android开发笔记之设置(settings)DB数据库

    在设置(settings)应用中，我们可以把一些值(int,boolean,string)保存在db数据库。这个值，我们可以在不同的app应用中使用。我们可以非常方便的在此上添加一些简单的代码，实现一个新的变量在db数据库中，方便不同的app来共同使用。

1.关键类和文件

frameworks\base\packages\settingsprovider\src\com\android\providers\settings\databaseHelper.java-------给变量赋值，我们可以把变量的初始值写到下面的defaults.xml文件中，使用后面的修改和统一管理。

frameworks\base\packages\settingsprovider\res\values\defaults.xml----------放置变量的初始值
有四种类型(bool, integer, string, fraction)四种类型
true
9
gps
100%

frameworks\base\core\java\android\provider\settings.java----------定义变量

2.我们以SET_INSTALL_LOCATION为例，让我们知道这个变量是如何定义使用的：

(1) frameworks\base\core\java\android\provider\settings.java---定义变量：

/**
* Let user pick default install location.
*
* @hide
*/
public static final String SET_INSTALL_LOCATION = "set_install_location";


MOVED_TO_GLOBAL.add(Settings.Global.SET_INSTALL_LOCATION);

(2) frameworks\base\packages\settingsprovider\src\com\android\providers\settings\ databaseHelper.java------给变量赋值
在 loadGlobalSettings(SQLiteDatabase db)方法中：

loadSetting(stmt, Settings.Global.SET_INSTALL_LOCATION, 0);

(3)如何使用：

import android.provider.Settings;

boolean userSetInstLocation = (Settings.Global.getInt(getContentResolver(),
Settings.Global.SET_INSTALL_LOCATION, 0) != 0);

3.我们再以CAR_DOCK_SOUND为例，让我们看看这个变量是如何定义使用的：

(1) frameworks\base\core\java\android\provider\settings.java---定义变量：

public static final String CAR_DOCK_SOUND = "car_dock_sound";
MOVED_TO_GLOBAL.add(Settings.Global.CAR_DOCK_SOUND);

(2) frameworks\base\packages\settingsprovider\src\com\android\providers\settings\ databaseHelper.java------给变量赋值

loadStringSetting(stmt, Settings.Global.CAR_DOCK_SOUND,R.string.def_car_dock_sound);

(3) frameworks\base\packages\settingsprovider\res\values\defaults.xml-----定义初始值

/system/media/audio/ui/Dock.ogg

(4)如何使用：

import android.provider.Settings;

String whichSound = null;
whichSound = Settings.Global.CAR_DOCK_SOUND;
ContentResolver cr = mContext.getContentResolver();
final String soundPath = Settings.Global.getString(cr, whichSound);

4.在DB数据库中添加一个标志位(HY_VIP_FUNCTION)的样例：

(1)在任意APP中使用样例：

int vipFunction = Settings.System.getInt(getContentResolver(), Settings.System.HY_VIP_FUNCTION, -1);

(2)修改的文件：

frameworks\base\packages\settingsprovider\src\com\android\providers\settings\DatabaseHelper.java

    private void loadSystemSettings(SQLiteDatabase db) {
        SQLiteStatement stmt = null;
        try {
            stmt = db.compileStatement("INSERT OR IGNORE INTO system(name,value)"
                    + " VALUES(?,?);");

            loadBooleanSetting(stmt, Settings.System.DIM_SCREEN,
                    R.bool.def_dim_screen);
            loadIntegerSetting(stmt, Settings.System.SCREEN_OFF_TIMEOUT,
                    R.integer.def_screen_off_timeout);

            // Set default cdma DTMF type
            loadSetting(stmt, Settings.System.DTMF_TONE_TYPE_WHEN_DIALING, 0);

            // Set default hearing aid
            loadSetting(stmt, Settings.System.HEARING_AID, 0);

            // Set default tty mode
            loadSetting(stmt, Settings.System.TTY_MODE, 0);

            loadIntegerSetting(stmt, Settings.System.SCREEN_BRIGHTNESS,
                    R.integer.def_screen_brightness);

            loadBooleanSetting(stmt, Settings.System.SCREEN_BRIGHTNESS_MODE,
                    R.bool.def_screen_brightness_automatic_mode);

            loadDefaultAnimationSettings(stmt);

            loadBooleanSetting(stmt, Settings.System.ACCELEROMETER_ROTATION,
                    R.bool.def_accelerometer_rotation);

            loadDefaultHapticSettings(stmt);

            loadBooleanSetting(stmt, Settings.System.NOTIFICATION_LIGHT_PULSE,
                    R.bool.def_notification_pulse);

            loadUISoundEffectsSettings(stmt);

            loadIntegerSetting(stmt, Settings.System.POINTER_SPEED,
                    R.integer.def_pointer_speed);
            
            
            /** Add by HY [wangxianming] add VIP Function in 2014-02-21 by start @{ */
            loadBooleanSetting(stmt, Settings.System.HY_VIP_FUNCTION,
                    R.bool.hy_def_vip_function_value);
            /** Add by HY [wangxianming] add VIP Function in 2014-02-21 by end @} */

frameworks\base\core\java\android\provider\Settings.java

        /**
         * Name of activity to use for wallpaper on the home screen.
         *
         * @deprecated Use {@link WallpaperManager} instead.
         */
        @Deprecated
        public static final String WALLPAPER_ACTIVITY = "wallpaper_activity";

        /**
         * @deprecated Use {@link android.provider.Settings.Global#AUTO_TIME}
         * instead
         */
        @Deprecated
        public static final String AUTO_TIME = Global.AUTO_TIME;

        /**
         * @deprecated Use {@link android.provider.Settings.Global#AUTO_TIME_ZONE}
         * instead
         */
        @Deprecated
        public static final String AUTO_TIME_ZONE = Global.AUTO_TIME_ZONE;

        /**
         * Display times as 12 or 24 hours
         *   12
         *   24
         */
        public static final String TIME_12_24 = "time_12_24";

       
        
      
        
        /** 
         * Add by HY [wangxianming] add VIP Function in 2014-02-21 by start @{
         * 
         * Values 1: is open this function 0: is close this function
         * 
         * @hide
         */ 
        public static final String HY_VIP_FUNCTION = "hy_vip_function"; 
        /** Add by HY [wangxianming] add VIP Function in 2014-02-21 by end @} */

        /**
         * Settings to backup. This is here so that it's in the same place as the settings
         * keys and easy to update.
         *
         * NOTE: Settings are backed up and restored in the order they appear
         *       in this array. If you have one setting depending on another,
         *       make sure that they are ordered appropriately.
         *
         * @hide
         */
        public static final String[] SETTINGS_TO_BACKUP = {
            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,                // moved to global
            MODE_RINGER_STREAMS_AFFECTED,
            MUTE_STREAMS_AFFECTED,
            VOLUME_VOICE,
            VOLUME_SYSTEM,
            VOLUME_RING,
            VOLUME_MUSIC,
            VOLUME_ALARM,
            VOLUME_NOTIFICATION,
            VOLUME_BLUETOOTH_SCO,
            VOLUME_VOICE + APPEND_FOR_LAST_AUDIBLE,
            VOLUME_SYSTEM + APPEND_FOR_LAST_AUDIBLE,
            VOLUME_RING + APPEND_FOR_LAST_AUDIBLE,
            VOLUME_MUSIC + APPEND_FOR_LAST_AUDIBLE,
            VOLUME_ALARM + APPEND_FOR_LAST_AUDIBLE,
            VOLUME_NOTIFICATION + APPEND_FOR_LAST_AUDIBLE,
            VOLUME_BLUETOOTH_SCO + APPEND_FOR_LAST_AUDIBLE,
            TEXT_AUTO_REPLACE,
            TEXT_AUTO_CAPS,
            TEXT_AUTO_PUNCTUATE,
            TEXT_SHOW_PASSWORD,
            AUTO_TIME,                  // moved to global
            AUTO_TIME_ZONE,             // moved to global
            TIME_12_24,
           
            /**  Add by HY [wangxianming] add VIP Function in 2014-02-21 by start @{ */
            HY_VIP_FUNCTION,
            /**  Add by HY [wangxianming] add VIP Function in 2014-02-21 by end @} */
	  					
            DATE_FORMAT,
            HY_WALLPAPER_MODE,
            DTMF_TONE_WHEN_DIALING,
            DTMF_TONE_TYPE_WHEN_DIALING,
            HEARING_AID,
            TTY_MODE,
            SOUND_EFFECTS_ENABLED,
            HAPTIC_FEEDBACK_ENABLED,
            POWER_SOUNDS_ENABLED,       // moved to global
            DOCK_SOUNDS_ENABLED,        // moved to global
            LOCKSCREEN_SOUNDS_ENABLED,
            SHOW_WEB_SUGGESTIONS,
            NOTIFICATION_LIGHT_PULSE,
            SIP_CALL_OPTIONS,
            SIP_RECEIVE_CALLS,
            POINTER_SPEED,
            VIBRATE_WHEN_RINGING
        };

frameworks\base\packages\settingsprovider\res\values\Defaults.xml------http://------------设置初始值

    false

    
    9

    
    true
    -1 		
 	
 	 
 	false
 	

 5.写在后面的话：

      当年，我看到一位大神在framework下添加此例子时，觉得他们好牛啊，在framework下的settings db数据库中都能添加数据，这要写多少代码啊。今天，正好要解一个bug，当我把framework的代码全部导入到source insight中，看了一下这块的代码，觉得添加一个数据在settings模块的db数据库中这也太简单了。

     “绝知此事要躬行”-----这对于程序员来说，确实是一条精辟的古语啊。

      许多时候，对于未知的恐惧和对困难的过大估计，让我们失去了去做事情的勇气。但是，当我们克服问题去亲手把这件事情做完后，我们会发现，原来事实的真像简单的如此让人发紫啊。

6.参考资料：

(1)http://blog.csdn.net/xxxsz/article/details/7480354

SystemProperties与Settings.system