Android

Android-x86 基于2.2版本的froyo x86打包下载zip

1 year ago

Android-x86 使用repo sync直接从服务器建立和更新git库非常的不稳定，链接经常中断，搞了一星期也没有下载好。后来在服务器上直接下载，很快就同步好了，可见主要问题还是网络的国际出口不稳定造成的。然后在服务器端打成zip包下载，就快多了。

由于Android-x86.org组织不提供类似的下载，我就共享一下我制作好的zip包，sync日期是2010年11月28日。

下载包5G左右。

~~地址： http://zhuwenhao.com/download/android-froyo.zip~~

由于服务器资源有限，本下载不保证长期提供。

Update: 本文件已删除,请下载下面的较新链接,硬盘没空间了,欢迎赞助

另请注意，以下文件有问题，会编译不通过。

frameworks/base/opengl/tests/gl_jni/jni/gl_code.cpp

解决的办法是在该文件的末尾加一个空行。如果先修改一下，就免得编译两遍了。

！更新！

2011年1月4日 repo sync 操作，重新打包。下载：

android-froyo-2011-01-04.zip

这个版本我没有编译测试过，有问题请留言告知大家，谢谢。

Android编译C代码时链接其他库文件的方法(附make file详解手册)

1 year ago

by 朱文昊 Albert Zhu in Android

Android的内核基本就是Linux。在Android-x86的代码基础上，可以编译自己的Android系统。

常常需要在自己的C代码里链接第三方提供的库文件，例如以.a文件提供。此时需要修改Android.mk文件来加进需要连接的库。LOCAL_LDLIBS不是做这个的，一个可行的方法是使用LOCAL_LDFLAGS通知编译器。例如

LOCAL_LDFLAGS -L$(LOCAL_PATH) -lxxxx

其中xxxx是被链接模块的名字，不含后缀和前缀lib

注意-L后面使用相对路径似乎不行。

后面附上来自http://android.git.kernel.org/?p=platform/build.git;a=blob_plain;f=core/build-system.html

的Android系统makefile的文档，因为很难准确google到，转载记录一下。Android的资料水都太大了。

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AudioRecord的使用例程

1 year ago

by 朱文昊 Albert Zhu in Android, 随笔

Android 1.5 has a AudioRecord class that can record raw audio. Here is a tutorial with source code on how to do it. Tried it out and its working. The program creates a test.raw in the sdcard.

http://www.anddev.org/viewtopic.php?p=22820

This is from that link:

Okay. It works now. It turns out that the audio device stopped responding after the Music application, for lack of a more precise description, wonked-out; a reboot restored the audio device to a functional state.

After playing with the the code I have,

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Android上录音的三种接口

1 year ago

by 朱文昊 Albert Zhu in Android

THE THREE MUSKETEERS OF AUDIO RECORDING FROM ANDROID

Let me introduce you to the three musketeers of audio recording from android os. They are the three ways for recording audio in android. They are

1) Mediarecorder

2) Audiorecord

3) Audiorecord :- native interface

http://developer.android.com/reference/android/media/MediaRecorder.html

USAGE :- http://developer.android.com/guide/topics/media/index.html

Mediarecorder does what it says. It records media. It can be used to record audio from Mic to a file on the sdcard. The recorded audio would be in MPEG4, RAW AMR or 3GP.

Please note : The example provided along with the documentation does not work. However, there are lots of help on the internet to get the mediarecorder running.

pros :

easy to use
records audio in compressed format
can be used to record voice calls – both uplink and downlink
can be used to record speech recognition

cons

can not access the audio buffers
difficult to process the recorded audio as it would be compresses format.
can not change the sampling rate
very little or no control of how the recording happens

2)

API Documentation :- http://developer.android.com/reference/android/media/AudioRecord.html

USAGE :- http://hashspeaks.wordpress.com/2009/06/18/audiorecord-part-4/

Audiorecord API is google’s official solution to overcome the limitations of mediarecorder.Audio can be recorded into buffers for post processing. Audiorecord is a java way to record audio and process audio.

pros:

records audio as MONO or STEREO
various properties for audiorecording like sample size, sample rate, buffersize can be set.
the recorded audio is provided in buffers.

cons:

difficult to handle buffers.Unless you know what you are doing. you will lose samples.

3)

A LITTLE BIT HELP : http://hashspeaks.wordpress.com/2009/04/18/audiorecord-in-android-part-2/

USAGE :- ( Coming soon… how to build using NDK, sample code and how to use this API )

There is also a native interface – audiorecord that can be used for recording audio. The native interface provides API that can be invoked from c/c++ libraries. These librarires can then be called from Java activity via JNI. Programs using the interface can be compiled with the NDK and used in android applications via JNI.

pros:

provides a c/c++ interface to recording
the processing is more efficient when done in c/c++ using this API

cos:

no documentation is available for this interface
google does not official support this interface.
This interface could be removed from future releases without further notification. But has remained for over an year now.

原文地址：http://mobware4u.com/tutorials/android-audio-recording