(How can the Essentials of Android Development write about the use of Android that is close to the Android design concept and can run more efficiently and reliably? It is one of the most important ways to understand the underlying implementation details through Android source code! However, the Android system is too large, the source code implementation is messy, and the technical threshold and time cost of learning are high. Is there a way to help developers understand the use and development of Android in depth, without being entangled by many low-level implementation details, and quickly master the knowledge needed to write high-quality Android applications? Android Development Essentials gives a perfect answer to this question! It extracts the "essence" and "key" of Android development from the complex source code of Android, strips out many trivial underlying implementation details, and carries out a high degree of synthesis and summary. It can not only help developers understand the design concept of the entire Android system from a micro perspective, but also help developers grasp the principles of core knowledge points from a micro perspective, and then write high-quality Android applications.)