凌晨零点零零

Each Android application lives in its own security sandbox:  1 the operating system is a muti-user Linux system.  2 the system assign each application a unique Linux user ID.  3 each process has

What is activities？        It is an application component that provides a screen with which users can interact in order to do something.        我理解的activity就是手机程序里面的每一个界面，每一个界面就相当于是一个activity，在每