19 Apr 2015
Viewgroup.addView()有5个重载方法：
void addView(View child, int index, ViewGroup.LayoutParams params)
void addView(View child, ViewGroup.LayoutParams params)
void addView(View child, int index)
void addView(View child)
void addView(View child, int width, int height)
如果需要想重写addView()实际只需要重写**addView(View child, int index, ViewGroup.LayoutParams params)**即可。
看一下addView的源码：
public void addView(View child) {
addView(child, -1);
}
public void addView(View child, int index) {
LayoutParams params = child.getLayoutParams();
if (params == null) {
params = generateDefaultLayoutParams();
if (params == null) {
throw new IllegalArgumentException("generateDefaultLayoutParams() cannot return null");
}
}
addView(child, index, params);
}
public void addView(View child, int width, int height) {
final LayoutParams params = generateDefaultLayoutParams();
params.width = width;
params.height = height;
addView(child, -1, params);
}
public void addView(View child, LayoutParams params) {
addView(child, -1, params);
}
/**
* Adds a child view with the specified layout parameters.
*
* @param child the child view to add
* @param index the position at which to add the child
* @param params the layout parameters to set on the child
*/
public void addView(View child, int index, LayoutParams params) {
// addViewInner() will call child.requestLayout() when setting the new LayoutParams
// therefore, we call requestLayout() on ourselves before, so that the child's request
// will be blocked at our level
requestLayout();
invalidate();
addViewInner(child, index, params, false);
}
18 Apr 2015
func someFunctionThatTakesAClosure(closure: () -> () ) {
}
Not use trailing closure
someFunctionThatTakesAClosure({
})
Use trailing closure
someFunctionThatTakesAClosure() {
}
Example
let digitNames = [
0: "Zero", 1: "One", 2: "two", 3: "Three", 4: "Foure",
5: "Five", 6: "Six", 7: "Seven", 8: "Eight", 9: "Nine"
]
let numbers = [16, 58, 510]
let strings = numbers.map{
(var number)->String in
var output = ""
while number > 0 {
output = digitNames[number % 10]! + output
number /= 10
}
return output
}
println(strings)
ref: The Swift Programming Language
16 Apr 2015
好吧，swift这回要逆天了
let yetAnotherPoint = (1, -1)
switch yetAnotherPoint {
case let(x, y) where x == y:
println("(\(x), \(y)) is on the line x == y")
case let(x, y) where x == -y:
println("(\(x), \(y)) is on the line x == -y")
case let(x, y):
println("(\(x), \(y)) is just some arbitary point")
}
ref: The Swift Programming Language
10 Apr 2015
OTA升级脚本build/tools/releasetoolsrecovery-resource.dat
# Recovery is generated as a patch using both the boot image
# (which contains the same linux kernel as recovery) and the file
# /system/etc/recovery-resource.dat (which contains all the images
# used in the recovery UI) as sources. This lets us minimize the
# size of the patch, which must be included in every OTA package.
#
# For older builds where recovery-resource.dat is not present, we
# use only the boot image as the source. ref: build/tools/releasetools/ota_from_target_files
source of imgdiff and bsdiffbootable/recovery/applypatch
Android端的升级脚本两步策略中的第二步，升级重启后执行的脚本（包括建立软链接和权限设置）。
META-INF/com/google/android/updater-script
imgdiff的参数
imgdiff是android提供的用来生成binary patch的工具，android同时还提供了另一个binary patch工具是bsdiff。
usage: -z <src-img> <tgt-img> <patch-file>
-z: 输入文件是否是ZIP格式
-b: 额外的二进制文件，在OTA中，这个文件就是recovery-resource.dat
imgdiff和bsdiff的区别
看下下面这段摘自imgdiff.c的说明就明白了：
- This program(imgdiff) constructs binary patches for images -- such as boot.img
- and recovery.img -- that consist primarily of large chunks of gzipped
- data interspersed with uncompressed data. Doing a naive bsdiff of
- these files is not useful because small changes in the data lead to
- large changes in the compressed bitstream; bsdiff patches of gzipped
- data are typically as large as the data itself
生成全包和差分包生成全包命令
生成全包命令
ota_from_target_files -f 0 -d "MMC" -p out/host/linux-x86/ -k build/target/product/security/testkey -v product-target_files-eng.hostname.zip ~/tmp/full_OTA.zip
生成差分包命令
ota_from_target_files -f 0 -d "MMC" -p out/host/linux-x86 -k build/target/product/security/testkey -v -i product-target_files-eng-old.host.zip product-target_files-eng-new.host.zip ~/tmp/increment_OTA.zip
相关的代码调用
ota_from_target_files中
if OPTIONS.incremental_source is None:
WriteFullOTAPackage(input_zip, output_zip, OPTIONS.fota)
if OPTIONS.package_key is None:
OPTIONS.package_key = OPTIONS.info_dict.get(
"default_system_dev_certificate",
"build/target/product/security/testkey")
else:
print "unzipping source target-files..."
OPTIONS.source_tmp, source_zip = common.UnzipTemp(OPTIONS.incremental_source)
OPTIONS.target_info_dict = OPTIONS.info_dict
OPTIONS.source_info_dict = common.LoadInfoDict(source_zip, OPTIONS.device_type)
if OPTIONS.package_key is None:
OPTIONS.package_key = OPTIONS.source_info_dict.get(
"default_system_dev_certificate",
"build/target/product/security/testkey")
if OPTIONS.verbose:
print "--- source info ---"
common.DumpInfoDict(OPTIONS.source_info_dict)
WriteIncrementalOTAPackage(input_zip, source_zip, output_zip, OPTIONS.fota)
生成OTA步骤
- unzip
- imgdiff / bsdiff
- zip
- openssl
- signapk
OTA原始包
可用于生成OTA的文件一版在目录out/target/product/somename/obj/PACKAGING/target_files_intermediates下。
OTA中system下文件的权限设置
ota_from_target_files中：
@classmethod
def GetMetadata(cls, input_zip):
The target_files contains a record of what the uid,
gid, and mode are supposed to be.
output = input_zip.read("META/filesystem_config.txt")
for line in output.split("\n"):
if not line: continue
columns = line.split()
name, uid, gid, mode = columns[:4]
selabel = None
capabilities = None
After the first 4 columns, there are a series of key=value
pairs. Extract out the fields we care about.
for element in columns[4:]:
key, value = element.split("=")
if key == "selabel":
selabel = value
if key == "capabilities":
capabilities = value
i = cls.ITEMS.get(name, None)
if i is not None:
i.uid = int(uid)
i.gid = int(gid)
i.mode = int(mode, 8)
i.selabel = selabel
i.capabilities = capabilities
if i.dir:
i.children.sort(key=lambda i: i.name)
set metadata for the files generated by this script.
i = cls.ITEMS.get("system/recovery-from-boot.p", None)
if i: i.uid, i.gid, i.mode, i.selabel, i.capabilities = 0, 0, 0644, None, None
i = cls.ITEMS.get("system/etc/install-recovery.sh", None)
if i: i.uid, i.gid, i.mode, i.selabel, i.capabilities = 0, 0, 0544, None, None
从上面的代码可以看到脚本读取的是META/filesystem_config.txt中的内容，这个文件是有源码编译的生成的。所以如果你增加了一些apk到image中，然后制作OTA，你需要自己赋予你的apk相应的权限,否则在生成OTA的时候就会出错（找不到 uid, gid, mode …），不要试图随意赋这些值。
filesystem_config.txt
这个文件是在build/core/Makefile中生成的：
$(hide) zipinfo -1 [email protected] | awk 'BEGIN { FS="SYSTEM/" } /^SYSTEM\// {print "system/" $$2}' | $(HOST_OUT_EXECUTABLES)/fs_config -C -S $(SELINUX_FC) > $(zip_root)/META/filesystem_config.txt
$(hide) zipinfo -1 [email protected] | awk 'BEGIN { FS="BOOT/RAMDISK/" } /^BOOT\/RAMDISK\// {print $$2}' | $(HOST_OUT_EXECUTABLES)/fs_config -C -S $(SELINUX_FC) > $(zip_root)/META/boot_filesystem_config.txt
$(hide) zipinfo -1 [email protected] | awk 'BEGIN { FS="RECOVERY/RAMDISK/" } /^RECOVERY\/RAMDISK\// {print $$2}' | $(HOST_OUT_EXECUTABLES)/fs_config -C -S $(SELINUX_FC) > $(zip_root)/META/recovery_filesystem_config.txt
$(hide) (cd $(zip_root) && zip -q ../$(notdir [email protected]) META/*filesystem_config.txt)
fs_config
这个工具是生成上一步中的filesystem_config.txt的核心，其源码在build/tools/fs_config
参数说明:
// This program takes a list of files and directories (indicated by a
// trailing slash) on the stdin, and prints to stdout each input
// filename along with its desired uid, gid, and mode (in octal).
// The leading slash should be stripped from the input.
//
// After the first 4 columns, optional key=value pairs are emitted
// for each file. Currently, the following keys are supported:
// * -S: selabel=[selinux_label]
// * -C: capabilities=[hex capabilities value]
//
// Example input:
//
// system/etc/dbus.conf
// data/app/
//
// Output:
//
// system/etc/dbus.conf 1002 1002 440
// data/app 1000 1000 771
//
// or if, for example, -S is used:
//
// system/etc/dbus.conf 1002 1002 440 selabel=u:object_r:system_file:s0
// data/app 1000 1000 771 selabel=u:object_r:apk_data_file:s0
//
// Note that the output will omit the trailing slash from
// directories.
