学习android需要学习的编程知识
从http://source.android.com/source下载的网页
Android开发软件Android Studio
详细显示编译过程
make -j4 showcommands
一些常用的编译目标
Here is a list of different make targets you can use to build different parts of the system: make sdk - build the tools that are part of an SDK (adb, fastboot, etc.) make snod - build the system image from the current software binaries make services make runtime make droid - make droid is the normal build. make all - make everything, whether it is included in the product definition or not make clean - remove all built files (prepare for a new build). Same as rm -rf out// make modules - shows a list of submodules that can be built (List of all LOCAL_MODULE definitions) make - make a specific module (note that this is not the same as directory name. It is the LOCAL_MODULE definition in the Android.mk file) make clean- - clean a specific module make bootimage TARGET_PREBUILT_KERNEL=/path/to/bzImage - create a new boot image with custom bzImage
一些常用的宏和函数
There are some helper macros and functions that are installed when you source envsetup.sh. They are documented at the top of envesetup.sh, but here is information about a few of them: croot - change directory to the top of the tree m - execute 'make' from the top of the tree (even if your current directory is somewhere else) mm - builds all of the modules in the current directory mmm... - build all of the modules in the supplied directories cgrep - grep on all local C/C++ files jgrep - grep on all local Java files resgrep - grep on all local res/*.xml files godir - go to the directory containing a file
介绍Android源码下每个目录的作用
重新编译某个模块
To rebuild only the module which you are changing (ie, the stuff in your current directory), you can usually do this:mm -B
将Android源码导入Android Studio
Android调试工具
1. systrace
(用systrace调试display system:)
用法:systrace这个工具在Android源码目录下的external/chromium-trace/下,用法(使用-h参数可以获得更详细的帮助信息):
- ./systrace.py -e emulator-5554 -l
gfx - Graphics input - Input view - View System webview - WebView wm - Window Manager am - Activity Manager sm - Sync Manager audio - Audio video - Video camera - Camera hal - Hardware Modules app - Application res - Resource Loading dalvik - Dalvik VM rs - RenderScript bionic - Bionic C Library power - Power Management sched - CPU Scheduling irq - IRQ Events freq - CPU Frequency idle - CPU Idle disk - Disk I/O mmc - eMMC commands workq - Kernel Workqueues memreclaim - Kernel Memory Reclaim
- ./systrace.py -e emulator-5554 gfx sched video -t 60 -o "`date +%y-%m-%d-%H-%M-%S`".html
- 那么如何在要调试的代码中加入相应的systrace可以识别的信息呢?
以media/libmedia/AudioTrack.cpp为例:
#define ATRACE_TAG ATRACE_TAG_ALWAYS
// 表示一直会打开,如果是ATRACE_TAG_AUDIO,则需要在systrace中加入audio参数才能看到
#include <utils/Trace.h>
然后在需要调试的函数的入口(以AudioTrack::start)为例:
status_t AudioTrack::start()
{ + ATRACE_NAME("AudioTrack::start"); status_t status = NO_ERROR; AutoMutex lock(mLock); if (mState == STATE_ACTIVE) { 或者status_t AudioTrack::start()
{ + ATRACE_CALL(); status_t status = NO_ERROR; AutoMutex lock(mLock); if (mState == STATE_ACTIVE) {
2. dumpsys
3. pytimechart
4. ftrace 和 trace_cmd
媒体文件重新识别
下面的命令可以让sdcard上的媒体文件重新识别,当使用adb push命令向手机里放入媒体文件后,手机并不能立即识别这个媒体文件,需要重启手机,下面的命令可以不用重启手机。
#! /bin/bashadb shell am broadcast -a android.intent.action.MEDIA_MOUNTED -d file:///mnt/sdcard/
Android示例代码学习
在android源代码的cts目录下有很多示例代码,其中的程序都不是很复杂,值得学习一下。
media相关的: cts/tests/tests/media/src/android/media/cts
graphic相关的: cts/tests/tests/graphics/src/android/graphics/cts
ADB 工具
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