2. Development Fundamentals

This chapter studies the basic composition of a mobile app and exposes intricacies associated with its development. A mobile app is typically composed of a graphical user interface, provides for local storage of data, and supports communication with the peers as well as connectivity to the enterprise over suitable networks. Although such functional subsystems or components are expected in most desktop apps as well, frameworks and libraries created for the smartphones distinguishably enable mobile apps leverage the full potential of the available resources, peripherals, and accessories while helping mask any underlying deficiencies and constraints. GUI frameworks developed for smartphones, for example, are aimed at mitigating constraints such as the small screen size and missing mouse or keyboard, on the usability of mobile apps by enabling mobile apps leverage touch screen to its maximum potential through rich touch gestures recognition capabilities and providing libraries full of ready-to-use novel UI (user interaction) controls deemed to be highly conducive to mobile usage. Section 2.1 highlights the flexibility with which the user interaction, including facilitation of inter-/intra-application navigation, through widget libraries available on mobile platforms, could be incorporated. Section 2.2 furthers this discussion by putting the focus on data storage alternatives that are supported on the smartphones to address the data storage needs of mobile apps. Again, while these data storage capabilities are similar to those on desktops, implications of the choice of internal versus the external storage on the security and performance of the mobile apps is the underlying motivation for the study. On the networking front, smartphones come equipped with much wider selection of network interfaces as compared to desktops. These include cellular, WiFi (Wireless Fidelity), Bluetooth, and NFC (near-field communication) interfaces. As opposed to desktops, where these interfaces are generally plugged in mostly through USB ports, smartphones include native and seamless access to variety of networks via these network interfaces. Section 2.3 identifies key network APIs and demonstrates their utilizing in facilitating basic communication needs of a mobile app. Section 2.4 revisits concurrency with the purpose of examining the extent of support from the smartphone environments as these are often either stacked on top of other operating systems or are their modified versions. Support for threads, processes, and services is therefore verified so that these system utilities could be relied upon to mask resource constraints and I/O (input/output) latencies experienced by smartphone apps. Availability of GPS for location sensing along with a large set of motion and environment sensors on smartphones distinguishes them further from desktops. Onboarding of these sensors on smartphone platforms has led to the emergence of new classes of applications and services that were not conceivable on tethered desktops. Section 2.5 demonstrates use of location and sensor APIs so that the data from these sensors could be acquired and fused effectively to complement mobile apps with a location, presence, and environmental context and further enhance end user’s quality of experience.