Android apps are bits of software that run on the Android operating system. They can be downloaded on Android tablets, TVs, and phones. They're excellent at using the touchscreen, camera and GPS features of the device. Having lots of apps installed on an Android phone however, could affect the life of batteries and performance.
Developing Android apps requires a deep understanding of the Android platform, including its design principles and frameworks. It also requires an appropriate app architecture that separates UIand OS-related code into components that have shared responsibilities. The system can activate these components asynchronously through an asynchronous broadcast mechanism that is triggered by desires.
Java is the preferred language for Android development, although Kotlin has gained popularity in recent years. Both are supported by the Android SDK. A large developer community is online to help those who are new to the language and troubleshoot problems.
The Android OS is divided into layers. The application layer contains the standard apps that come with the OS, and any other proprietary apps that are included with specific devices, for example, the music player or phone dialer. The Android app layer also includes custom firmwares, like CyanogenMod or OMFGB. They can be installed to customize the functionality of specific devices.
Another reason that stops certain apps from functioning is compatibility. If an app was designed for the US but is not compatible with your European device it will not work and will be listed in the Play Store as "incompatible".