ZooKeeper ZooKeeper: A Distributed Coordination Service for Distributed Applications Design Goals Data model and the hierarchical namespace Nodes and ephemeral nodes Conditional updates and watches Guarantees Simple API Implementation Uses Performanc…
1.Activity是通过startActivity()开始的,结束后不反回任何结果,而用startActivityForResult(Intent intent, int resquestCode)方法启动Activity,特定的结果会作为参数返回给Activity类的void onActivityResult(intrequest requestCode, int resultCode,Intent data)回调方法. 2.Activity的生命周期就是调用onStart()到调用onSt…