查询/设置Settings的值

     按计划每周更新一篇技术博文，第四篇：《查询/设置Settings的值 》

    通常很多定制系统或者与系统相关的应用都需要查询/设置 Settings（设置）里边的值，比如系统亮度，休眠时间，锁屏之类的系统设置等，主要通过 SettingsProvider来查询/设置，前提是要知道所要修改的值的数据类型与字符串代表的name。

    对应的name值与数据类型在./ics/frameworks/base/core/java/android/provider/Settings.java文件中,例举两个例子如下：

1.查询休眠时间：

/**
* 获取系统休眠时间
* @return 秒数(从不待机 返回0)
*/
public static String getTimeOut(ContentResolver resolver){
int timeOut = 0;
try {
timeOut = android.provider.Settings.System.getInt(resolver, Settings.System.SCREEN_BRIGHTNESS);
timeOut /= 1000;
} catch (SettingNotFoundException e) {
e.printStackTrace();
}
String timeOutStr = timeOut + "";
return timeOutStr;
}

2.更改系统亮度：

/**
* 保存亮度设置状态
* 改变setting值
* @param resolver
* @param brightness : 0~1
*/
public static void saveBrightness(ContentResolver resolver, float brightness) {
Uri uri = android.provider.Settings.System
.getUriFor(Settings.System.SCREEN_BRIGHTNESS);
android.provider.Settings.System.putInt(resolver, Settings.System.SCREEN_BRIGHTNESS,
(int)(brightness*255));
resolver.notifyChange(uri, null);
}

需要权限：

<uses-permission android:name="android.permission.WRITE_SETTINGS" />

PS：

a.查询Settings中各个属性所对应的值（Android APIs）：http://developer.android.com/reference/android/provider/Settings.System.html

b.ContentResolver Context提供getContentResolver()方法可以获取ContentResolver对象，便可以操作文中前边所提的 SettingsProvider所暴露的数据。

c.Android系统提供大量的SettingsProvider，Settings除外，常用的还有管理联系人（ContactsContract）、短信（Telephony）、多媒体数据（MediaStore）等，对应的URI可到这里查看：http://developer.android.com/reference/android/provider/package-summary.html，源码路径：./ics/frameworks/base/core/java/android/provider/

d.Settings默认初始值的位置（修改之前最好弄明白先，修改后再测试一下）： frameworks/base/packages/SettingsProvider/res/values/defaults.xml

=========================================================================

Android中的android.provider.Settings.System系统属性设定

Content Provider中的Setting.System表格内存储了很多系统属性的值，以键值对的形式存在！

可以对如下的变量进行设置

Constants
String	ACCELEROMETER_ROTATION	Control whether the accelerometer will be used to change screen orientation.
String	ADB_ENABLED	This constant is deprecated. Use ADB_ENABLED instead
String	AIRPLANE_MODE_ON	Whether Airplane Mode is on.
String	AIRPLANE_MODE_RADIOS	A comma separated list of radios that need to be disabled when airplane mode is on.
String	ALARM_ALERT	Persistent store for the system-wide default alarm alert.
String	ALWAYS_FINISH_ACTIVITIES	If 1, the activity manager will aggressively finish activities and processes as soon as they are no longer needed.
String	ANDROID_ID	This constant is deprecated. Use ANDROID_ID instead
String	APPEND_FOR_LAST_AUDIBLE	Appended to various volume related settings to record the previous values before they the settings were affected by a silent/vibrate ringer mode change.
String	AUTO_TIME	Value to specify if the user prefers the date, time and time zone to be automatically fetched from the network (NITZ).
String	AUTO_TIME_ZONE	Value to specify if the user prefers the time zone to be automatically fetched from the network (NITZ).
String	BLUETOOTH_DISCOVERABILITY	Determines whether remote devices may discover and/or connect to this device.
String	BLUETOOTH_DISCOVERABILITY_TIMEOUT	Bluetooth discoverability timeout.
String	BLUETOOTH_ON	This constant is deprecated. Use BLUETOOTH_ON instead
String	DATA_ROAMING	This constant is deprecated. Use DATA_ROAMING instead
String	DATE_FORMAT	Date format string mm/dd/yyyy dd/mm/yyyy yyyy/mm/dd
String	DEBUG_APP	Name of an application package to be debugged.
String	DEVICE_PROVISIONED	This constant is deprecated. Use DEVICE_PROVISIONEDinstead
String	DIM_SCREEN	Whether or not to dim the screen.
String	DTMF_TONE_WHEN_DIALING	Whether the audible DTMF tones are played by the dialer when dialing.
String	END_BUTTON_BEHAVIOR	What happens when the user presses the end call button if they're not on a call.
String	FONT_SCALE	Scaling factor for fonts, float.
String	HAPTIC_FEEDBACK_ENABLED	Whether the haptic feedback (long presses, ...) are enabled.
String	HTTP_PROXY	This constant is deprecated. Use HTTP_PROXY instead
String	INSTALL_NON_MARKET_APPS	This constant is deprecated. UseINSTALL_NON_MARKET_APPS instead
String	LOCATION_PROVIDERS_ALLOWED	This constant is deprecated. UseLOCATION_PROVIDERS_ALLOWED instead
String	LOCK_PATTERN_ENABLED	This constant is deprecated. Use LOCK_PATTERN_ENABLEDinstead
String	LOCK_PATTERN_TACTILE_FEEDBACK_ENABLED	This constant is deprecated. UseLOCK_PATTERN_TACTILE_FEEDBACK_ENABLED instead
String	LOCK_PATTERN_VISIBLE	This constant is deprecated. Use LOCK_PATTERN_VISIBLEinstead
String	LOGGING_ID	This constant is deprecated. Use LOGGING_ID instead
String	MODE_RINGER	Ringer mode.
String	MODE_RINGER_STREAMS_AFFECTED	Determines which streams are affected by ringer mode changes.
String	MUTE_STREAMS_AFFECTED	Determines which streams are affected by mute.
String	NETWORK_PREFERENCE	This constant is deprecated. Use NETWORK_PREFERENCEinstead
String	NEXT_ALARM_FORMATTED	A formatted string of the next alarm that is set, or the empty string if there is no alarm set.
String	NOTIFICATION_SOUND	Persistent store for the system-wide default notification sound.
String	PARENTAL_CONTROL_ENABLED	This constant is deprecated. UsePARENTAL_CONTROL_ENABLED instead
String	PARENTAL_CONTROL_LAST_UPDATE	This constant is deprecated. UsePARENTAL_CONTROL_LAST_UPDATE instead
String	PARENTAL_CONTROL_REDIRECT_URL	This constant is deprecated. UsePARENTAL_CONTROL_REDIRECT_URL instead
String	RADIO_BLUETOOTH	Constant for use in AIRPLANE_MODE_RADIOS to specify Bluetooth radio.
String	RADIO_CELL	Constant for use in AIRPLANE_MODE_RADIOS to specify Cellular radio.
String	RADIO_NFC	Constant for use in AIRPLANE_MODE_RADIOS to specify NFC radio.
String	RADIO_WIFI	Constant for use in AIRPLANE_MODE_RADIOS to specify Wi-Fi radio.
String	RINGTONE	Persistent store for the system-wide default ringtone URI.
String	SCREEN_BRIGHTNESS	The screen backlight brightness between 0 and 255.
String	SCREEN_BRIGHTNESS_MODE	Control whether to enable automatic brightness mode.
int	SCREEN_BRIGHTNESS_MODE_AUTOMATIC	SCREEN_BRIGHTNESS_MODE value for automatic mode.
int	SCREEN_BRIGHTNESS_MODE_MANUAL	SCREEN_BRIGHTNESS_MODE value for manual mode.
String	SCREEN_OFF_TIMEOUT	The timeout before the screen turns off.
String	SETTINGS_CLASSNAME	This constant is deprecated. Use SETTINGS_CLASSNAMEinstead
String	SETUP_WIZARD_HAS_RUN	Whether the setup wizard has been run before (on first boot), or if it still needs to be run.
String	SHOW_GTALK_SERVICE_STATUS
String	SHOW_PROCESSES	Control whether the process CPU usage meter should be shown.
String	SHOW_WEB_SUGGESTIONS	This constant is deprecated. Each application that shows web suggestions should have its own setting for this.
String	SOUND_EFFECTS_ENABLED	Whether the sounds effects (key clicks, lid open ...) are enabled.
String	STAY_ON_WHILE_PLUGGED_IN	Whether we keep the device on while the device is plugged in.
String	SYS_PROP_SETTING_VERSION
String	TEXT_AUTO_CAPS	Setting to enable Auto Caps in text editors.
String	TEXT_AUTO_PUNCTUATE	Setting to enable Auto Punctuate in text editors.
String	TEXT_AUTO_REPLACE	Setting to enable Auto Replace (AutoText) in text editors.
String	TEXT_SHOW_PASSWORD	Setting to showing password characters in text editors.
String	TIME_12_24	Display times as 12 or 24 hours 12 24
String	TRANSITION_ANIMATION_SCALE	Scaling factor for activity transition animations.
String	USB_MASS_STORAGE_ENABLED	This constant is deprecated. UseUSB_MASS_STORAGE_ENABLED instead
String	USER_ROTATION	Default screen rotation when no other policy applies.
String	USE_GOOGLE_MAIL	This constant is deprecated. Use USE_GOOGLE_MAILinstead
String	VIBRATE_ON	Whether vibrate is on for different events.
String	VOLUME_ALARM	Alarm volume.
String	VOLUME_BLUETOOTH_SCO	Bluetooth Headset volume.
String	VOLUME_MUSIC	Music/media/gaming volume.
String	VOLUME_NOTIFICATION	Notification volume.
String	VOLUME_RING	Ringer volume.
String	VOLUME_SYSTEM	System/notifications volume.
String	VOLUME_VOICE	Voice call volume.
String	WAIT_FOR_DEBUGGER	If 1, when launching DEBUG_APP it will wait for the debugger before starting user code.
String	WALLPAPER_ACTIVITY	Name of activity to use for wallpaper on the home screen.
String	WIFI_MAX_DHCP_RETRY_COUNT	This constant is deprecated. UseWIFI_MAX_DHCP_RETRY_COUNT instead
String	WIFI_MOBILE_DATA_TRANSITION_WAKELOCK_TIMEOUT_MS	This constant is deprecated. UseWIFI_MOBILE_DATA_TRANSITION_WAKELOCK_TIMEOUT_MSinstead
String	WIFI_NETWORKS_AVAILABLE_NOTIFICATION_ON	This constant is deprecated. UseWIFI_NETWORKS_AVAILABLE_NOTIFICATION_ON instead
String	WIFI_NETWORKS_AVAILABLE_REPEAT_DELAY	This constant is deprecated. UseWIFI_NETWORKS_AVAILABLE_REPEAT_DELAY instead
String	WIFI_NUM_OPEN_NETWORKS_KEPT	This constant is deprecated. UseWIFI_NUM_OPEN_NETWORKS_KEPT instead
String	WIFI_ON	This constant is deprecated. Use WIFI_ON instead
String	WIFI_SLEEP_POLICY	The policy for deciding when Wi-Fi should go to sleep (which will in turn switch to using the mobile data as an Internet connection).
int	WIFI_SLEEP_POLICY_DEFAULT	Value for WIFI_SLEEP_POLICY to use the default Wi-Fi sleep policy, which is to sleep shortly after the turning off according to the STAY_ON_WHILE_PLUGGED_IN setting.
int	WIFI_SLEEP_POLICY_NEVER	Value for WIFI_SLEEP_POLICY to never go to sleep.
int	WIFI_SLEEP_POLICY_NEVER_WHILE_PLUGGED	Value for WIFI_SLEEP_POLICY to use the default policy when the device is on battery, and never go to sleep when the device is plugged in.
String	WIFI_STATIC_DNS1	If using static IP, the primary DNS's IP address.
String	WIFI_STATIC_DNS2	If using static IP, the secondary DNS's IP address.
String	WIFI_STATIC_GATEWAY	If using static IP, the gateway's IP address.
String	WIFI_STATIC_IP	The static IP address.
String	WIFI_STATIC_NETMASK	If using static IP, the net mask.
String	WIFI_USE_STATIC_IP	Whether to use static IP and other static network attributes.
String	WIFI_WATCHDOG_ACCEPTABLE_PACKET_LOSS_PERCENTAGE	This constant is deprecated. UseWIFI_WATCHDOG_ACCEPTABLE_PACKET_LOSS_PERCENTAGEinstead
String	WIFI_WATCHDOG_AP_COUNT	This constant is deprecated. UseWIFI_WATCHDOG_AP_COUNT instead
String	WIFI_WATCHDOG_BACKGROUND_CHECK_DELAY_MS	This constant is deprecated. UseWIFI_WATCHDOG_BACKGROUND_CHECK_DELAY_MS instead
String	WIFI_WATCHDOG_BACKGROUND_CHECK_ENABLED	This constant is deprecated. UseWIFI_WATCHDOG_BACKGROUND_CHECK_ENABLED instead
String	WIFI_WATCHDOG_BACKGROUND_CHECK_TIMEOUT_MS	This constant is deprecated. UseWIFI_WATCHDOG_BACKGROUND_CHECK_TIMEOUT_MSinstead
String	WIFI_WATCHDOG_INITIAL_IGNORED_PING_COUNT	This constant is deprecated. UseWIFI_WATCHDOG_INITIAL_IGNORED_PING_COUNT instead
String	WIFI_WATCHDOG_MAX_AP_CHECKS	This constant is deprecated. UseWIFI_WATCHDOG_MAX_AP_CHECKS instead
String	WIFI_WATCHDOG_ON	This constant is deprecated. Use WIFI_WATCHDOG_ONinstead
String	WIFI_WATCHDOG_PING_COUNT	This constant is deprecated. UseWIFI_WATCHDOG_PING_COUNT instead
String	WIFI_WATCHDOG_PING_DELAY_MS	This constant is deprecated. UseWIFI_WATCHDOG_PING_DELAY_MS instead
String	WIFI_WATCHDOG_PING_TIMEOUT_MS	This constant is deprecated. UseWIFI_WATCHDOG_PING_TIMEOUT_MS instead
String	WINDOW_ANIMATION_SCALE	Scaling factor for normal window animations.

通过如下的函数可以对其进行读写：

static void	getConfiguration( ContentResolver cr,  Configuration outConfig) Convenience function to read all of the current configuration-related settings into a Configuration object.
static float	getFloat( ContentResolver cr,  String name, float def) Convenience function for retrieving a single system settings value as a floating point number.
static float	getFloat( ContentResolver cr,  String name) Convenience function for retrieving a single system settings value as a float.
static int	getInt( ContentResolver cr,  String name) Convenience function for retrieving a single system settings value as an integer.
static int	getInt( ContentResolver cr,  String name, int def) Convenience function for retrieving a single system settings value as an integer.
static long	getLong( ContentResolver cr,  String name, long def) Convenience function for retrieving a single system settings value as a  long.
static long	getLong( ContentResolver cr,  String name) Convenience function for retrieving a single system settings value as a  long.
static boolean	getShowGTalkServiceStatus( ContentResolver cr)
synchronized static  String	getString( ContentResolver resolver,  String name) Look up a name in the database.
static  Uri	getUriFor( String name) Construct the content URI for a particular name/value pair, useful for monitoring changes with a ContentObserver.
static boolean	putConfiguration( ContentResolver cr,  Configuration config) Convenience function to write a batch of configuration-related settings from a Configuration object.
static boolean	putFloat( ContentResolver cr,  String name, float value) Convenience function for updating a single settings value as a floating point number.
static boolean	putInt( ContentResolver cr,  String name, int value) Convenience function for updating a single settings value as an integer.
static boolean	putLong( ContentResolver cr,  String name, long value) Convenience function for updating a single settings value as a long integer.
static boolean	putString( ContentResolver resolver,  String name,  String value) Store a name/value pair into the database.
static void	setShowGTalkServiceStatus( ContentResolver cr, boolean flag)

注意，应用程序中应加入： <uses-permission android:name="android.permission.WRITE_SETTINGS" />