14 Feb 2015
OS: Android 4.4
Kernel: 3.10.28
这里所谓的修改kernel version string并不是真的修改linux的版本号，因为那样会导致非常多的问题（比如一些驱动会不能用，等等）。所以这里修改的仅仅是/proc系统下的version，而从/proc/version中读取kernel version string是一个通常的做法，所以只需要修改这个就可以了。
kernel/fs/proc/version.c
static int version_proc_show(struct seq_file *m, void *v)
{
seq_printf(m, linux_proc_banner,
utsname()->sysname,
utsname()->release,
utsname()->version);
return 0;
}
seq_printf和printf的功能很类似，可以输出经格式化的字符串。这里的linux_proc_banner参数实际上是一个格式化字符串，它的定义在文件kernel/init/version.c中：
const char linux_proc_banner[] =
"%s version %s"
" (" LINUX_COMPILE_BY "@" LINUX_COMPILE_HOST ")"
" (" LINUX_COMPILER ") %s\n";
所以很明显你可以通过修改上面2个文件来定制你自己的version string.
接下来看看Android的setttings中是如何来读取kernel version的：
packages/apps/Settings/src/com/android/settings/DeviceInfoSettings.java
public static String getFormattedKernelVersion() {
try {
return formatKernelVersion(readLine(FILENAME_PROC_VERSION));
} catch (IOException e) {
Log.e(LOG_TAG,
"IO Exception when getting kernel version for Device Info screen",
e);
return "Unavailable";
}
}
我们看到Android并不是直接返回从/proc/version中读到的内容，而是经过了formatKernelVersion()方法的处理。否则会返回Unavailable。看一下formatKernelVersion()这个方法：
public static String formatKernelVersion(String rawKernelVersion) {
// Example (see tests for more):
// Linux version 3.0.31-g6fb96c9 ([email protected]) \
// (gcc version 4.6.x-xxx 20120106 (prerelease) (GCC) ) #1 SMP PREEMPT \
// Thu Jun 28 11:02:39 PDT 2012
final String PROC_VERSION_REGEX =
"Linux version (\\S+) " + /* group 1: "3.0.31-g6fb96c9" */
"\\((\\S+?)\\) " + /* group 2: "[email protected]" (kernel builder) */
"(?:\\(gcc.+? \\)) " + /* ignore: GCC version information */
"(#\\d+) " + /* group 3: "#1" */
"(?:.*?)?" + /* ignore: optional SMP, PREEMPT, and any CONFIG_FLAGS */
"((Sun|Mon|Tue|Wed|Thu|Fri|Sat).+)"; /* group 4: "Thu Jun 28 11:02:39 PDT 2012" */
Matcher m = Pattern.compile(PROC_VERSION_REGEX).matcher(rawKernelVersion);
if (!m.matches()) {
Log.e(LOG_TAG, "Regex did not match on /proc/version: " + rawKernelVersion);
return "Unavailable";
} else if (m.groupCount() < 4) {
Log.e(LOG_TAG, "Regex match on /proc/version only returned " + m.groupCount()
+ " groups");
return "Unavailable";
}
return m.group(1) + "\n" + // 3.0.31-g6fb96c9
m.group(2) + " " + m.group(3) + "\n" + // [email protected] #1
m.group(4); // Thu Jun 28 11:02:39 PDT 2012
}
呵呵，Android系统对version string做了正则匹配，所以我们不能随意修改version string,必须要保证这里的正则表达式和上一步中修改的version string能正确匹配，否则就会是unavailable.
06 Feb 2015
Android OS: 4.4.4
Sometimes, you want to change the default MTP/PTP name of your android device.
If you have android source, it’s very easy.
First open the source file:
frameworks/base/media/java/android/mtp/MtpDatabase.java, Line:799(in my source), or you can search the function getDeviceProperty
private int getDeviceProperty(int property, long[] outIntValue, char[] outStringValue) {
switch (property) {
case MtpConstants.DEVICE_PROPERTY_SYNCHRONIZATION_PARTNER:
case MtpConstants.DEVICE_PROPERTY_DEVICE_FRIENDLY_NAME:
// writable string properties kept in shared preferences
String value = mDeviceProperties.getString(Integer.toString(property), "");
int length = value.length();
if (length > 255) {
length = 255;
}
value.getChars(0, length, outStringValue, 0);
outStringValue[length] = 0;
return MtpConstants.RESPONSE_OK;
case MtpConstants.DEVICE_PROPERTY_IMAGE_SIZE:
// use screen size as max image size
Display display = ((WindowManager)mContext.getSystemService(
Context.WINDOW_SERVICE)).getDefaultDisplay();
int width = display.getMaximumSizeDimension();
int height = display.getMaximumSizeDimension();
String imageSize = Integer.toString(width) + "x" + Integer.toString(height);
imageSize.getChars(0, imageSize.length(), outStringValue, 0);
outStringValue[imageSize.length()] = 0;
return MtpConstants.RESPONSE_OK;
default:
return MtpConstants.RESPONSE_DEVICE_PROP_NOT_SUPPORTED;
}
}
Obviously, the outStringValue returned from DEVICE_PROPERTY_DEVICE_FRIENDLY_NAME case section is the MTP name, so you can change the value whatever you want.
Then open the source file:
frameworks/av/media/mtp/MtpServer.cpp, Line:422(in my source), or you can search the function doGetDevInfo
MtpResponseCode MtpServer::doGetDeviceInfo() {
MtpStringBuffer string;
char prop_value[PROPERTY_VALUE_MAX];
MtpObjectFormatList* playbackFormats = mDatabase->getSupportedPlaybackFormats();
MtpObjectFormatList* captureFormats = mDatabase->getSupportedCaptureFormats();
MtpDevicePropertyList* deviceProperties = mDatabase->getSupportedDeviceProperties();
// fill in device info
mData.putUInt16(MTP_STANDARD_VERSION);
if (mPtp) {
mData.putUInt32(0);
} else {
// MTP Vendor Extension ID
mData.putUInt32(6);
}
mData.putUInt16(MTP_STANDARD_VERSION);
if (mPtp) {
// no extensions
string.set("");
} else {
// MTP extensions
string.set("microsoft.com: 1.0; android.com: 1.0;");
}
mData.putString(string); // MTP Extensions
mData.putUInt16(0); //Functional Mode
mData.putAUInt16(kSupportedOperationCodes,
sizeof(kSupportedOperationCodes) / sizeof(uint16_t)); // Operations Supported
mData.putAUInt16(kSupportedEventCodes,
sizeof(kSupportedEventCodes) / sizeof(uint16_t)); // Events Supported
mData.putAUInt16(deviceProperties); // Device Properties Supported
mData.putAUInt16(captureFormats); // Capture Formats
mData.putAUInt16(playbackFormats); // Playback Formats
property_get("ro.product.manufacturer", prop_value, "unknown manufacturer");
string.set(prop_value);
mData.putString(string); // Manufacturer
property_get("ro.product.model", prop_value, "MTP Device");
string.set(prop_value);
mData.putString(string); // Model
string.set("1.0");
mData.putString(string); // Device Version
property_get("ro.serialno", prop_value, "????????");
string.set(prop_value);
mData.putString(string); // Serial Number
delete playbackFormats;
delete captureFormats;
delete deviceProperties;
return MTP_RESPONSE_OK;
}
You need to change the Model String which read from the system ro.product.model property by default.
That’s all.
05 Feb 2015
修改后的文件名格式：0001, 0002, …. 0100 …. 0999
Params: $1: 文件所在文件夹
$2: 目标文件的起始编号（宽度+1位）， 如：宽度为4位时需要附加一个宽度位（10001）
#!/bin/bash
cd $1
declare -i count
count=$2
ls * | while read file;
do
mv "$file" ${count:1}.jpg
count=$((count+1))
done
#下面的代码片段不能处理文件名中的空格，当然也可以使用IFS来解决这个问题
#for file in `ls`
#do
# mv $file ${count:1}.jpg
# count=$((count+1))
#done
05 Feb 2015
HOST: Ubuntu 14.04
OS: Android 4.4
Kernel: 3.10.28
Plugin Android Device and run the command:
lsusb -v
I find my device information like this:
default Manufacturer and Product name
Then go to Settings —-> Storage —-> USB computer connection, Select MTP or PTP. Ubuntu will popup a window like this:
default Manufacturer and Product name
That confusion. So I want to change the default manufacturer and product name.
first open the file kernel/drivers/usb/gadget/android.c
Find the line: (in my source file it’s at line 3309)
/* Default strings - should be updated by userspace */
strlcpy(manufacturer_string, "Android",
sizeof(manufacturer_string) - 1);
strlcpy(product_string, "Android", sizeof(product_string) - 1);
Obviously, you just need to change the string “Android” here.
Finally build boot image, flash it. That’s all .
PS:
The name of title and left side column is read from Manufacturer and Product String. If you want to change the name of MTP and PTP, you can read this article.
05 Feb 2015
准备动画图片
把制作好的动画帧图片按播放顺序命名，如 0001.png 0002.png … 0098.png 0099.png，命名可以不连续但是先后顺序一定要正确，Android将以数值升序播放。Tip:如何在Linux下批量重命名
创建父文件夹并命名为animation。
创建子文件夹并命名为part0。
把命名好的图片放到part0中。（PS：我分别测试了PNG和JPG格式的图片，Android都可以正常播放）接着在父文件夹中创建文件desc.txt，这个文件将控制Android如何播放动画。
看一下这个文件的:
800 1280 24
p 0 1 part0
第一行: 800 1280是图片宽高，一般跟手机屏幕的宽高一致。 24指的是播放帧率(帧/s)。
第二行：p标志一条播放规则。0 循环播放本文件中所有图片的次数，值0表示无限循环直到进入系统。1 播放相邻两帧图片之间的间隔时间。part0 对应图片的文件夹。
你可以用相同的方法建立多条播放规则，需要注意的是无限循环规则应该放到最后一条。 如：
800 1280 24
p 1 1 part0
p 1 0 part1
p 0 0 part2
打包
Android bootanimation不支持经过压缩的包，记住一定要只打包不压缩。
cd animation
zip -r -0 animation.zip part0 part1 desc.txt
修改文件权限
这一步只在定制android源码时需要，直接push到机器的话可以跳过这步。
chmod +x bootanimation.zip
安装
adb push bootanimation.zip /system/media/
Finally, Reboot device.