blocks|key|303818|text|绑定器是一种在内核中运行的优化编组方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|303819|关于它的几个链接：|303820|http://www.cubrid.org/blog/dev-platform/binder-communication-mechanism-of-android-processes/+http://lukejin.wordpress.com/2011/03/13/android%25E4%25B8%25AD%25E7%259A%2584binder/|offset|length|303821|entityMap|0|LINK|mutability|MUTABLE|url|http://www.cubrid.org/blog/dev-platform/binder-communication-mechanism-of-android-processes/|1|http://lukejin.wordpress.com/2011/03/13/android%25E4%25B8%25AD%25E7%259A%2584binder/^0|0|0|0|2K|0|2L|20|1|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|T|8|@]|9|@$F|U|G|V|1|W]|$F|X|G|Y|1|Z]]|A|$]]|$1|H|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]|P|$5|K|L|M|A|$N|Q]]]]

Binder is an optimized marshalling method that runs in the kernel.

Couple of links about it:

<a href="http://www.cubrid.org/blog/dev-platform/binder-communication-mechanism-of-android-processes/" rel="nofollow">http://www.cubrid.org/blog/dev-platform/binder-communication-mechanism-of-android-processes/</a>
<a href="http://lukejin.wordpress.com/2011/03/13/android%E4%B8%AD%E7%9A%84binder/" rel="nofollow">http://lukejin.wordpress.com/2011/03/13/android%E4%B8%AD%E7%9A%84binder/</a>

blocks|key|4084334|text|http://marakana.com/s/post/1340/Deep_Dive_Into_Binder_Presentation.htm|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|4084335|此链接提供了有关Binder如何作为架构工作的非常有用的概述，还提供了使用与应用程序开发人员(Intents、Messenger、AIDL)相关的Binder的各个方面的示例代码。|4084336|entityMap|0|LINK|mutability|MUTABLE|url^0|0|1Y|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@$A|N|B|O|1|P]]|C|$]]|$1|D|3|E|5|6|7|Q|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|R|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|4]]]]

<a href="http://marakana.com/s/post/1340/Deep_Dive_Into_Binder_Presentation.htm" rel="nofollow">http://marakana.com/s/post/1340/Deep_Dive_Into_Binder_Presentation.htm</a>

This link provides very useful overview in how Binder works as an architecture, and also provides sample code for utilizing each aspects of Binder that are relevant to app developers (Intents, Messenger, AIDL).

blocks|key|4084396|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4084397|这篇文章说进程交换共享内存中的对象引用|blockquote|4084398|4084399|4084400|4084401|我认为混淆是在绑定器协议和Android的“绑定器”RPC机制之间。就proto而言，它只是被复制进来和拷贝出来的字节。Android平台使用Binder内核驱动程序实现了一种类似OO的RPC机制。这当然会将对象“编组”到字节，然后在另一端将它们解组回一个对象。这可以在Parcel类和Parcelable接口的帮助下完成。|offset|length|style|CODE|4084402|entityMap^0|0|0|0|0|0|3R|6|3Z|A|0^^$0|@$1|2|3|-4|4|5|6|O|7|@]|8|@]|9|$]]|$1|A|3|B|4|C|6|P|7|@]|8|@]|9|$]]|$1|D|3|-4|4|5|6|Q|7|@]|8|@]|9|$]]|$1|E|3|-4|4|5|6|R|7|@]|8|@]|9|$]]|$1|F|3|-4|4|5|6|S|7|@]|8|@]|9|$]]|$1|G|3|H|4|5|6|T|7|@$I|U|J|V|K|L]|$I|W|J|X|K|L]]|8|@]|9|$]]|$1|M|3|-4|4|5|6|Y|7|@]|8|@]|9|$]]]|N|$]]

<blockquote>
 The article says that the processes swap the object references in the
 shared memory
</blockquote>

Binder does not use shared memory (ashmem nor pmem). It uses a kernel driver with a fixed-size buffer. Data is copied into and out of the kernel is a secure manner. Maybe the article is using "shared memory" loosely.

I think the confusion is between the Binder protocol, and Android's "Binder" RPC mechanism. As far as the proto is concerned, it's just bytes being copied in and out. The Android platform implements an OO-like RPC mechanism using the Binder kernel driver. This does of course "marshall" objects to bytes and unmarshalls them on the other side back to an object. This is done with help of the <code>Parcel</code> class and <code>Parcelable</code> interface.

blocks|key|753145|text|一个古老的问题，但值得一个最新的答案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|753146|Binder工具使用了句柄，这使得处理对象变得更快、更容易。在某些情况下，不必封送整个对象，只返回对象句柄，之后可以通过其方法对其进行操作。这意味着对象的大部分(可能非常大)根本不需要进行封送处理-节省了CPU和开销。|753147|例如，考虑屏幕捕获是如何执行的。(q.v.屏幕帽实用程序的源代码)，或者(作为另一个示例)+MediaPlayer如何工作。调用“create”方法|753148|+++virtual+sp<IMediaPlayer>+create(const+sp<IMediaPlayerClient>&+client,
++++++++++++audio_session_t+audioSessionId+=+AUDIO_SESSION_ALLOCATE)+

flame:/+$+service+call+media.player+1
Result:+Parcel(
++0x00000000:+73682a85+00000113+00000002+00000000+'.*hs............'
++0x00000010:+00000000+00000000+0000000c++++++++++'............++++'|code-block|syntax|javascript|753149|'*hs‘(实际上是*sh)是一个绑定器强句柄，这意味着与其关联的描述符(在本例中为'2')可以在后续的直接调用中使用，以调用IMediaPlayer功能。如果随后针对其接口探测返回的描述符，则可以证明这一点：|753150|flame:/+$+/data/local/tmp/bdsm+call+media.player+1+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Got+handle+to+android.media.IMediaPlayerService
Object+0+(desc+2)+is+a+handle+to+android.media.IMediaPlayer|753151|这和预期的一样(sp)。这意味着现在可以直接调用IMediaPlayer实例的方法。|753152|ashmem将匿名SHared+MEMory映射到文件描述符上，然后通过绑定器将该文件描述符从进程A移动到B(绑定器可以像UN*X域套接字一样移动文件描述符)。|753153|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|X|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|H|7|Z|8|@]|9|@]|A|$I|J]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|11|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

Ancient question, but worthy of an up-to-date answer:
The Binder facility makes use of handles, which make it much faster and easier to work with objects. Rather than necessarily marshal the entire object, in some cases only the object handle is returned, after which it can be manipulated through its methods. That means that the bulk of the object (which can be very big) need not be marshaled at all - saving both in CPU and overhead.
As an example, consider how a screen capture is performed. (q.v. source of screen cap utility), or (as another example) how MediaPlayer works. Binder will acquire a handle to the remote object, but the object doesn't actually go &quot;over the wire&quot;. Calling the 'create' method
<pre><code> virtual sp&lt;IMediaPlayer&gt; create(const sp&lt;IMediaPlayerClient&gt;&amp; client,
 audio_session_t audioSessionId = AUDIO_SESSION_ALLOCATE) 

flame:/ $ service call media.player 1
Result: Parcel(
 0x00000000: 73682a85 00000113 00000002 00000000 '.*hs............'
 0x00000010: 00000000 00000000 0000000c '............ '
</code></pre>
That '*hs' (actually *sh), is a Binder STRONG HANDLE, which means that the descriptor associated with it (in this case, '2') can then be used in subsequent, direct calls, to invoke the IMediaPlayer functionality. This can be demonstrated if that returned descriptor is then probed for its interface:
<pre><code>flame:/ $ /data/local/tmp/bdsm call media.player 1 
Got handle to android.media.IMediaPlayerService
Object 0 (desc 2) is a handle to android.media.IMediaPlayer
</code></pre>
which is as expected (sp). Meaning that now the IMediaPlayer instance's method can be invoked directly.
Btw, while it's true that Binder doesn't use shared memory, the above reply on ashmem isn't exactly accurate. ashmem maps the Anonymous SHared MEMory onto a file descriptor, and then that file descriptor gets moved from process A to B over Binder (which can move file descriptors just as UN*X domain sockets do). Also, Parcels can hold these *SHs (strong handles) whenever you see an IBinderToken item &quot;marshaled&quot; to it.

I read an article about android's binder. The article says that the processes swap the object references in the shared memory and that it is more efficient than marshalling and unmarshalling...But in fact there is a marshalling and unmarshalling in the IPC-machanism or not?? I'm a bit confused...

Can anyone explain the binder-mechanism or link to a detailed article?

Android - Binder

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我读了一篇关于android活页夹的文章。文章说，进程交换共享内存中的对象引用，并且它比编组和unmarshalling...But更有效。事实上，在进程间通信机制中存在编组和解组机制？我有点困惑..。有人能解释一下活页夹的机制或链接到详细的文章吗？

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