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SystemProperties跟Settings.System
1 使用 SystemProperties.get
如果属性名称以“ro.”开头，那么这个属性被视为只读属性。一旦设置，属性值不能改变。
如果属性名称以“persist.”开头，当设置这个属性时，其值也将写入/data/property。
JAVA代码如下：
import android.os.SystemProperties; //设定 SystemProperties.set("persist.sys.language", "默认值"); //读取 String lang= SystemProperties.get("persist.sys.language");//string int lang = SystemProperties.getInt("persist.sys.language",10); boolean fastfoodenable = SystemProperties.getBoolean("persist.sys.fastfoodenable", false);//boolean
创建与修改android属性用
Systemproperties.set(name, value)；
获取android属性用
Systemproperties.get(name)；
需要注意的是android属性的名称是有一定的格式要求的，
前缀必须用system\core\init\property_service.c中定义的前缀
property_service.c的内容如下
property_perms[] = { { "net.rmnet0.", AID_RADIO, 0 }, { "net.gprs.", AID_RADIO, 0 }, { "net.ppp", AID_RADIO, 0 }, { "net.qmi", AID_RADIO, 0 }, { "net.lte", AID_RADIO, 0 }, { "net.cdma", AID_RADIO, 0 }, { "ril.", AID_RADIO, 0 }, { "persist.ril.", AID_RADIO, 0 }, { "persist.ril.cfu.querytype", AID_APP, 0 }, { "mux.", AID_RADIO, 0 }, { "mux.", AID_SYSTEM, 0 }, { "mtk_telephony_mode_slot1", AID_SYSTEM, 0 }, { "mtk_telephony_mode_slot2", AID_SYSTEM, 0 }, { "gsm.", AID_RADIO, 0 }, { "persist.radio", AID_RADIO, 0 }, { "net.dns", AID_RADIO, 0 }, { "sys.usb.config", AID_RADIO, AID_SYSTEM }, { "net.", AID_SYSTEM, 0 }, { "net.", AID_DHCP, 0 }, { "dev.", AID_SYSTEM, 0 }, { "runtime.", AID_SYSTEM, 0 }, { "hw.", AID_SYSTEM, 0 }, { "sys.", AID_SYSTEM, 0 }, { "sys.powerctl", AID_SHELL, 0 }, { "service.", AID_SYSTEM, 0 }, { "wlan.", AID_SYSTEM, 0 }, { "bluetooth.", AID_BLUETOOTH, 0 }, { "dhcp.", AID_SYSTEM, 0 }, { "bwc.mm.", AID_SYSTEM, 0 }, { "dhcp.", AID_DHCP, 0 }, { "debug.", AID_SYSTEM, 0 }, { "debug.", AID_SHELL, 0 }, { "log.", AID_SHELL, 0 }, { "service.adb.root", AID_SHELL, 0 }, { "service.adb.tcp.port", AID_SHELL, 0 }, { "persist.sys.", AID_SYSTEM, 0 }, { "persist.service.", AID_SYSTEM, 0 }, { "persist.security.", AID_SYSTEM, 0 }, { "persist.service.bdroid.", AID_BLUETOOTH, 0 }, { "selinux." , AID_SYSTEM, 0 }, { "gps.", AID_GPS, AID_SYSTEM }, { "persist.af.", AID_MEDIA, 0 },
进行系统属性设置的程序也必须有 system或root权限
如果我们要添加一个property：例如：zhang
路径：
system/core/rootdir/init.rc
它的内容如下
on post-fs-data # We chown/chmod /data again so because mount is run as root + defaults chown system system /data chmod 0771 /data # We restorecon /data in case the userdata partition has been reset. restorecon /data # Avoid predictable entropy pool. Carry over entropy from previous boot. copy /data/system/entropy.dat /dev/urandom # Create dump dir and collect dumps. # Do this before we mount cache so eventually we can use cache for # storing dumps on platforms which do not have a dedicated dump partition. mkdir /data/dontpanic 0750 root log # Collect apanic data, free resources and re-arm trigger copy /proc/apanic_console /data/dontpanic/apanic_console chown root log /data/dontpanic/apanic_console chmod 0640 /data/dontpanic/apanic_console copy /proc/apanic_threads /data/dontpanic/apanic_threads chown root log /data/dontpanic/apanic_threads chmod 0640 /data/dontpanic/apanic_threads write /proc/apanic_console 1 # If there is no fs-post-data action in the init.<device>.rc file, you # must uncomment this line, otherwise encrypted filesystems # won‘t work. # Set indication (checked by vold) that we have finished this action #setprop vold.post_fs_data_done 1
在on post-fs-data 目录下
setprop persist.sys.zhang 1//persist.sys 前缀名； 1为初始值
PS:不同前缀名权限不同，这里就不一一说明；还有为什么要加载on post-fs-data目录下，这和int.rc的语法有关
2 使用 Settings.System.putInt
这种方式会保存变量到Settings 数据库中，飞行模式等的开关就是用这种方式实现的。
首先需要定义一个系统属性值
路径
frameworks/base/core/java/android/provider/Settings.java
添加一个属性标签
public static final String QS_DYNAMIC_WIFI = "qs_dyanmic_wifi"; /** * Quick Settings Quick Pulldown * * @hide */ public static final String QS_QUICK_PULLDOWN = "qs_quick_pulldown"; /** * Quick Settings Collapse Pane * * @hide */ public static final String QS_COLLAPSE_PANEL = "qs_collapse_panel"; /** * Quick Settings Quick access ribbon * * @hide */ public static final String QS_QUICK_ACCESS = "qs_quick_access"; //别忘了在这里面提添加 public static final String[] SETTINGS_TO_BACKUP = { QS_QUICK_PULLDOWN STAY_ON_WHILE_PLUGGED_IN, // moved to global WIFI_USE_STATIC_IP, WIFI_STATIC_IP, WIFI_STATIC_GATEWAY, WIFI_STATIC_NETMASK, WIFI_STATIC_DNS1, WIFI_STATIC_DNS2, BLUETOOTH_DISCOVERABILITY, BLUETOOTH_DISCOVERABILITY_TIMEOUT, DIM_SCREEN, SCREEN_OFF_TIMEOUT, SCREEN_BRIGHTNESS, SCREEN_BRIGHTNESS_MODE, SCREEN_AUTO_BRIGHTNESS_ADJ, VIBRATE_INPUT_DEVICES, MODE_RINGER_STREAMS_AFFECTED, VOLUME_VOICE, VOLUME_SYSTEM, VOLUME_RING, VOLUME_MUSIC, VOLUME_ALARM, }
1）获取方法如下：
Settings.System.getInt(getContentResolver(), Settings.System.QS_QUICK_PULLDOWN,0)；
第三个参数是默认值
2）设置
Settings.System.putInt(getContentResolver(),Settings.System.QS_QUICK_PULLDOWN, 1);
代码中使用的时候，需要导入包
需要import android.provider.Settings;
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原文地址：http://www.cnblogs.com/zhangshuli-1989/p/zhangshuli_setting_150414132.html
