onpostcreat()

protected void onPostCreate (Bundle savedInstanceState)

Added in API level 1
Called when activity start-up is complete (after onStart() and onRestoreInstanceState(Bundle) 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.

Derived classes must call through to the super class‘s implementation of this method. If they do not, an exception will be thrown.

Parameters
savedInstanceState If the activity is being re-initialized after previously being shut down then this Bundle contains the data it most recently supplied in onSaveInstanceState(Bundle). Note: Otherwise it is null.
See Also
onCreate(Bundle)

官方文档的解释

一个回调方法吧