在frameworks中跟Setting默认值相关的几个文件
/frameworks/base/packages/SettingsProvider/res/values/defaults.xml
/frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
在defaults.xml文件中定义了相关的值，DatabaseHelper.java会把相应的值读取出来保存到ContentProvider
下面就来看下defaults.xml中定义了哪些值
<?xml version="1.0" encoding="utf-8"?>上面的xml定义中String有一个属性translatable="false"表示多国语言时不需要进行翻译，这里就不对上面的定义一一解释，只对<string name="def_location_providers_allowed" translatable="false">gps</string>进行分析
<!--
/**
* Copyright (c) 2009, The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
-->
<resources>
<bool name="def_dim_screen">true</bool>
<integer name="def_screen_off_timeout">60000</integer>
<bool name="def_airplane_mode_on">false</bool>
<!-- Comma-separated list of bluetooth, wifi, and cell. -->
<string name="def_airplane_mode_radios" translatable="false">cell,bluetooth,wifi,nfc,wimax</string>
<string name="airplane_mode_toggleable_radios" translatable="false">bluetooth,wifi,nfc</string>
<bool name="def_auto_time">true</bool>
<bool name="def_auto_time_zone">true</bool>
<bool name="def_accelerometer_rotation">true</bool>
<!-- Default screen brightness, from 0 to 255. 102 is 40%. -->
<integer name="def_screen_brightness">102</integer>
<bool name="def_screen_brightness_automatic_mode">false</bool>
<fraction name="def_window_animation_scale">100%</fraction>
<fraction name="def_window_transition_scale">100%</fraction>
<bool name="def_haptic_feedback">true</bool>
<bool name="def_bluetooth_on">false</bool>
<bool name="def_wifi_display_on">false</bool>
<bool name="def_install_non_market_apps">false</bool>
<bool name="def_package_verifier_enable">true</bool>
<!-- Comma-separated list of location providers.
Network location is off by default because it requires
user opt-in via Setup Wizard or Settings.
-->
<string name="def_location_providers_allowed" translatable="false">gps</string>
<bool name="assisted_gps_enabled">true</bool>
<bool name="def_netstats_enabled">true</bool>
<bool name="def_usb_mass_storage_enabled">true</bool>
<bool name="def_wifi_on">false</bool>
<!-- 0 == never, 1 == only when plugged in, 2 == always -->
<integer name="def_wifi_sleep_policy">2</integer>
<bool name="def_networks_available_notification_on">true</bool>
<bool name="def_backup_enabled">false</bool>
<!--string name="def_backup_transport" translatable="false">android/com.android.internal.backup.LocalTransport</string-->
<string name="def_backup_transport" translatable="false">com.google.android.backup/.BackupTransportService</string>
<!-- Default value for whether or not to pulse the notification LED when there is a
pending notification -->
<bool name="def_notification_pulse">true</bool>
<bool name="def_mount_play_notification_snd">true</bool>
<bool name="def_mount_ums_autostart">false</bool>
<bool name="def_mount_ums_prompt">true</bool>
<bool name="def_mount_ums_notify_enabled">true</bool>
<!-- user interface sound effects -->
<integer name="def_power_sounds_enabled">1</integer>
<string name="def_low_battery_sound" translatable="false">/system/media/audio/ui/LowBattery.ogg</string>
<integer name="def_dock_sounds_enabled">0</integer>
<string name="def_desk_dock_sound" translatable="false">/system/media/audio/ui/Dock.ogg</string>
<string name="def_desk_undock_sound" translatable="false">/system/media/audio/ui/Undock.ogg</string>
<string name="def_car_dock_sound" translatable="false">/system/media/audio/ui/Dock.ogg</string>
<string name="def_car_undock_sound" translatable="false">/system/media/audio/ui/Undock.ogg</string>
<integer name="def_lockscreen_sounds_enabled">1</integer>
<string name="def_lock_sound" translatable="false">/system/media/audio/ui/Lock.ogg</string>
<string name="def_unlock_sound" translatable="false">/system/media/audio/ui/Unlock.ogg</string>
<string name="def_wireless_charging_started_sound" translatable="false">/system/media/audio/ui/WirelessChargingStarted.ogg</string>
<bool name="def_lockscreen_disabled">false</bool>
<bool name="def_device_provisioned">false</bool>
<integer name="def_dock_audio_media_enabled">1</integer>
<!-- Notifications use ringer volume -->
<bool name="def_notifications_use_ring_volume">true</bool>
<!-- Default for Settings.System.VIBRATE_IN_SILENT -->
<bool name="def_vibrate_in_silent">true</bool>
<!-- Default for Settings.Secure.ACCESSIBILITY_SCRIPT_INJECTION -->
<bool name="def_accessibility_script_injection">false</bool>
<!-- Default for Settings.Secure.ACCESSIBILITY_SPEAK_PASSWORD -->
<bool name="def_accessibility_speak_password">false</bool>
<!-- Default for Settings.Secure.ACCESSIBILITY_WEB_CONTENT_KEY_BINDINGS -->
<string name="def_accessibility_web_content_key_bindings" translatable="false">
<!-- DPAD/Trackball UP - traverse previous on current axis and send an event. -->
0x13=0x01000100;
<!-- DPAD/Trackball DOWN - traverse next on current axis and send an event. -->
0x14=0x01010100;
<!-- DPAD/Trackball LEFT - traverse previous on the character navigation axis and send event. -->
0x15=0x02000001;
<!-- DPAD/Trackball RIGHT - traverse next on the character navigation axis end send event. -->
0x16=0x02010001;
<!-- Alt+DPAD/Trackball UP - go to the top of the document. -->
0x200000013=0x02000601;
<!-- Alt+DPAD/Trackball DOWN - go to the bottom of the document. -->
0x200000014=0x02010601;
<!-- Alt+DPAD/Trackball LEFT - transition from an axis to another and sends an event.-->
<!-- Axis transitions: 2 -> 1; -->
0x200000015=0x03020101;
<!-- Alt+DPAD/Trackball RIGHT - transition from an axis to another and sends an event. -->
<!-- Axis transitions: 1 -> 2; -->
0x200000016=0x03010201;
<!-- Alt+g - go to the previous heading and send an event. -->
0x200000023=0x02000301;
<!-- Alt+h - go to the next heading and send an event. -->
0x200000024=0x02010301;
<!-- Alt+COMMA - transition to sentence navigation axis and send an event. -->
<!-- Axis transitions: 7 -> 2; -->
0x200000037=0x03070201;
<!-- Alt+PERIOD - transition to default web view behavior axis and send an event. -->
<!-- Axis transitions: 0 -> 7; 1 - > 7; 2 -> 7; -->
0x200000038=0x03000701:0x03010701:0x03020701;
</string>
<!-- Default for Settings.Secure.ACCESSIBILITY_SCRIPT_INJECTION_URL -->
<string name="def_accessibility_screen_reader_url" translatable="false">
https://ssl.gstatic.com/accessibility/javascript/android/AndroidVox_v1.js
</string>
<!-- Default for Settings.Secure.TOUCH_EXPLORATION_ENABLED -->
<bool name="def_touch_exploration_enabled">false</bool>
<!-- Default value for Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_SCALE -->
<fraction name="def_accessibility_display_magnification_scale">200%</fraction>
<!-- Default value for Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_ENABLED -->
<bool name="def_accessibility_display_magnification_enabled">false</bool>
<!-- Default value for Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_AUTO_UPDATE -->
<bool name="def_accessibility_display_magnification_auto_update">true</bool>
<!-- Default for Settings.System.USER_ROTATION -->
<integer name="def_user_rotation">0</integer>
<!-- Default for Settings.Secure.DOWNLOAD_MAX_BYTES_OVER_MOBILE. <=0 if no limit -->
<integer name="def_download_manager_max_bytes_over_mobile">-1</integer>
<!-- Default for Settings.Secure.DOWNLOAD_RECOMMENDED_MAX_BYTES_OVER_MOBILE. <=0 if no limit -->
<integer name="def_download_manager_recommended_max_bytes_over_mobile">-1</integer>
<!-- Default for Settings.Secure.LONG_PRESS_TIMEOUT_MILLIS -->
<integer name="def_long_press_timeout_millis">500</integer>
<!-- Default for Settings.System.POINTER_SPEED -->
<integer name="def_pointer_speed">0</integer>
<!-- Default for DTMF tones enabled -->
<bool name="def_dtmf_tones_enabled">true</bool>
<!-- M: Default for UI touch sounds disabled ,google defaulit is enable -->
<bool name="def_sound_effects_enabled">false</bool>
<!-- Development settings -->
<bool name="def_stay_on_while_plugged_in">false</bool>
<!-- Number of retries for connecting to DHCP.
Value here is the same as WifiStateMachine.DEFAULT_MAX_DHCP_RETRIES -->
<integer name="def_max_dhcp_retries">9</integer>
<!-- Default for Settings.Secure.USER_SETUP_COMPLETE -->
<bool name="def_user_setup_complete">false</bool>
<!-- Default for Settings.Global.LOW_BATTERY_SOUND_TIMEOUT.
0 means no timeout; battery sounds will always play
>0 is milliseconds of screen-off time after which battery sounds will not play -->
<integer name="def_low_battery_sound_timeout">0</integer>
</resources>
在DatabaseHelper.java中有一个函数来加载.xml中的字段
private void loadSecureSettings(SQLiteDatabase db) {
SQLiteStatement stmt = null;
try {
stmt = db.compileStatement("INSERT OR IGNORE INTO secure(name,value)"
+ " VALUES(?,?);");
loadSetting(stmt, Settings.Secure.LOCATION_PROVIDERS_ALLOWED,
mUtils.getStringValue(Settings.Secure.LOCATION_PROVIDERS_ALLOWED, R.string.def_location_providers_allowed));
String wifiWatchList = SystemProperties.get("ro.com.android.wifi-watchlist");
if (!TextUtils.isEmpty(wifiWatchList)) {
loadSetting(stmt, Settings.Secure.WIFI_WATCHDOG_WATCH_LIST, wifiWatchList);
}
// Don't do this. The SystemServer will initialize ADB_ENABLED from a
// persistent system property instead.
loadSetting(stmt, Settings.Secure.ADB_ENABLED, 1);
// Allow mock locations default, based on build
loadSetting(stmt, Settings.Secure.ALLOW_MOCK_LOCATION,
"1".equals(SystemProperties.get("ro.allow.mock.location")) ? 1 : 0);
loadSecure35Settings(stmt);
loadBooleanSetting(stmt, Settings.Secure.MOUNT_PLAY_NOTIFICATION_SND,
R.bool.def_mount_play_notification_snd);
loadBooleanSetting(stmt, Settings.Secure.MOUNT_UMS_AUTOSTART,
R.bool.def_mount_ums_autostart);
loadBooleanSetting(stmt, Settings.Secure.MOUNT_UMS_PROMPT,
R.bool.def_mount_ums_prompt);
loadBooleanSetting(stmt, Settings.Secure.MOUNT_UMS_NOTIFY_ENABLED,
R.bool.def_mount_ums_notify_enabled);
loadBooleanSetting(stmt, Settings.Secure.ACCESSIBILITY_SCRIPT_INJECTION,
R.bool.def_accessibility_script_injection);
loadStringSetting(stmt, Settings.Secure.ACCESSIBILITY_WEB_CONTENT_KEY_BINDINGS,
R.string.def_accessibility_web_content_key_bindings);
loadIntegerSetting(stmt, Settings.Secure.LONG_PRESS_TIMEOUT,
R.integer.def_long_press_timeout_millis);
loadBooleanSetting(stmt, Settings.Secure.TOUCH_EXPLORATION_ENABLED,
R.bool.def_touch_exploration_enabled);
loadBooleanSetting(stmt, Settings.Secure.ACCESSIBILITY_SPEAK_PASSWORD,
R.bool.def_accessibility_speak_password);
loadStringSetting(stmt, Settings.Secure.ACCESSIBILITY_SCREEN_READER_URL,
R.string.def_accessibility_screen_reader_url);
if (SystemProperties.getBoolean("ro.lockscreen.disable.default", false) == true) {
loadSetting(stmt, Settings.System.LOCKSCREEN_DISABLED, "1");
} else {
loadBooleanSetting(stmt, Settings.System.LOCKSCREEN_DISABLED,
R.bool.def_lockscreen_disabled);
}
loadBooleanSetting(stmt, Settings.Secure.SCREENSAVER_ENABLED,
com.android.internal.R.bool.config_dreamsEnabledByDefault);
loadBooleanSetting(stmt, Settings.Secure.SCREENSAVER_ACTIVATE_ON_DOCK,
com.android.internal.R.bool.config_dreamsActivatedOnDockByDefault);
loadBooleanSetting(stmt, Settings.Secure.SCREENSAVER_ACTIVATE_ON_SLEEP,
com.android.internal.R.bool.config_dreamsActivatedOnSleepByDefault);
loadStringSetting(stmt, Settings.Secure.SCREENSAVER_COMPONENTS,
com.android.internal.R.string.config_dreamsDefaultComponent);
loadStringSetting(stmt, Settings.Secure.SCREENSAVER_DEFAULT_COMPONENT,
com.android.internal.R.string.config_dreamsDefaultComponent);
loadBooleanSetting(stmt, Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_ENABLED,
R.bool.def_accessibility_display_magnification_enabled);
loadFractionSetting(stmt, Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_SCALE,
R.fraction.def_accessibility_display_magnification_scale, 1);
loadBooleanSetting(stmt,
Settings.Secure.ACCESSIBILITY_DISPLAY_MAGNIFICATION_AUTO_UPDATE,
R.bool.def_accessibility_display_magnification_auto_update);
loadBooleanSetting(stmt, Settings.Secure.USER_SETUP_COMPLETE,
R.bool.def_user_setup_complete);
mUtils.loadCustomSecureSettings(stmt);
} finally {
if (stmt != null) stmt.close();
}
}
在上面的代码中有
loadSetting(stmt, Settings.Secure.LOCATION_PROVIDERS_ALLOWED,
mUtils.getStringValue(Settings.Secure.LOCATION_PROVIDERS_ALLOWED, R.string.def_location_providers_allowed));去加载字符串，保存到数据库中，数据库名称为：
private static final String DATABASE_NAME = "settings.db";
static String dbNameForUser(final int userHandle) {
// The owner gets the unadorned db name;
if (userHandle == UserHandle.USER_OWNER) {
return DATABASE_NAME;
} else {
// Place the database in the user-specific data tree so that it's
// cleaned up automatically when the user is deleted.
File databaseFile = new File(
Environment.getUserSystemDirectory(userHandle), DATABASE_NAME);
return databaseFile.getPath();
}
}
public DatabaseHelper(Context context, int userHandle) {
super(context, dbNameForUser(userHandle), null, DATABASE_VERSION);
mContext = context;
mUserHandle = userHandle;
}
来看下是如何读取ContentProvider中的数据，在Setting中就可以使用getContentResolver()去查询对应的字段
当然并不是所有的默认值都是通过读取defaults.xml的，也有的是在DatabaseHelper.java中直接设置
如loadSetting(stmt, Settings.Secure.ADB_ENABLED, 1); 这个ADB Debugging开关就是直接在数据库文件中写入的。
关于USB Debugging 开关也可以在systemui的systemui/usb/StorageNotification.java文件中去设置，可以判断是否有IMEI号
分析代码时如果发现在defaults.xml找不到这一项就直接在DatabaseHelper.java文件中查找。