How to start an application

The startup process of the entire application needs to perform many steps, but as a whole, it is mainly divided into the following five stages:
       1. Step1 - Step 11: Launcher notifies ActivityManagerService through the Binder inter-process communication mechanism that it wants to start an Activity;
       2. Step 12 - Step 16: ActivityManagerService notifies Launcher to enter the Paused state through the Binder inter-process communication mechanism;
       3. Step 17 - Step 24: Launcher notifies ActivityManagerService through the Binder inter-process communication mechanism that it is ready to enter the Paused state, so ActivityManagerService creates a new
       4. Step 25 - Step 27: ActivityThread passes a Binder object of ApplicationThread type to ActivityManagerService through the Binder inter-process communication mechanism, so that In the future, ActivityManagerService can communicate with it through this Binder object;
       5. Step 28 - Step 35: ActivityManagerService notifies ActivityThread through the Binder inter-process communication mechanism, and now everything is ready, it can actually start the Activity.