系统版本：Android 4.2.2_r1
本文主要是在Android中添加思源字体的过程记录。思源字体是Google和Adobe在2014.07.18发布的中文字体。
1.获取思源字体(Google:Noto Sans CJK; Adobe:Source Han Sans)。
2.解压后如下几个才是思源字体。
- NotoSansHans-Regular.otf 常规
- NotoSansHans-Black.otf 黑体
- NotoSansHans-DemiLight.otf
- NotoSansHans-Medium.otf
- NotoSansHans-Thin.otf
- NotoSansHans-Bold.otf 加粗
- NotoSansHans-Light.otf
注：这里说下otf，意为opentype和ttf(truetype)是兼容的。
3.安装体验
由于Android中只使用到常规和加粗体，这里也只以这两个做实验(同时也有容量的考虑)，在高PPI（分辨率）的屏幕上或许只是感觉到字形变了，在低分辨率的屏幕上变的更加清晰了，前后对比：
之前：
之后：
(上传到这里就不清晰了，真是怪,点击链接看原图更为清晰)
1) 将NotoSansHans-Regular.otf NotoSansHans-Bold.otf放到/system/fonts/目录下。
2) 将如下fallback_fonts.xml放到/vendor/etc/下。
<?xml version="1.0" encoding="utf-8"?>
<!--
Vendor-provided fallback fonts
This file can be edited to add references to fonts that are not installed or referenced in the
default system. The file should then be placed in /vendor/etc/fallback_fonts.xml. Note
that in your makefile, this directory should be referenced as $(TARGET_COPY_OUT_VENDOR)/etc/:
PRODUCT_COPY_FILES += \
frameworks/base/data/fonts/vendor_fonts.xml:$(TARGET_COPY_OUT_VENDOR)/etc/fallback_fonts.xml
For example, vendors might want to build configurations for locales that are
better served by fonts which either handle glyphs not supported in the default fonts or which
handle these glyphs differently than the default fallback fonts.
Each entry in this list is a "family", which consists of a list of "files"
(the filenames for that family). The files objects are
provided in the order of the styles supported for that family: regular, bold, italic, and
bold-italic. Only providing one font means that all styles will be rendered with that font.
Providing two means that these two fonts will render regular and bold fonts (italics will
be mapped to these two fonts).
There is also an optional "order" attribute on the Family tag. This specifies the index at
which that family of fonts should be inserted in the fallback font list, where the
default fallback fonts on the system (in /system/etc/fallback_fonts.xml) start at index 0.
If no ‘order‘ attribute is supplied, that family will be inserted either at the end of the
current fallback list (if no order was supplied for any previous family in this file) or
after the previous family (if there was an order specified previously). Typically, vendors
may want to supply an order for the first family that puts this set of fonts at the appropriate
place in the overall fallback fonts. The order of this list determines which fallback font
will be used to support any glyphs that are not handled by the default system fonts.
Han languages (Chinese, Japanese, and Korean) share a common range of unicode characters;
their ordering in the fallback or vendor files gives priority to the first in the list.
Language-specific ordering can be configured by adding a BCP 47-style "lang" attribute to
a "file" element; fonts matching the language of text being drawn will be prioritised over
all others.
The sample configuration below is an example of how one might provide two families of fonts
that get inserted at the first and second (0 and 1) position in the overall fallback fonts.
See /system/etc/system_fonts.xml and /system/etc/fallback_fonts.xml for more information
and to understand the order in which the default system fonts are loaded and structured for
lookup.
-->
<!-- Sample fallback font additions to the default fallback list. These fonts will be added
to the top two positions of the fallback list, since the first has an order of 0. -->
<familyset>
<family order="0">
<fileset>
<file>NotoSansHans-Regular.otf</file>
<file>NotoSansHans-Bold.otf</file>
</fileset>
</family>
<!-- Italic 等等会造成启动不了的问题，所以只添加前两个足矣。
<family>
<fileset>
<file>NotoSansHans-Regular.otf</file>
<file>NotoSansHans-Italic.otf</file>
<file>NotoSansHans-Bolditalic.otf</file>
<file>NotoSansHans-Black.otf</file>
<file>NotoSansHans-DemiLight.otf</file>
<file>NotoSansHans-Light.otf</file>
<file>NotoSansHans-Medium.otf</file>
<file>NotoSansHans-Thin.otf</file>
</fileset>
</family>
-->
</familyset>
同时也有做好的字库加xml在这里下载，还原的时将这三个文件删除即可。
4.以源码方式添加
如果需要在制作rom时就可以自动添加默认中文字体，思路和上边的类似，以下是git log信息。
commit xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Author: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Date: Mon Aug 18 15:44:24 2014 +0800
Add Noto Sans CJK fonts for Chinese
diff --git a/device/rockchip/rk30sdk/device.mk b/device/rockchip/rk30sdk/device.mk
index 8befd40..b4e2822 100755
--- a/device/rockchip/rk30sdk/device.mk
+++ b/device/rockchip/rk30sdk/device.mk
@@ -119,6 +119,10 @@ PRODUCT_COPY_FILES += \
+#fonts
+PRODUCT_COPY_FILES += \
+ frameworks/base/data/fonts/vendor_fonts.xml:$(TARGET_COPY_OUT_VENDOR)/etc/fallback_fonts.xml
diff --git a/frameworks/base/data/fonts/Android.mk b/frameworks/base/data/fonts/Android.mk
index e02e95a..0b4bc6c 100755
--- a/frameworks/base/data/fonts/Android.mk
+++ b/frameworks/base/data/fonts/Android.mk
@@ -157,6 +157,8 @@ font_src_files += \
DroidSansHebrew-Regular.ttf \
DroidSansHebrew-Bold.ttf \
DroidSansThai.ttf \
+ NotoSansHans-Regular.otf \
+ NotoSansHans-Bold.otf \
DroidSansArmenian.ttf \
DroidSansGeorgian.ttf \
AndroidEmoji.ttf
diff --git a/frameworks/base/data/fonts/NotoSansHans-Bold.otf b/frameworks/base/data/fonts/NotoSansHans-Bold.otf
new file mode 100644
index 0000000..006372e
Binary files /dev/null and b/frameworks/base/data/fonts/NotoSansHans-Bold.otf differ
diff --git a/frameworks/base/data/fonts/NotoSansHans-Regular.otf b/frameworks/base/data/fonts/NotoSansHans-Regular.otf
new file mode 100644
index 0000000..923f89c
Binary files /dev/null and b/frameworks/base/data/fonts/NotoSansHans-Regular.otf differ
diff --git a/frameworks/base/data/fonts/fonts.mk b/frameworks/base/data/fonts/fonts.mk
index 875795a..490c6e6 100755
--- a/frameworks/base/data/fonts/fonts.mk
+++ b/frameworks/base/data/fonts/fonts.mk
@@ -38,6 +38,8 @@ PRODUCT_PACKAGES := \
DroidSansHebrew-Regular.ttf \
DroidSansHebrew-Bold.ttf \
DroidSansThai.ttf \
+ NotoSansHans-Regular.otf \
+ NotoSansHans-Bold.otf \
DroidSerif-Regular.ttf \
DroidSerif-Bold.ttf \
DroidSerif-Italic.ttf \
diff --git a/frameworks/base/data/fonts/vendor_fonts.xml b/frameworks/base/data/fonts/vendor_fonts.xml
index 8690ee1..fba0c88 100755
--- a/frameworks/base/data/fonts/vendor_fonts.xml
+++ b/frameworks/base/data/fonts/vendor_fonts.xml
@@ -45,17 +45,26 @@
<!-- Sample fallback font additions to the default fallback list. These fonts will be added
to the top two positions of the fallback list, since the first has an order of 0. -->
-<!--
<familyset>
<family order="0">
<fileset>
- <file>MyFont.ttf</file>
+ <file>NotoSansHans-Regular.otf</file>
+ <file>NotoSansHans-Bold.otf</file>
</fileset>
</family>
+
+<!-- Italic 等等会造成启动不了的问题，所以只添加前两个足矣。
<family>
<fileset>
- <file>MyOtherFont.ttf</file>
+ <file>NotoSansHans-Regular.otf</file>
+ <file>NotoSansHans-Italic.otf</file>
+ <file>NotoSansHans-Bolditalic.otf</file>
+ <file>NotoSansHans-Black.otf</file>
+ <file>NotoSansHans-DemiLight.otf</file>
+ <file>NotoSansHans-Light.otf</file>
+ <file>NotoSansHans-Medium.otf</file>
+ <file>NotoSansHans-Thin.otf</file>
</fileset>
</family>
+-->
</familyset>
---->
需要强调一点，关于字体拷贝，经过测试发现需要同时修改Android.mk和fonts.mk才可以完成拷贝。Google是以Apache License, version 2.0协议发布的，所以大可不必担心会有律师函的问题，在高版本的Android中这套字体已经是内置到Android中了。DroidSansFallback.ttf并不是完全指中文字体，由于之前并没有开发出专心的中文字体，目前处理方法是把所以暂时不规范的字体都放入了DroidSansFallback.ttf中，Fallback是备胎的意思，所有的胎都爆了才会使用这个。
参考：《关于Android的字体》。低版本的Android参考《Android 如何增加新的字库》 <完>