修改android系统默认字体大小

原文：http://blog.chinaunix.net/uid-29535415-id-4150770.html

android系统字体大小在“设置” 中“显示”中“字体大小”设置，一共提四种等级设置：小 、普通 、 大、 超大

四种等级选择相应配置代码位置

packages/apps/setttings/res/values/arrays.xml
<string-array name="entries_font_size">
<item msgid="6490061470416867723">Small</item>
<item msgid="3579015730662088893">Normal</item>
<item msgid="1678068858001018666">Large</item>
<item msgid="490158884605093126">Huge</item>
</string-array>

<string-array name="entryvalues_font_size" translatable="false">
<item>0.85</item>
<item>1.0</item>
<item>1.15</item>
<item>1.30</item>
</string-array>

以上配置是通过如下代码加载后供给终端用户选择
packages/app/settings/DisplaySettings.java

public void readFontSizePreference(ListPreference pref) {
try {
mCurConfig.updateFrom(ActivityManagerNative.getDefault().getConfiguration());
} catch (RemoteException e) {
Log.w(TAG, "Unable to retrieve font size");
}

// mark the appropriate item in the preferences list
int index = floatToIndex(mCurConfig.fontScale);
pref.setValueIndex(index);

// report the current size in the summary text
final Resources res = getResources();
String[] fontSizeNames = res.getStringArray(R.array.entries_font_size);
pref.setSummary(String.format(res.getString(R.string.summary_font_size),
fontSizeNames[index]));
}

在frameworks层会对系统的字体大小设置一个默认值，字体放缩比例为1，也就是对应显示设置中的“普通”字体

frameworks/base/core/java/android/content/res/Configuration.java

/**
* Set this object to the system defaults.
*/
public void setToDefaults() {
fontScale = 1; //此处赋值为默认字体的放缩比例
mcc = mnc = 0;
locale = null;
userSetLocale = false;
touchscreen = TOUCHSCREEN_UNDEFINED;
keyboard = KEYBOARD_UNDEFINED;
keyboardHidden = KEYBOARDHIDDEN_UNDEFINED;
hardKeyboardHidden = HARDKEYBOARDHIDDEN_UNDEFINED;
navigation = NAVIGATION_UNDEFINED;
navigationHidden = NAVIGATIONHIDDEN_UNDEFINED;
orientation = ORIENTATION_UNDEFINED;
screenLayout = SCREENLAYOUT_UNDEFINED;
uiMode = UI_MODE_TYPE_UNDEFINED;
screenWidthDp = compatScreenWidthDp = SCREEN_WIDTH_DP_UNDEFINED;
screenHeightDp = compatScreenHeightDp = SCREEN_HEIGHT_DP_UNDEFINED;
smallestScreenWidthDp = compatSmallestScreenWidthDp = SMALLEST_SCREEN_WIDTH_DP_UNDEFINED;
densityDpi = DENSITY_DPI_UNDEFINED;
seq = 0;
}