Activity 的生命周期和启动模式

ActivityThread#performLaunchActivity - oncreate、onstart、onrestoreinstancestate、onpostCreate(Called when activity start-up is complete (after {@link #onStart} and {@link #onRestoreInstanceState} have been called). Applications will generally not implement this method; it is intended for system classes to do final initialization after application code has run.)

Activity 启动过程中最重要的几个类：Instrumentation、ActivityThread、Activity