The difference between oncreate and onrestoreinstancestate recovery data of activity

1、 Preface

Today, I inadvertently brushed a so-called Android Interview classic article , Curiosity drove me to take a look . And then you see ActivityonCreate 、onRestoreInstanceState The difference between restoring data , So I checked the information systematically , And then there's this blog post .

Reference material ：《Android Kernel analysis 》、android-26 Of Activity and ActivityThread Source code .

2、ActivityThread Briefly explain

ActivityThread Is not a Thread object , Just one. “ Ordinary ” Of Java object .ActivityThread The thread of the object is UI Thread or main thread . all APK There is only one program ActivityThread object . This class provides a static main Method ,：