(This book is very useful. This is by no means a boring source code analysis. It is a good book to deeply understand the working mechanism and implementation principle of Android. Why is it practical? Because its ultimate goal is not to stay in the source code analysis, but to help developers solve practical problems, the analysis and explanation of all knowledge points are based on the actual needs of developers. Compared with the general source code analysis book, this book has a bit more humor in language and is more vivid and easy to understand. More importantly, the analysis in this book is very in-depth, exploring the nature of Android related functional modules.)