Android 11 and above SettingsProvider DatabaseHelper analysis

In the Android operating system, SettingsProvider is a very critical component, which is responsible for storing and managing system and application settings. In this article, I’ll dig into the DatabaseHelper class, which is the core part of the SettingsProvider.

1. What is DatabaseHelper?

DatabaseHelper is a class inherited from SQLiteOpenHelper that is responsible for creating, updating and managing the system settings database. The system settings database is an SQLite database file, which is stored in /data/system/users/0/settings_system.xml, /data/system/users/0/settings_secure.xml, /data/system/users/0/ settings_global.xml path, where user_id is the ID of the current user. The system settings database contains multiple tables, each table corresponds to a type of settings, such as system, secure, global, etc.

2. Main method

2.1 onCreate(SQLiteDatabase db)

This method is called when the database is first created. It is responsible for initializing database tables and default system settings.

@Override
public void onCreate(SQLiteDatabase db) {<!-- -->
    // Create system settings table
    db.execSQL("CREATE TABLE system (" +
            "_id INTEGER PRIMARY KEY AUTOINCREMENT," +
            "name TEXT UNIQUE ON CONFLICT REPLACE," +
            "value TEXT" +
            ");");

    // ... other table creation code ...

    // Initialize default settings
    loadDefaultSystemSettings(db);
}

2.2 onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)

This method will be called when the database version is upgraded. It is responsible for updating the database table structure and data.

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {<!-- -->
    // Perform the corresponding database upgrade operation according to the version number
    if (oldVersion < 2) {<!-- -->
        // ... code to upgrade to version 2 ...
    }
    if (oldVersion < 3) {<!-- -->
        // ... code to upgrade to version 3 ...
    }
    // ... upgrade code for other versions ...
}

3. Data table structure

To better understand DatabaseHelper, you need to understand the structure of the data tables it manages. Here are some main tables:

table name description main field
system Storage system level settings _id, name, value
secure storage Security-related settings _id, name, value
global Store global settings, valid for all users _id, name, value
… … …

4. Initialize default settings

DatabaseHelper is also responsible for loading default system settings. These settings are usually defined in XML resource files and loaded when the database is created.

private void loadDefaultSystemSettings(SQLiteDatabase db) {<!-- -->
    // load default settings from resource file
    ContentValues values = new ContentValues();
    values. put("name", "example_setting_name");
    values. put("value", "example_setting_value");
    db.insert("system", null, values);

    // ... load other default settings ...
}

5. Different Android system version settings storage system location, difference

The settings of Android system are stored in the system partition in the form of SQLite database. The location and structure of the settings database may be different for different Android system versions. Here are some common Android system versions and their settings database locations:

Android version settings database location
Android 4.4 /data/data/com.android.providers.settings/databases/settings.db
Android 5.0 /data/system/ users/0/settings.db
Android 6.0 /data/system/users/0/settings_system.db, /data/system/users/ 0/settings_secure.db, /data/system/users/0/settings_global.db
Android 7.0 ~ /data/system/users/0 /settings_system.xml, /data/system/users/0/settings_secure.xml, /data/system/users/0/settings_global.xml
Android 11.0 /data/system/users/0/settings_system.xml, /data/system/users/0/settings_secure.xml /data/system/users/0/settings_global.xml

As can be seen from the above table, the Android system from version 4.4 to version 6.0 uses the SQLite database to store settings, but reads from different directories. Starting from version 7.0, the Android system uses XML files to store settings, and stores system level, security level, and global level settings separately in different directories.

6. Detailed usage of adb settings command

adb is short for Android Debug Bridge, which is a tool for connecting and controlling Android devices. adb provides a subcommand called settings that can be used to query and modify system and application settings.

The basic syntax of the adb settings command is as follows:

adb shell settings [namespace] [name] [value]

in:

  • namespace refers to the namespace to which the settings to be operated belong, which can be system, secure, global or other application-defined namespaces.
  • name is the name of the setting to operate on.
  • value refers to the value to be set or queried.

For example:

  • Query the screen brightness in system settings:
adb shell settings get system screen_brightness
  • Query the status of airplane mode in global settings:
adb shell settings get global airplane_mode_on

7. How to create a settings variable in the Android system How to initialize

If you want to create a custom settings variable in the Android system, you need to do the following steps:

  • Define a constant in the SettingsContract class as the name of the custom variable. For example:
public static final String MY_SETTING = "my_setting";
  • In the DatabaseHelper class, add a column in the corresponding data table as the storage field of the custom variable. For example:
db.execSQL("ALTER TABLE system ADD COLUMN my_setting TEXT;");
  • In the DatabaseHelper class, in the onCreate method, set a default value for the custom variable. For example:
values.put("name", "my_setting");
values. put("value", "default_value");
db.insert("system", null, values);
  • In the SettingsProvider class, in the call method, add a read-write interface for the custom variable. For example:
case MY_SETTING:
    return getOrPutSetting(uri, db, "system", "my_setting", value);
  • In the Settings class, add a getter and setter method for the custom variable. For example:
public static String getMySetting(ContentResolver cr) {<!-- -->
    return Settings.System.getString(cr, MY_SETTING);
}

public static boolean putMySetting(ContentResolver cr, String value) {<!-- -->
    return Settings.System.putString(cr, MY_SETTING, value);
}

You can use the custom settings variable in the Android system

The following is a table made from the contents of the provided defaults.xml file:

field name value range field meaning
def_dim_screen true, false Whether to reduce screen brightness
def_screen_off_timeout Integer (such as : 60000) Screen off timeout (milliseconds)
def_sleep_timeout integer (eg: -1) Sleep timeout time
def_airplane_mode_on true, false Whether to enable airplane mode
def_theater_mode_on true, false Whether to enable theater mode
def_airplane_mode_radios String (such as: cell, bluetooth, wifi, nfc, wimax) Wireless communication mode that is turned off in airplane mode
airplane_mode_toggleable_radios String (such as: bluetooth,wifi,nfc) Wireless communication methods that can be switched in flight mode
def_bluetooth_disabled_profiles string (eg: 0) Bluetooth configuration to disable by default
def_auto_time true, false Whether to automatically set the time
def_auto_time_zone true, false Whether to automatically set the time zone
def_accelerometer_rotation true, false Whether to allow the accelerometer to rotate the screen
def_screen_brightness Integer (eg: 102) Default screen brightness (0-255)
def_screen_brightness_automatic_mode true, false Whether to automatically adjust the screen brightness
def_window_animation_scale Score (eg: 100%) window animation scaling Scale
def_window_transition_scale Score (eg: 100%) window transition scaling
def_haptic_feedback true, false Whether to enable haptic feedback
def_dock_sounds_enabled_when_accessibility integer (eg: 0) Whether the dock sound is enabled when accessibility is enabled
def_desk_dock_sound String (eg: / product/media/audio/ui/Dock.ogg) Desktop dock sound file path
def_desk_undock_sound String (such as : /product/media/audio/ui/Undock.ogg) Desktop undock sound file path
def_car_dock_sound characters string (such as: /product/media/audio/ui/Dock.ogg) car docking sound file path
def_car_undock_sound String (eg: /product/media/audio/ui/Undock.ogg) Car undock sound file path
def_lockscreen_sounds_enabled Integer (eg: 1) Whether the lock screen sound is enabled
def_lock_sound String (eg: / product/media/audio/ui/Lock.ogg) Lock screen sound file path
def_unlock_sound string (such as : /product/media/audio/ui/Unlock.ogg) Unlock sound file path
def_trusted_sound string( eg: /product/media/audio/ui/Trusted.ogg) Trusted sound file path
def_wireless_charging_started_sound String (such as: /product/media/audio/ui/WirelessChargingStarted.ogg) Wireless charging start sound file path
def_charging_started_sound String (such as: /product/media/audio/ui/ChargingStarted.ogg) Charging start sound file path
def_max_sound_trigger_detection_service_ops_per_day Integer (eg: 1000) The maximum number of operations per day for the sound trigger detection service
def_sound_trigger_detection_service_op_timeout Integer (eg: 15000) Operation timeout of sound trigger detection service
def_lockscreen_disabled true, false Whether to disable the lock screen
def_device_provisioned true, false Is the device provisioned
def_dock_audio_media_enabled Integer (eg: 1) Whether to enable audio media when docked
def_notifications_use_ring_volume true, false Whether the notification uses the ringtone volume
def_vibrate_in_silent true, false Whether to vibrate in silent mode
def_sync_parent_sounds true, false Synchronize parent sound effects
def_accessibility_speak_password true, false Whether the accessibility function reads the password
def_touch_exploration_enabled true, false Whether touch exploration is enabled
def_accessibility_display_magnification_scale Score (eg: 200%) Accessibility display magnification ratio
def_accessibility_display_magnification_enabled true, false Whether to enable accessibility display magnification
def_accessibility_display_magnification_auto_update true, false Accessibility display magnification is automatically updated
def_user_rotation Integer (eg: 0) Default setting for user rotation
def_download_manager_max_bytes_over_mobile Integer ( eg: -1) Maximum bytes to download over mobile data
def_download_manager_recommended_max_bytes_over_mobile integer (eg: -1) Recommended maximum number of bytes to download via mobile data
def_long_press_timeout_millis integer (eg: 400) Long press timeout (milliseconds)
def_multi_press_timeout_millis Integer (eg: 300) Multiple press timeout ( milliseconds)
def_show_ime_with_hard_keyboard true, false Whether to display the input method on the hard keyboard
def_pointer_speed integer (eg: 0) default setting for pointer speed
def_dtmf_tones_enabled true, false Whether DTMF tones are enabled
def_sound_effects_enabled true, false Whether to enable UI touch sound
def_stay_on_while_plugged_in true, false Whether to stay on when plugged in
def_max_dhcp_retries Integer (eg: 9) Maximum number of retries to connect to DHCP
def_user_setup_complete true, false Whether user setup is complete
def_tv_user_setup_complete true, false Whether the TV user setting is completed
def_low_battery_sound_timeout Integer (eg: 0) Low battery sound timeout
def_immersive_mode_confirmations string List of packages that no longer require immersive mode confirmations
def_wifi_scan_always_available integer (eg: 0) Whether Wi-Fi scanning is always available
def_lock_screen_show_notifications Integer (eg: 1) Whether notifications are displayed on the lock screen
def_lock_screen_allow_private_notifications true, false Whether private notifications are allowed on the lock screen
def_heads_up_enabled Integer (eg: 1) Whether to enable Heads Up notifications
def_device_name string (eg: %1

the s

s %2

ss)

 Default device name format
def_device_name_simple String (eg: %1$s) Simple default device name format
def_wake_gesture_enabled true, false Whether to enable wake gesture
def_double_tap_to_wake true, false Whether to enable double-tap to wake
def_nfc_payment_component String Default settings of NFC payment components
def_add_users_from_lockscreen true, false whether Allow adding users from lock screen
def_end_button_behavior Integer (eg: 0x2) End button behavior
def_restrict_background_data true, false Whether to restrict background data
def_backup_manager_constants String Default settings for backup manager constants
def_mobile_data_always_on true, false Whether mobile data is always on
def_backup_local_transport_parameters string Backup default settings for local transport parameters
def_zen_duration Integer (eg: 0) Default duration of Zen mode
def_backup_agent_timeout_parameters string Default setting for backup agent timeout parameter
def_vibrate_when_ringing true, false true, false td>

Whether to vibrate when an incoming call
def_apply_ramping_ringer true, false Whether to apply a gradually increasing ringtone
def_charging_vibration_enabled true, false Whether to vibrate when charging
def_charging_sounds_enabled true, false Whether to play sound when charging
def_notification_bubbles true, false Whether to enable the notification bubble
def_aware_enabled true, false Whether the Aware function is enabled
def_skip_gesture true, false Whether to enable skip gesture
def_silence_gesture true, false Whether mute gesture is enabled
def_aware_lock_enabled true, false Aware lock function Whether to enable
def_hdmiControlAutoDeviceOff true, false Whether the HDMI control automatic device off function is enabled
def_screenshot_button_show Integer (eg: 0) Whether to show the default setting of the screenshot button
def_dock_sounds_enabled_when_accessibility Integer (eg: 0) Whether dock sound is enabled when accessibility is enabled
def_desk_dock_sound String (eg: /product/media/audio/ui/Dock.ogg) Desktop dock sound file path
def_desk_undock_sound String (eg: /product/media/audio/ui/Undock.ogg) Desktop undock sound file path
def_car_dock_sound String (eg: /product/media/audio/ui/Dock.ogg) Car docking sound file path
def_car_undock_sound string (eg: /product/media/audio/ui/Undock.ogg) car undock sound file path
def_lockscreen_sounds_enabled Integer (eg: 1) Whether the lock screen sound is enabled
def_lock_sound String (such as: /product/media/audio/ui/Lock.ogg) Lock screen sound file path
def_unlock_sound String (such as: /product/media/audio/ui/Unlock.ogg) Unlock sound file path
def_trusted_sound String (eg: /product/media/audio/ui/Trusted.ogg) Trusted sound file path
def_wireless_charging_started_sound String (such as: /product/media/audio/ui/WirelessChargingStarted.ogg) Wireless charging start sound file path
def_charging_started_sound string (such as: /product/media/audio/ui/ChargingStarted.ogg) charging start sound file path
def_max_sound_trigger_detection_service_ops_per_day Integer (eg: 1000) The maximum number of operations per day for the sound trigger detection service
def_sound_trigger_detection_service_op_timeout Integer (eg: 15000) Operation timeout of sound trigger detection service
def_lockscreen_disabled true , false Whether to disable the lock screen
def_device_provisioned true, false Whether the device is provisioned
def_dock_audio_media_enabled Integer (eg: 1) Whether to enable audio media when docked
def_notifications_use_ring_volume true, false Whether the notification uses the ring volume
def_vibrate_in_silent true , false Whether to vibrate in silent mode
def_sync_parent_sounds true, false Whether to synchronize parent sound effects
def_accessibility_speak_password true, false Whether the accessibility function reads the password
def_touch_exploration_enabled true, false Whether to enable touch exploration
def_accessibility_display_magnification_scale Score (such as : 200%) Accessibility display magnification ratio
def_accessibility_display_magnification_enabled true, false Whether to enable Accessibility display magnification
def_accessibility_display_magnification_auto_update true, false Whether the accessibility display magnification is automatically updated
def_user_rotation integer (eg: 0) default setting for user rotation
def_download_manager_max_bytes_over_mobile Integer (eg: -1) Maximum bytes to download over mobile data
def_download_manager_recommended_max_bytes_over_mobile Integer (eg: -1) Recommended maximum number of bytes to download via mobile data
def_long_press_timeout_millis Integer (eg: 400) Long press timeout (milliseconds)
def_multi_press_timeout_millis Integer (eg: 300) Multiple pressing timeout (milliseconds)
def_show_ime_with_hard_keyboard true, false Whether to display the input method on the hard keyboard
def_pointer_speed Integer (eg: 0) Default setting for pointer speed
def_dtmf_tones_enabled true, false Whether to enable DTMF tones
def_sound_effects_enabled true, false Whether to enable UI touch sound
def_stay_on_while_plugged_in true, false Whether to stay on when plugged in
def_max_dhcp_retries Integer (eg: 9) Maximum number of retries to connect to DHCP
def_user_setup_complete true, false Whether user setup is complete
def_tv_user_setup_complete true, false Whether the TV user setting is complete
def_low_battery_sound_timeout integer (eg: 0) Low battery sound timeout
def_immersive_mode_confirmations string List of packages that no longer require immersive mode confirmation
def_wifi_scan_always_available integer (e.g. 0) Whether Wi-Fi scan is always available
def_lock_screen_show_notifications Integer (eg: 1) Whether to show notifications on the lock screen
def_lock_screen_allow_private_notifications true, false Whether private notifications are allowed on the lock screen
def_heads_up_enabled Integer (eg: 1) Whether to enable Heads Up notification
def_device_name string (eg: %1

the s

s %2

ss)

 Default device name format
def_device_name_simple String (eg: %1$s) Simple default device name format
def_wake_gesture_enabled true, false Whether to enable wake gesture
def_double_tap_to_wake true, false Whether to enable double-tap to wake
def_nfc_payment_component String Default settings of NFC payment components
def_add_users_from_lockscreen true, false whether Allow adding users from lock screen
def_end_button_behavior Integer (eg: 0x2) End button behavior
def_restrict_background_data true, false Whether to restrict background data
def_backup_manager_constants String Default settings for backup manager constants
def_mobile_data_always_on true, false Whether mobile data is always on
def_backup_local_transport_parameters string Backup default settings for local transport parameters
def_zen_duration Integer (eg: 0) Default duration of Zen mode
def_backup_agent_timeout_parameters string Default setting for backup agent timeout parameter
def_vibrate_when_ringing true, false true, false td>

Whether to vibrate when an incoming call
def_apply_ramping_ringer true, false Whether to apply a gradually increasing ringtone
def_charging_vibration_enabled true, false Whether to vibrate when charging
def_charging_sounds_enabled true, false Whether to play sound when charging
def_notification_bubbles true, false Whether to enable the notification bubble
def_aware_enabled true, false Whether the Aware function is enabled
def_skip_gesture true, false Whether to enable skip gesture
def_silence_gesture true, false Whether mute gesture is enabled
def_aware_lock_enabled true, false Aware lock function Whether to enable
def_hdmiControlAutoDeviceOff true, false Whether the HDMI control automatic device off function is enabled
def_screenshot_button_show Integer (eg: 0) Whether to display the default setting of the screenshot button

Summary

This article introduces the relevant knowledge of SettingsProvider DatabaseHelper above Android 11, including its function, method, data table structure, default settings, differences between different versions, the use of adb commands, the creation of custom variables, etc.

Hope this article can help you better understand Android’s SettingsProvider and DatabaseHelper. Please leave a message if you have any questions or suggestions.