需求：替换系统字体
分析：
过程：frameworks/base/data/fonts/fonts.xml
external/roboto-fonts/
noto-fonts/other/
关于字体上层主要在
frameworks/base/graphics/java/android/graphics/Typeface.java
static {
final ArrayMap systemFontMap =new ArrayMap<>();
final ArrayMap systemFallbackMap =new ArrayMap<>();
buildSystemFallback("/system/etc/fonts.xml","/system/fonts/", systemFontMap,
systemFallbackMap);
sSystemFontMap = Collections.unmodifiableMap(systemFontMap);
sSystemFallbackMap = Collections.unmodifiableMap(systemFallbackMap);
setDefault(sSystemFontMap.get(DEFAULT_FAMILY));
// Set up defaults and typefaces exposed in public API
DEFAULT =create((String)null,0);
DEFAULT_BOLD =create((String)null, Typeface.BOLD);
SANS_SERIF =create("sans-serif",0);
SERIF =create("serif",0);
MONOSPACE =create("monospace",0);
sDefaults =new Typeface[] {
DEFAULT,
DEFAULT_BOLD,
create((String)null, Typeface.ITALIC),
create((String)null, Typeface.BOLD_ITALIC),
};
}
static代码块 是系统typeface的初始化
DEFAULT 、DEFAULT_BOLD 、SANS_SERIF、SERIF、MONOSPACE
因为DEFAULT_FAMILY ="sans-serif" 所以DEFAULT = SANS_SERIF DEFAULT_BOLD = SANS_SERIF + BOLD
所以先介绍下三种familyName的含义
sans-serif：区别于“serif”，没有"笔锋"，笔画粗细也基本差不多
serif：带“笔锋”，而且根据横竖斜的宽度也不一样
monospace：打印用字体，属于“sans-serif”，每个字母等间距
其次介绍下"font-weight"，
weight指的是粗细”
那么默认的weight是多少？
===>>>Typeface.java
create(null,0);
nativeCreateFromTypeface(ni, style)
===>>>Typeface.cpp
frameworks/base/core/jni/android/graphics/Typeface.cpp
Typeface* face = Typeface::createRelative(family, (SkTypeface::Style)style);
===>>>Typeface.cpp
frameworks/base/libs/hwui/hwui/Typeface.cpp
Typeface* Typeface::createRelative(Typeface* src, SkTypeface::Style style) {
Typeface* resolvedFace = Typeface::resolveDefault(src);
Typeface* hwTypeface = new Typeface();
hwTypeface->fFontCollection = collection;
hwTypeface->fSkiaStyle = SkTypeface::kNormal;
hwTypeface->fBaseWeight = SkFontStyle::kNormal_Weight;
hwTypeface->fStyle = minikin::FontStyle(4 /* weight */, false /* italic */);
Typeface::setDefault(hwTypeface);
===>>>SkFontStyle.h
external/skia/include/core/SkFontStyle.h
enum Weight {
kInvisible_Weight = 0,
kThin_Weight = 100,
kExtraLight_Weight = 200,
kLight_Weight = 300,
kNormal_Weight = 400,
kMedium_Weight = 500,
kSemiBold_Weight = 600,
kBold_Weight = 700,
kExtraBold_Weight = 800,
kBlack_Weight = 900,
kExtraBlack_Weight = 1000,
};
所以默认的weight是400
再根据frameworks/base/data/fonts/fonts.mk 找到Roboto-Regular.ttf 才是默认的自体文件
<family name="sans-serif">
<font weight="100" style="normal">Roboto-Thin.ttf</font>
<font weight="100" style="italic">Roboto-ThinItalic.ttf</font>
<font weight="300" style="normal">Roboto-Light.ttf</font>
<font weight="300" style="italic">Roboto-LightItalic.ttf</font>
<font weight="400" style="normal">Roboto-Regular.ttf</font>
<font weight="400" style="italic">Roboto-Italic.ttf</font>
<font weight="500" style="normal">Roboto-Medium.ttf</font>
<font weight="500" style="italic">Roboto-MediumItalic.ttf</font>
<font weight="900" style="normal">Roboto-Black.ttf</font>
<font weight="900" style="italic">Roboto-BlackItalic.ttf</font>
<font weight="700" style="normal">Roboto-Bold.ttf</font>
<font weight="700" style="italic">Roboto-BoldItalic.ttf</font>
</family>
其中要注意ttc文件
```
1234
```
<family lang="zh-Hans">
<font weight="400" style="normal" index="2">NotoSansCJK-Regular.ttc</font>
</family>
<!-- TODO: Add Bopo -->
<family lang="zh-Hant">
<font weight="400" style="normal" index="3">NotoSansCJK-Regular.ttc</font>
</family>
<family lang="ja">
<font weight="400" style="normal" index="0">NotoSansCJK-Regular.ttc</font>
</family>
<family lang="ko">
<font weight="400" style="normal" index="1">NotoSansCJK-Regular.ttc</font>
</family>
```
