS is much higher for iOS than it is for Android (due to a large variety of hardware / OEM restrictions with Android handsets and manufacturers).
Let me please cite a piece of my company's blog article about developing two versions of the same app.
Don’t apply the same UI principles for different platforms. It is always good to have a principle as a foundation and do things according to this principle. This is what our team has done using the principle: “consistent design across all platforms”. We tried to design one mobile app for two different platform (iOS and Android) in the same way. Although it sounds good there were some serious side effects. The process of UI design became a battle between developers of these two platforms. For example, swipe on a cell inside a list is a really easy job for iOS app developers. But for Android developers the implementation of the swipes is quite tricky. Most importantly it is not what users of Android apps are used to. On Android it is supposed that the drop down menu is attached to each cell in the list.
At the same time if you design an app using just standard controls then your users don’t need to learn how to use it. In other words, borrowing UI approaches from built-in apps like calendar, email and notes is a right way to go. However a side effect of such an approach is the same app on different platforms does not look and behave similarly. Therefore a new feature should be designed separately for each platform.
I would add that supporting of old versions of Android (2.2) also will make development a little longer.
Hope this helps.