前言
生成的软件识别唯一码想保存到本地，卸载重新安装后根据唯一码进行设备识别。经过查询发现可以使用
Settings系统库简单实现。
使用方法
使用方法类似SharePreference，以键值对key-value的形式进行数据存储，将数据内容保存到系统配置文件中，程序卸载安装不影响系统文件，仍然能获取到之前保存的数据内容。
系统配置文件的路径为：/data/data/com.android.providers.settings/databases/
1. 数据保存：
//设置系统配置文件中的配置数据，第一个参数固定,通过上下文获取ContentResolver，第二个参数是要保存数据的Key值，第三个参数是要保存的数据即value值。
Settings.System.putString(getContentResolver(), "key值", "保存数据value值");
2. 数据获取：
//获取系统配置文件中的数据，第一个参数固定,通过上下文获取ContentResolver，第二个参数是已经保存的数据的Key值，通过key获取对应value值。
String value = Settings.System.getString(getContentResolver(), "key值");
3. 配置清单文件权限及权限获取：
<uses-permission android:name="android.permission.WRITE_SETTINGS"/>
//申请权限
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (!Settings.System.canWrite(context)) {
Intent intent = new Intent(Settings.ACTION_MANAGE_WRITE_SETTINGS);
intent.setData(Uri.parse("package:" + context.getPackageName()));
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
}
系统配置
通过Settings我们还可以修改系统中的默认值，例如修改亮度：
private static final int MIN_SCREEN_TIMEOUT_VALUE = 15000;
//修改系统灭屏时间为15秒
Settings.System.putInt(getApplicationContext().getContentResolver(),"screen_off_timeout", MIN_SCREEN_TIMEOUT_VALUE);
深入了解
<?xml version="1.0" encoding="utf-8"?>
<!--
/**
* 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>
<integer name="def_sleep_timeout">-1</integer>
<bool name="def_airplane_mode_on">false</bool>
<bool name="def_theater_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>
<string name="def_bluetooth_disabled_profiles" translatable="false">0</string>
<bool name="def_auto_time">true</bool>
<bool name="def_auto_time_zone">true</bool>
<bool name="def_accelerometer_rotation">false</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">true</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_wifi_wakeup_enabled">true</bool>
<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>
<!-- 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>
<integer name="def_dock_sounds_enabled_when_accessibility">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_trusted_sound" translatable="false">/system/media/audio/ui/Trusted.ogg</string>
<string name="def_wireless_charging_started_sound" translatable="false">/system/media/audio/ui/WirelessChargingStarted.ogg</string>
<string name="def_charging_started_sound" translatable="false">/system/media/audio/ui/ChargingStarted.ogg</string>
<!-- sound trigger detection service default values -->
<integer name="def_max_sound_trigger_detection_service_ops_per_day" translatable="false">1000</integer>
<integer name="def_sound_trigger_detection_service_op_timeout" translatable="false">15000</integer>
<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.SYNC_PARENT_SOUNDS -->
<bool name="def_sync_parent_sounds">true</bool>
<!-- Default for Settings.Secure.ACCESSIBILITY_SPEAK_PASSWORD -->
<bool name="def_accessibility_speak_password">true</bool>
<!-- 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">400</integer>
<!-- Default for Settings.Secure.MULTI_PRESS_TIMEOUT -->
<integer name="def_multi_press_timeout_millis">300</integer>
<!-- Default for Settings.Secure.SHOW_IME_WITH_HARD_KEYBOARD -->
<bool name="def_show_ime_with_hard_keyboard">false</bool>
<!-- 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>
<!-- Default for UI touch sounds enabled -->
<bool name="def_sound_effects_enabled">true</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>
<!-- Initial value for the Settings.Secure.IMMERSIVE_MODE_CONFIRMATIONS setting,
which is a comma separated list of packages that no longer need confirmation
for immersive mode.
Override to disable immersive mode confirmation for certain packages. -->
<string name="def_immersive_mode_confirmations" translatable="false"></string>
<!-- Default for Settings.Global.WIFI_SCAN_ALWAYS_AVAILABLE -->
<integer name="def_wifi_scan_always_available">0</integer>
<!-- Default for Settings.Secure.LOCK_SCREEN_SHOW_NOTIFICATIONS, 1==on -->
<integer name="def_lock_screen_show_notifications">1</integer>
<!-- Default for Settings.Secure.LOCK_SCREEN_ALLOW_PRIVATE_NOTIFICATIONS -->
<bool name="def_lock_screen_allow_private_notifications">true</bool>
<!-- Default for Settings.Global.HEADS_UP_NOTIFICATIONS_ENABLED, 1==on -->
<integer name="def_heads_up_enabled">1</integer>
<!-- Default for Settings.Global.DEVICE_NAME $1=MANUFACTURER $2=MODEL-->
<string name="def_device_name">%1$s %2$s</string>
<!-- Default for Settings.Global.DEVICE_NAME $1=MODEL-->
<string name="def_device_name_simple">%1$s</string>
<!-- Default for Settings.Secure.WAKE_GESTURE_ENABLED -->
<bool name="def_wake_gesture_enabled">true</bool>
<!-- Default state of tap to wake -->
<bool name="def_double_tap_to_wake">true</bool>
<!-- Default for Settings.Secure.NFC_PAYMENT_COMPONENT -->
<string name="def_nfc_payment_component"></string>
<!-- Default setting for ability to add users from the lock screen -->
<bool name="def_add_users_from_lockscreen">false</bool>
<!-- default setting for Settings.System.END_BUTTON_BEHAVIOR : END_BUTTON_BEHAVIOR_SLEEP -->
<integer name="def_end_button_behavior">0x2</integer>
<!-- default setting for Settings.Global.DEFAULT_RESTRICT_BACKGROUND_DATA -->
<bool name="def_restrict_background_data">false</bool>
<!-- Default for Settings.Secure.BACKUP_MANAGER_CONSTANTS -->
<string name="def_backup_manager_constants"></string>
<!-- Default setting for Settings.Global.MOBILE_DATA_ALWAYS_ON -->
<bool name="def_mobile_data_always_on">true</bool>
<!-- Default for Settings.Secure.BACKUP_LOCAL_TRANSPORT_PARAMETERS -->
<string name="def_backup_local_transport_parameters"></string>
<!-- Default for Settings.Global.ZEN_DURATION
If 0, turning on dnd manually will last indefinitely.
Else if non-negative, turning on dnd manually will last for this many minutes.
Else (if negative), turning on dnd manually will surface a dialog that prompts
user to specify a duration.-->
<integer name="def_zen_duration">0</integer>
<!-- Default for Settings.Global.BACKUP_AGENT_TIMEOUT_PARAMETERS -->
<string name="def_backup_agent_timeout_parameters"></string>
<!-- Default for Settings.System.VIBRATE_WHEN_RINGING -->
<bool name="def_vibrate_when_ringing">false</bool>
</resources>
这些key对应的值，我们可以在/data/data/com.android.providers.settings/databases/settings.db里三个表global, system, secure中进行查看。
自从android 6.0以后这几个表都变为了xml文件，不同用户放不同的路径下，如果没有创建新用户，则在/data/system/users/0下 settings_global.xml, settings_system.xml, settings_secure.xml中。
通过修改文件中配置项对应内容就可以修改系统配置。
更多内容可以访问：
GitHub地址：https://github.com/MickJson
欢迎点击查阅及Star，我也会继续补充其它有用的知识及例子在项目上。
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