In today's increasingly digital world, the decision to build an Android app is far from trivial. Selecting an android app developer – the expert artisan who will bring your vision to life – is indeed a significant undertaking. This decision-making process is much akin to a meticulous and intricate dance, where the perfect balance of expertise, experience, and ethos is sought. This article will dive into eight pivotal queries you should make before you take the plunge and hire an Android app developer.

Firstly, we must address the elephant in the room: what is their technical prowess? A developer’s technical aptitude is the cornerstone upon which your app will be built. It's essential to assess their proficiency with Java, the primary language for Android app development, or Kotlin, which is now deemed an official language for Android by Google. Moreover, understanding their experience with Android Software Development Kit (SDK) and Android Studio, the official Android development environment, is vital.

Secondly, their past experience and portfolio demand attention. Be it an individual developer or an organization, a robust portfolio is often a reliable symbol of competence. Prior projects can offer insights into their problem-solving ability and their prowess for design and user experience. An in-depth examination of their previous work may provide a glimpse into their capabilities and their knack to work under various constraints.

Thirdly, delve deeper into their understanding of Material Design. It has been the guiding philosophy of Android design since Google introduced it in 2014. Material Design leans on the principles of physical world and its textures to create a more intuitive and responsive user interface. A developer well-versed in the principles of Material Design can craft visually appealing apps that offer excellent user experiences.

Fourth, you should address the question of scalability. In an ever-evolving landscape, scalability is critical. The developer should be able to demonstrate a clear strategy for building the app in a way that it can handle an increased load in the future. Evaluating their knowledge on Load Balancing and Database Sharding, among others, could be instrumental in validating their approach to scalability.

Fifth, their understanding of the Android ecosystem is crucial. Android, with its fragmentation across various manufacturers and versions, poses unique challenges for developers. The developer's approach to these challenges and their knowledge of the Android ecosystem can often make or break the success of your app.

Sixth, their familiarity with the Agile methodology warrants exploration. Agile development is an iterative approach that promotes a flexible response to changes. It is often preferred in app development due to its ability to adapt to evolving requirements. Their competence in Agile can illuminate their ability to deliver a high-quality product within deadlines.

Seventh, their testing strategy calls for scrutiny. A robust testing regimen is the guardian that stands between your app and catastrophic failures. Whether they opt for Black-box testing, White-box testing, or Grey-box testing, their approach to testing can be a direct reflection of their commitment to quality.

Last but not least, their track record of post-launch support and maintenance matters. The app’s journey doesn't end with its launch. Frequent updates, bug fixes, and user support are critical for its long-term success. Developers' dedication to support and maintenance is a testament to their commitment to your project.

In conclusion, choosing the right Android app developer is not a decision to be taken lightly. It requires a methodical evaluation of several aspects, including technical expertise, past experience, understanding of Material Design, thoughts on scalability, knowledge of the Android ecosystem, familiarity with Agile development, testing strategy, and post-launch support. Each of these elements contributes significantly to ensuring that your Android app project is a resounding success.