Google MADA protocol is a mobile application publishing protocol.
The full name is Mobile Application Distribution Agreement, which is suitable for hardware manufacturers who want to pre-install Google's Android applications such as YouTube or Gmail on their devices. According to MADA, hardware manufacturers who wish to pre-install a Google application must pre-install all applications.
Extended information
Android is an open source system, but Google services are not open source, and pre-installation requires authorization from Google. MADA limits how manufacturers can pre-install Google applications. At the same time, Google is adding more and more Android code to non-open source Google services. If the Android machine sold is intended to use any Google services, it must be pre-installed with a full set of Google applications.
Since Google does not open any services related to Google accounts in China, MADA is naturally not valid for Chinese manufacturers. Basically, the Bank of China mobile phones do not come with Google services, and a few of the Bank of China mobile phones with Google services pre-installed are not authorized by Google.
Android's system architecture, like its operating system, adopts a layered architecture. From the architecture diagram, Android is divided into four layers. From high level to low level, they are the application layer, application framework layer, system runtime layer and Linux kernel layer.
Applications:
Android will be released with a series of core application packages, which include clients, SMS short message programs, calendars, maps, browsers, and contacts. Management programs, etc. All applications are written using JAVA language.
Application Framework:
Developers also have full access to the API framework used by core applications. The application's architectural design simplifies the reuse of components; any application can publish its function blocks and any other application can use the published function blocks (but must comply with the framework's security). Likewise, the application reuse mechanism also allows users to easily replace program components.