本文是介绍Android中的Binder机制。
Binder 是 Android 系统进程间的一种通信机制，官方介绍：
Base class for a remotable object, the core part of a lightweight remote procedure call mechanism defined by
IBinder. This class is an implementation of IBinder that provides standard local implementation of such an object.
远程对象的基类，它是 IBinder 定义的轻量级远程过程调用机制的核心部分。此类是 IBinder 的实现，它提供此类本地对象的标准实现。
本文是介绍Android中的ThreadLocal。
ThreadLocal 是线程局部(本地)变量，也许把它命名为 ThreadLocalVariable 更容易让人理解一些。官方介绍：
This class provides thread-local variables. These variables differ from their normal counterparts in that each thread that accesses one (via its
getorsetmethod) has its own, independently initialized copy of the variable.ThreadLocalinstances are typically private static fields in classes that wish to associate state with a thread (e.g., a user ID or Transaction ID).
本文是介绍Android中的IntentService。
IntentService 是 Android 里的一个封装的抽象类，继承自 Service。官方介绍：
IntentService is a base class for
Services that handle asynchronous requests (expressed asIntents) on demand. Clients send requests throughContext.startService(Intent)calls; the service is started as needed, handles each Intent in turn using a worker thread, and stops itself when it runs out of work.
本文是介绍Android中的HandlerThread。
HandlerThread 是 Android 已封装好的轻量级异步通信类。官方介绍：
A
Threadthat has aLooper. TheLoopercan then be used to createHandlers.Note that just like with a regular
Thread,Thread.start()must still be called.
一个具有 Looper 的线程。该 Looper 可以用来创建 Handler。和使用常规线程一样，Thread.start() 仍必须调用。
本文是介绍Android中的Handler消息机制。
Handler 机制是 Android 中用于线程间通信的一套异步通信机制。官方的介绍是：
A Handler allows you to send and process
Messageand Runnable objects associated with a thread’sMessageQueue. Each Handler instance is associated with a single thread and that thread’s message queue. When you create a new Handler it is bound to aLooper. It will deliver messages and runnables to that Looper’s message queue and execute them on that Looper’s thread.
本文是介绍Android常用的组件之一的Fragment。
Fragment，简称碎片，是 Android最基本，最重要的基础概念之一。Fragment 官方的定义是：
A Fragment represents a behavior or a portion of user interface in an Activity. You can combine multiple fragments in a single activity to build a multi-pane UI and reuse a fragment in multiple activities. You can think of a fragment as a modular section of an activity, which has its own lifecycle, receives its own input events, and which you can add or remove while the activity is running.
本文是介绍Android的四大组件之一的ContentProvider。
ContentProvider 是 Android 中提供的专门用于不同应用间数据交互和共享的组件。它实际上是对SQLiteOpenHelper 的进一步封装，以一个或多个表的形式将数据呈现给外部应用，通过 Uri 映射来选择需要操作数据库中的哪个表，并对表中的数据进行增删改查处理。ContentProvider 其底层使用了 Binder 来完成APP 进程之间的通信，同时使用匿名共享内存来作为共享数据的载体。ContentProvider 支持访问权限管理机制，以控制数据的访问者及访问方式，保证数据访问的安全性。