Class Settings

java.lang.Object
org.javagi.base.ProxyInstance
org.gnome.gobject.TypeInstance
org.gnome.gobject.GObject
org.gnome.gio.Settings
All Implemented Interfaces:
Proxy
@Generated("org.javagi.JavaGI") public class Settings extends GObject

The GSettings class provides a convenient API for storing and retrieving application settings.

Reads and writes can be considered to be non-blocking. Reading settings with GSettings is typically extremely fast: on approximately the same order of magnitude (but slower than) a GLib.HashTable lookup. Writing settings is also extremely fast in terms of time to return to your application, but can be extremely expensive for other threads and other processes. Many settings backends (including dconf) have lazy initialisation which means in the common case of the user using their computer without modifying any settings a lot of work can be avoided. For dconf, the D-Bus service doesn’t even need to be started in this case. For this reason, you should only ever modify GSettings keys in response to explicit user action. Particular care should be paid to ensure that modifications are not made during startup — for example, when setting the initial value of preferences widgets. The built-in bind(String, GObject, String, Set) functionality is careful not to write settings in response to notify signals as a result of modifications that it makes to widgets.

When creating a GSettings instance, you have to specify a schema that describes the keys in your settings and their types and default values, as well as some other information.

Normally, a schema has a fixed path that determines where the settings are stored in the conceptual global tree of settings. However, schemas can also be ‘relocatable’, i.e. not equipped with a fixed path. This is useful e.g. when the schema describes an ‘account’, and you want to be able to store a arbitrary number of accounts.

Paths must start with and end with a forward slash character (/) and must not contain two sequential slash characters. Paths should be chosen based on a domain name associated with the program or library to which the settings belong. Examples of paths are /org/gtk/settings/file-chooser/ and /ca/desrt/dconf-editor/. Paths should not start with /apps/, /desktop/ or /system/ as they often did in GConf.

Unlike other configuration systems (like GConf), GSettings does not restrict keys to basic types like strings and numbers. GSettings stores values as GLib.Variant, and allows any GLib.VariantType for keys. Key names are restricted to lowercase characters, numbers and -. Furthermore, the names must begin with a lowercase character, must not end with a -, and must not contain consecutive dashes.

Similar to GConf, the default values in GSettings schemas can be localized, but the localized values are stored in gettext catalogs and looked up with the domain that is specified in the gettext-domain attribute of the <schemalist> or <schema> elements and the category that is specified in the l10n attribute of the <default> element. The string which is translated includes all text in the <default> element, including any surrounding quotation marks.

The l10n attribute must be set to messages or time, and sets the locale category for translation. The messages category should be used by default; use time for translatable date or time formats. A translation comment can be added as an XML comment immediately above the <default> element — it is recommended to add these comments to aid translators understand the meaning and implications of the default value. An optional translation context attribute can be set on the <default> element to disambiguate multiple defaults which use the same string.

For example:

 <!-- Translators: A list of words which are not allowed to be typed, in
      GVariant serialization syntax.
      See: https://developer.gnome.org/glib/stable/gvariant-text.html -->
 <default l10n='messages' context='Banned words'>['bad', 'words']</default>

Translations of default values must remain syntactically valid serialized GLib.Variants (e.g. retaining any surrounding quotation marks) or runtime errors will occur.

GSettings uses schemas in a compact binary form that is created by the glib-compile-schemas utility. The input is a schema description in an XML format.

A DTD for the gschema XML format can be found here: gschema.dtd

The glib-compile-schemas tool expects schema files to have the extension .gschema.xml.

At runtime, schemas are identified by their ID (as specified in the id attribute of the <schema> element). The convention for schema IDs is to use a dotted name, similar in style to a D-Bus bus name, e.g. org.gnome.SessionManager. In particular, if the settings are for a specific service that owns a D-Bus bus name, the D-Bus bus name and schema ID should match. For schemas which deal with settings not associated with one named application, the ID should not use StudlyCaps, e.g. org.gnome.font-rendering.

In addition to GLib.Variant types, keys can have types that have enumerated types. These can be described by a <choice>, <enum> or <flags> element, as seen in the second example below. The underlying type of such a key is string, but you can use getEnum(String), setEnum(String, int), getFlags(String), setFlags(String, int) access the numeric values corresponding to the string value of enum and flags keys.

An example for default value:

<schemalist>
  <schema id="org.gtk.Test" path="/org/gtk/Test/" gettext-domain="test">

    <key name="greeting" type="s">
      <default l10n="messages">"Hello, earthlings"</default>
      <summary>A greeting</summary>
      <description>
        Greeting of the invading martians
      </description>
    </key>

    <key name="box" type="(ii)">
      <default>(20,30)</default>
    </key>

    <key name="empty-string" type="s">
      <default>""</default>
      <summary>Empty strings have to be provided in GVariant form</summary>
    </key>

  </schema>
</schemalist>

An example for ranges, choices and enumerated types:

<schemalist>

  <enum id="org.gtk.Test.myenum">
    <value nick="first" value="1"/>
    <value nick="second" value="2"/>
  </enum>

  <flags id="org.gtk.Test.myflags">
    <value nick="flag1" value="1"/>
    <value nick="flag2" value="2"/>
    <value nick="flag3" value="4"/>
  </flags>

  <schema id="org.gtk.Test">

    <key name="key-with-range" type="i">
      <range min="1" max="100"/>
      <default>10</default>
    </key>

    <key name="key-with-choices" type="s">
      <choices>
        <choice value='Elisabeth'/>
        <choice value='Annabeth'/>
        <choice value='Joe'/>
      </choices>
      <aliases>
        <alias value='Anna' target='Annabeth'/>
        <alias value='Beth' target='Elisabeth'/>
      </aliases>
      <default>'Joe'</default>
    </key>

    <key name='enumerated-key' enum='org.gtk.Test.myenum'>
      <default>'first'</default>
    </key>

    <key name='flags-key' flags='org.gtk.Test.myflags'>
      <default>["flag1","flag2"]</default>
    </key>
  </schema>
</schemalist>

Vendor overrides

Default values are defined in the schemas that get installed by an application. Sometimes, it is necessary for a vendor or distributor to adjust these defaults. Since patching the XML source for the schema is inconvenient and error-prone, glib-compile-schemas reads so-called ‘vendor override’ files. These are keyfiles in the same directory as the XML schema sources which can override default values. The schema ID serves as the group name in the key file, and the values are expected in serialized GLib.Variant form, as in the following example:

[org.gtk.Example]
key1='string'
key2=1.5

glib-compile-schemas expects schema files to have the extension .gschema.override.

Delay-apply mode

By default, values set on a Settings instance immediately start to be written to the backend (although these writes may not complete by the time that set(String, String, Object...)) returns; see sync()).

In order to allow groups of settings to be changed simultaneously and atomically, GSettings also supports a ‘delay-apply’ mode. In this mode, updated values are kept locally in the Settings instance until they are explicitly applied by calling apply().

For example, this could be useful for a preferences dialog where the preferences all need to be applied simultaneously when the user clicks ‘Save’.

Switching a Settings instance to ‘delay-apply’ mode is a one-time irreversible operation: from that point onwards, all changes made to that Settings have to be explicitly applied by calling apply(). The ‘delay-apply’ mode is also propagated to any child settings objects subsequently created using getChild(String).

At any point, the set of unapplied changes can be queried using Gio.Settings:has-unapplied, and discarded by calling revert().

Binding

A very convenient feature of GSettings lets you bind GObject properties directly to settings, using bind(String, GObject, String, Set). Once a GObject property has been bound to a setting, changes on either side are automatically propagated to the other side. GSettings handles details like mapping between GObject and GLib.Variant types, and preventing infinite cycles.

This makes it very easy to hook up a preferences dialog to the underlying settings. To make this even more convenient, GSettings looks for a boolean property with the name sensitivity and automatically binds it to the writability of the bound setting. If this ‘magic’ gets in the way, it can be suppressed with the G_SETTINGS_BIND_NO_SENSITIVITY flag.

Relocatable schemas

A relocatable schema is one with no path attribute specified on its <schema> element. By using withPath(String, String), a GSettings object can be instantiated for a relocatable schema, assigning a path to the instance. Paths passed to withPath(String, String) will typically be constructed dynamically from a constant prefix plus some form of instance identifier; but they must still be valid GSettings paths. Paths could also be constant and used with a globally installed schema originating from a dependency library.

For example, a relocatable schema could be used to store geometry information for different windows in an application. If the schema ID was org.foo.MyApp.Window, it could be instantiated for paths /org/foo/MyApp/main/, /org/foo/MyApp/document-1/, /org/foo/MyApp/document-2/, etc. If any of the paths are well-known they can be specified as <child> elements in the parent schema, e.g.:

<schema id="org.foo.MyApp" path="/org/foo/MyApp/">
  <child name="main" schema="org.foo.MyApp.Window"/>
</schema>

Build system integration

Meson

GSettings is natively supported by Meson’s GNOME module.

You can install the schemas as any other data file:

install_data(
  'org.foo.MyApp.gschema.xml',
  install_dir: get_option('datadir') / 'glib-2.0/schemas',
)

You can use gnome.post_install() function to compile the schemas on installation:

gnome = import('gnome')
gnome.post_install(
  glib_compile_schemas: true,
)

If an enumerated type defined in a C header file is to be used in a GSettings schema, it can either be defined manually using an <enum> element in the schema XML, or it can be extracted automatically from the C header. This approach is preferred, as it ensures the two representations are always synchronised. To do so, you will need to use the gnome.mkenums() function with the following templates:

schemas_enums = gnome.mkenums('org.foo.MyApp.enums.xml',
  comments: '<!-- @comment@ -->',
  fhead: '<schemalist>',
  vhead: '  <@type@ id="org.foo.MyApp.@EnumName@">',
  vprod: '    <value nick="@valuenick@" value="@valuenum@"/>',
  vtail: '  </@type@>',
  ftail: '</schemalist>',
  sources: enum_sources,
  install_header: true,
  install_dir: get_option('datadir') / 'glib-2.0/schemas',
)

It is recommended to validate your schemas as part of the test suite for your application:

test('validate-schema',
  find_program('glib-compile-schemas'),
  args: ['--strict', '--dry-run', meson.current_source_dir()],
)

If your application allows running uninstalled, you should also use the gnome.compile_schemas() function to compile the schemas in the current build directory:

gnome.compile_schemas()

Autotools

GSettings comes with autotools integration to simplify compiling and installing schemas. To add GSettings support to an application, add the following to your configure.ac:

GLIB_GSETTINGS

In the appropriate Makefile.am, use the following snippet to compile and install the named schema:

gsettings_SCHEMAS = org.foo.MyApp.gschema.xml
EXTRA_DIST = $(gsettings_SCHEMAS)

@GSETTINGS_RULES@

If an enumerated type defined in a C header file is to be used in a GSettings schema, it can either be defined manually using an <enum> element in the schema XML, or it can be extracted automatically from the C header. This approach is preferred, as it ensures the two representations are always synchronised. To do so, add the following to the relevant Makefile.am:

gsettings_ENUM_NAMESPACE = org.foo.MyApp
gsettings_ENUM_FILES = my-app-enums.h my-app-misc.h

gsettings_ENUM_NAMESPACE specifies the schema namespace for the enum files, which are specified in gsettings_ENUM_FILES. This will generate a org.foo.MyApp.enums.xml file containing the extracted enums, which will be automatically included in the schema compilation, install and uninstall rules. It should not be committed to version control or included in EXTRA_DIST.

Localization

No changes are needed to the build system to mark a schema XML file for translation. Assuming it sets the gettext-domain attribute, a schema may be marked for translation by adding it to POTFILES.in, assuming gettext 0.19 or newer is in use (the preferred method for translation):

data/org.foo.MyApp.gschema.xml

Alternatively, if intltool 0.50.1 is in use:

[type: gettext/gsettings]data/org.foo.MyApp.gschema.xml

GSettings will use gettext to look up translations for the <summary> and <description> elements, and also any <default> elements which have a l10n attribute set.

Translations must not be included in the .gschema.xml file by the build system, for example by using a rule to generate the XML file from a template.

  • Constructor Details

    • Settings

      public Settings(MemorySegment address)
      Create a Settings instance for the provided memory address.
      Parameters:
      address - the memory address of the native object

    • Settings

      public Settings(String schemaId)

      Creates a new Settings object with the schema specified by schemaId.

      It is an error for the schema to not exist: schemas are an essential part of a program, as they provide type information. If schemas need to be dynamically loaded (for example, from an optional runtime dependency), SettingsSchemaSource.lookup(String, boolean) can be used to test for their existence before loading them.

      Signals on the newly created Settings object will be dispatched via the thread-default GLib.MainContext in effect at the time of the call to Settings(). The new Settings will hold a reference on the context. See MainContext#pushThreadDefault.

      Parameters:
      schemaId - the ID of the schema
      Since:
      2.26

    • Settings

      public Settings()
      Create a new Settings.

  • Method Details

    • getType

      public static @Nullable Type getType()
      Get the GType of the Settings class.
      Returns:
      the GType

    • getMemoryLayout

      public static MemoryLayout getMemoryLayout()
      The memory layout of the native struct.
      Returns:
      the memory layout

    • asParent

      protected Settings asParent()
      Return this instance as if it were its parent type. Comparable to the Java super keyword, but ensures the parent typeclass is also used in native code.
      Overrides:
      asParent in class GObject
      Returns:
      the instance as if it were its parent type

    • full

      public static Settings full(SettingsSchema schema, @Nullable SettingsBackend backend, @Nullable String path)

      Creates a new Settings object with a given schema, backend and path.

      It should be extremely rare that you ever want to use this function. It is made available for advanced use-cases (such as plugin systems that want to provide access to schemas loaded from custom locations, etc).

      At the most basic level, a Settings object is a pure composition of four things: a Gio.SettingsSchema, a SettingsBackend, a path within that backend, and a GLib.MainContext to which signals are dispatched.

      This constructor therefore gives you full control over constructing Settings instances. The first 3 parameters are given directly as schema, backend and path, and the main context is taken from the thread-default (as per Settings()).

      If backend is NULL then the default backend is used.

      If path is NULL then the path from the schema is used. It is an error if path is NULL and the schema has no path of its own or if path is non-NULL and not equal to the path that the schema does have.

      Parameters:
      schema - the schema describing the settings
      backend - the settings backend to use
      path - the path to use
      Returns:
      a new Settings object
      Since:
      2.32

    • withBackend

      public static Settings withBackend(String schemaId, SettingsBackend backend)

      Creates a new Settings object with the schema specified by schemaId and a given SettingsBackend.

      Creating a Settings object with a different backend allows accessing settings from a database other than the usual one. For example, it may make sense to pass a backend corresponding to the ‘defaults’ settings database on the system to get a settings object that modifies the system default settings instead of the settings for this user.

      Parameters:
      schemaId - the ID of the schema
      backend - the settings backend to use
      Returns:
      a new Settings object
      Since:
      2.26

    • withBackendAndPath

      public static Settings withBackendAndPath(String schemaId, SettingsBackend backend, String path)

      Creates a new Settings object with the schema specified by schemaId and a given SettingsBackend and path.

      This is a mix of withBackend(String, SettingsBackend) and withPath(String, String).

      Parameters:
      schemaId - the ID of the schema
      backend - the settings backend to use
      path - the path to use
      Returns:
      a new Settings object
      Since:
      2.26

    • withPath

      public static Settings withPath(String schemaId, String path)

      Creates a new Settings object with the relocatable schema specified by schemaId and a given path.

      You only need to do this if you want to directly create a settings object with a schema that doesn’t have a specified path of its own. That’s quite rare.

      It is a programmer error to call this function for a schema that has an explicitly specified path.

      It is a programmer error if path is not a valid path. A valid path begins and ends with / and does not contain two consecutive / characters.

      Parameters:
      schemaId - the ID of the schema
      path - the path to use
      Returns:
      a new Settings object
      Since:
      2.26

    • listRelocatableSchemas

      @Deprecated public static String[] listRelocatableSchemas()
      Deprecated.
      Use g_settings_schema_source_list_schemas() instead
      Deprecated.
      Returns:
      a list of relocatable GSettings schemas that are available, in no defined order. The list must not be modified or freed.
      Since:
      2.28

    • listSchemas

      @Deprecated public static String[] listSchemas()
      Deprecated.
      Use g_settings_schema_source_list_schemas() instead. If you used g_settings_list_schemas() to check for the presence of a particular schema, use g_settings_schema_source_lookup() instead of your whole loop.
      Deprecated.
      Returns:
      a list of GSettings schemas that are available, in no defined order. The list must not be modified or freed.
      Since:
      2.26

    • sync

      public static void sync()

      Ensures that all pending operations are complete for the default backend.

      Writes made to a Settings are handled asynchronously. For this reason, it is very unlikely that the changes have it to disk by the time set(String, String, Object...) returns.

      This call will block until all of the writes have made it to the backend. Since the main loop is not running, no change notifications will be dispatched during this call (but some may be queued by the time the call is done).

    • unbind

      public static void unbind(GObject object, String property)

      Removes an existing binding for property on object.

      Note that bindings are automatically removed when the object is finalized, so it is rarely necessary to call this function.

      Parameters:
      object - the object with property to unbind
      property - the property whose binding is removed
      Since:
      2.26

    • apply

      public void apply()

      Applies any changes that have been made to the settings.

      This function does nothing unless this Settings is in ‘delay-apply’ mode. In the normal case settings are always applied immediately.

    • bind

      public void bind(String key, GObject object, String property, Set<SettingsBindFlags> flags)

      Create a binding between the key in the this Settings object and the property property of object.

      The binding uses the default GIO mapping functions to map between the settings and property values. These functions handle booleans, numeric types and string types in a straightforward way. Use bindWithMapping(String, GObject, String, Set, Closure, Closure) if you need a custom mapping, or map between types that are not supported by the default mapping functions.

      Unless the flags include Gio.SettingsBindFlags.NO_SENSITIVITY, this function also establishes a binding between the writability of key and the sensitive property of object (if object has a boolean property by that name). See bindWritable(String, GObject, String, boolean) for more details about writable bindings.

      Note that the lifecycle of the binding is tied to object, and that you can have only one binding per object property. If you bind the same property twice on the same object, the second binding overrides the first one.

      Parameters:
      key - the key to bind
      object - the object with property to bind
      property - the name of the property to bind
      flags - flags for the binding
      Since:
      2.26

    • bind

      public void bind(String key, GObject object, String property, SettingsBindFlags... flags)

      Create a binding between the key in the this Settings object and the property property of object.

      The binding uses the default GIO mapping functions to map between the settings and property values. These functions handle booleans, numeric types and string types in a straightforward way. Use bindWithMapping(String, GObject, String, Set, Closure, Closure) if you need a custom mapping, or map between types that are not supported by the default mapping functions.

      Unless the flags include Gio.SettingsBindFlags.NO_SENSITIVITY, this function also establishes a binding between the writability of key and the sensitive property of object (if object has a boolean property by that name). See bindWritable(String, GObject, String, boolean) for more details about writable bindings.

      Note that the lifecycle of the binding is tied to object, and that you can have only one binding per object property. If you bind the same property twice on the same object, the second binding overrides the first one.

      Parameters:
      key - the key to bind
      object - the object with property to bind
      property - the name of the property to bind
      flags - flags for the binding
      Since:
      2.26

    • bindWithMapping

      public void bindWithMapping(String key, GObject object, String property, Set<SettingsBindFlags> flags, @Nullable Closure getMapping, @Nullable Closure setMapping)
      Version of bindWithMapping(String, GObject, String, Set, Closure, Closure) using closures instead of callbacks for easier binding in other languages.
      Parameters:
      key - the key to bind
      object - the object with property to bind
      property - the name of the property to bind
      flags - flags for the binding
      getMapping - a function that gets called to convert values from this Settings to object, or NULL to use the default GIO mapping
      setMapping - a function that gets called to convert values from object to settings, or NULL to use the default GIO mapping
      Since:
      2.82

    • bindWithMapping

      public void bindWithMapping(String key, GObject object, String property, SettingsBindFlags flags, @Nullable Closure getMapping, @Nullable Closure setMapping)
      Version of bindWithMapping(String, GObject, String, Set, Closure, Closure) using closures instead of callbacks for easier binding in other languages.
      Parameters:
      key - the key to bind
      object - the object with property to bind
      property - the name of the property to bind
      flags - flags for the binding
      getMapping - a function that gets called to convert values from this Settings to object, or NULL to use the default GIO mapping
      setMapping - a function that gets called to convert values from object to settings, or NULL to use the default GIO mapping
      Since:
      2.82

    • bindWritable

      public void bindWritable(String key, GObject object, String property, boolean inverted)

      Create a binding between the writability of key in the this Settings object and the property property of object.

      The property must be boolean; sensitive or visible properties of widgets are the most likely candidates.

      Writable bindings are always uni-directional; changes of the writability of the setting will be propagated to the object property, not the other way.

      When the inverted argument is true, the binding inverts the value as it passes from the setting to the object, i.e. property will be set to true if the key is not writable.

      Note that the lifecycle of the binding is tied to object, and that you can have only one binding per object property. If you bind the same property twice on the same object, the second binding overrides the first one.

      Parameters:
      key - the key to bind
      object - the object with property to bind
      property - the name of a boolean property to bind
      inverted - whether to ‘invert’ the value
      Since:
      2.26

    • createAction

      public Action createAction(String key)

      Creates a Action corresponding to a given Settings key.

      The action has the same name as the key.

      The value of the key becomes the state of the action and the action is enabled when the key is writable. Changing the state of the action results in the key being written to. Changes to the value or writability of the key cause appropriate change notifications to be emitted for the action.

      For boolean-valued keys, action activations take no parameter and result in the toggling of the value. For all other types, activations take the new value for the key (which must have the correct type).

      Parameters:
      key - the name of a key in this Settings
      Returns:
      a new Action
      Since:
      2.32

    • delay

      public void delay()

      Changes the Settings object into ‘delay-apply’ mode.

      In this mode, changes to this Settings are not immediately propagated to the backend, but kept locally until apply() is called.

      Since:
      2.26

    • get

      public void get(String key, String format, Object... varargs)

      Gets the value that is stored at key in settings.

      A convenience function that combines getValue(String) with Variant#get.

      It is a programmer error to give a key that isn’t contained in the schema for this Settings or for the GLib.VariantType of format to mismatch the type given in the schema.

      Parameters:
      key - the key to get the value for
      format - a GLib.Variant format string
      varargs - arguments as per format
      Since:
      2.26

    • getBoolean

      public boolean getBoolean(String key)

      Gets the value that is stored at key in settings.

      A convenience variant of get(String, String, Object...) for booleans.

      It is a programmer error to give a key that isn’t specified as having a b type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to get the value for
      Returns:
      a boolean
      Since:
      2.26

    • getChild

      public Settings getChild(String name)

      Creates a child settings object which has a base path of base-path/name, where base-path is the base path of this Settings and name is as specified by the caller.

      The schema for the child settings object must have been declared in the schema of this Settings using a <child> element.

      The created child settings object will inherit the Gio.Settings:delay-apply mode from settings.

      Parameters:
      name - the name of the child schema
      Returns:
      a ‘child’ settings object
      Since:
      2.26

    • getDefaultValue

      public @Nullable Variant getDefaultValue(String key)

      Gets the ‘default value’ of a key.

      This is the value that would be read if reset(String) were to be called on the key.

      Note that this may be a different value than returned by SettingsSchemaKey.getDefaultValue() if the system administrator has provided a default value.

      Comparing the return values of getDefaultValue(String) and getValue(String) is not sufficient for determining if a value has been set because the user may have explicitly set the value to something that happens to be equal to the default. The difference here is that if the default changes in the future, the user’s key will still be set.

      This function may be useful for adding an indication to a UI of what the default value was before the user set it.

      It is a programmer error to give a key that isn’t contained in the schema for settings.

      Parameters:
      key - the key to get the default value for
      Returns:
      the default value
      Since:
      2.40

    • getDouble

      public double getDouble(String key)

      Gets the value that is stored at key in settings.

      A convenience variant of get(String, String, Object...) for doubles.

      It is a programmer error to give a key that isn’t specified as having a d type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to get the value for
      Returns:
      a double
      Since:
      2.26

    • getEnum

      public int getEnum(String key)

      Gets the value that is stored in this Settings for key and converts it to the enum value that it represents.

      In order to use this function the type of the value must be a string and it must be marked in the schema file as an enumerated type.

      It is a programmer error to give a key that isn’t contained in the schema for this Settings or is not marked as an enumerated type.

      If the value stored in the configuration database is not a valid value for the enumerated type then this function will return the default value.

      Parameters:
      key - the key to get the value for
      Returns:
      the enum value
      Since:
      2.26

    • getFlags

      public int getFlags(String key)

      Gets the value that is stored in this Settings for key and converts it to the flags value that it represents.

      In order to use this function the type of the value must be an array of strings and it must be marked in the schema file as a flags type.

      It is a programmer error to give a key that isn’t contained in the schema for this Settings or is not marked as a flags type.

      If the value stored in the configuration database is not a valid value for the flags type then this function will return the default value.

      Parameters:
      key - the key to get the value for
      Returns:
      the flags value
      Since:
      2.26

    • getHasUnapplied

      public boolean getHasUnapplied()

      Returns whether the Settings object has any unapplied changes.

      This can only be the case if it is in ‘delay-apply’ mode.

      Returns:
      true if this Settings has unapplied changes, false otherwise
      Since:
      2.26

    • getInt

      public int getInt(String key)

      Gets the value that is stored at key in settings.

      A convenience variant of get(String, String, Object...) for 32-bit integers.

      It is a programmer error to give a key that isn’t specified as having an i type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to get the value for
      Returns:
      an integer
      Since:
      2.26

    • getInt64

      public long getInt64(String key)

      Gets the value that is stored at key in settings.

      A convenience variant of get(String, String, Object...) for 64-bit integers.

      It is a programmer error to give a key that isn’t specified as having an x type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to get the value for
      Returns:
      a 64-bit integer
      Since:
      2.50

    • getMapped

      public @Nullable MemorySegment getMapped(String key, @Nullable SettingsGetMapping mapping)

      Gets the value that is stored at key in settings, subject to application-level validation/mapping.

      You should use this function when the application needs to perform some processing on the value of the key (for example, parsing). The mapping function performs that processing. If the function indicates that the processing was unsuccessful (due to a parse error, for example) then the mapping is tried again with another value.

      This allows a robust ‘fall back to defaults’ behaviour to be implemented somewhat automatically.

      The first value that is tried is the user’s setting for the key. If the mapping function fails to map this value, other values may be tried in an unspecified order (system or site defaults, translated schema default values, untranslated schema default values, etc).

      If the mapping function fails for all possible values, one additional attempt is made: the mapping function is called with a NULL value. If the mapping function still indicates failure at this point then the application will be aborted.

      The result parameter for the mapping function is pointed to a gpointer which is initially set to NULL. The same pointer is given to each invocation of mapping. The final value of that gpointer is what is returned by this function. NULL is valid; it is returned just as any other value would be.

      Parameters:
      key - the key to get the value for
      mapping - the function to map the value in the settings database to the value used by the application
      Returns:
      the result, which may be NULL

    • getRange

      @Deprecated public Variant getRange(String key)
      Deprecated.
      Use SettingsSchemaKey.getRange() instead.
      Queries the range of a key.
      Parameters:
      key - the key to query the range of
      Since:
      2.28

    • getString

      public String getString(String key)

      Gets the value that is stored at key in settings.

      A convenience variant of get(String, String, Object...) for strings.

      It is a programmer error to give a key that isn’t specified as having an s type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to get the value for
      Returns:
      a newly-allocated string
      Since:
      2.26

    • getStrv

      public String[] getStrv(String key)

      A convenience variant of get(String, String, Object...) for string arrays.

      It is a programmer error to give a key that isn’t specified as having an as type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to get the value for
      Returns:
      a newly-allocated, NULL-terminated array of strings, the value that is stored at key in settings.
      Since:
      2.26

    • getUint

      public int getUint(String key)

      Gets the value that is stored at key in settings.

      A convenience variant of get(String, String, Object...) for 32-bit unsigned integers.

      It is a programmer error to give a key that isn’t specified as having a u type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to get the value for
      Returns:
      an unsigned integer
      Since:
      2.30

    • getUint64

      public long getUint64(String key)

      Gets the value that is stored at key in settings.

      A convenience variant of get(String, String, Object...) for 64-bit unsigned integers.

      It is a programmer error to give a key that isn’t specified as having a t type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to get the value for
      Returns:
      a 64-bit unsigned integer
      Since:
      2.50

    • getUserValue

      public @Nullable Variant getUserValue(String key)

      Checks the ‘user value’ of a key, if there is one.

      The user value of a key is the last value that was set by the user.

      After calling reset(String) this function should always return NULL (assuming something is not wrong with the system configuration).

      It is possible that getValue(String) will return a different value than this function. This can happen in the case that the user set a value for a key that was subsequently locked down by the system administrator — this function will return the user’s old value.

      This function may be useful for adding a ‘reset’ option to a UI or for providing indication that a particular value has been changed.

      It is a programmer error to give a key that isn’t contained in the schema for settings.

      Parameters:
      key - the key to get the user value for
      Returns:
      the user’s value, if set
      Since:
      2.40

    • getValue

      public Variant getValue(String key)

      Gets the value that is stored in this Settings for key.

      It is a programmer error to give a key that isn’t contained in the schema for settings.

      Parameters:
      key - the key to get the value for
      Returns:
      a new GLib.Variant
      Since:
      2.26

    • isWritable

      public boolean isWritable(String name)
      Finds out if a key can be written.
      Parameters:
      name - the name of a key
      Returns:
      true if the key name is writable, false otherwise
      Since:
      2.26

    • listChildren

      public String[] listChildren()

      Gets the list of children on settings.

      The list is exactly the list of strings for which it is not an error to call getChild(String).

      There is little reason to call this function from ‘normal’ code, since you should already know what children are in your schema. This function may still be useful there for introspection reasons, however.

      You should free the return value with GLib#strfreev when you are done with it.

      Returns:
      a list of the children on settings, in no defined order

    • listKeys

      @Deprecated public String[] listKeys()
      Deprecated.
      Use SettingsSchema.listKeys() instead.

      Introspects the list of keys on settings.

      You should probably not be calling this function from ‘normal’ code (since you should already know what keys are in your schema). This function is intended for introspection reasons.

      You should free the return value with GLib#strfreev when you are done with it.

      Returns:
      a list of the keys on settings, in no defined order

    • rangeCheck

      @Deprecated public boolean rangeCheck(String key, Variant value)
      Deprecated.
      Use SettingsSchemaKey.rangeCheck(Variant) instead.
      Checks if the given value is of the correct type and within the permitted range for key.
      Parameters:
      key - the key to check
      value - the value to check
      Returns:
      true if value is valid for key, false otherwise
      Since:
      2.28

    • reset

      public void reset(String key)

      Resets key to its default value.

      This call resets the key, as much as possible, to its default value. That might be the value specified in the schema or the one set by the administrator.

      Parameters:
      key - the name of a key

    • revert

      public void revert()

      Reverts all unapplied changes to the settings.

      This function does nothing unless this Settings is in ‘delay-apply’ mode. In the normal case settings are always applied immediately.

      Change notifications will be emitted for affected keys.

    • set

      public boolean set(String key, String format, Object... varargs)

      Sets key in this Settings to value.

      A convenience function that combines setValue(String, Variant) with Variant(String, Object...).

      It is a programmer error to give a key that isn’t contained in the schema for this Settings or for the GLib.VariantType of format to mismatch the type given in the schema.

      Parameters:
      key - the key to set the value for
      format - a GLib.Variant format string
      varargs - arguments as per format
      Returns:
      true if setting the key succeeded, false if the key was not writable
      Since:
      2.26

    • setBoolean

      public boolean setBoolean(String key, boolean value)

      Sets key in this Settings to value.

      A convenience variant of set(String, String, Object...) for booleans.

      It is a programmer error to give a key that isn’t specified as having a b type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to set the value for
      value - the value to set it to
      Returns:
      true if setting the key succeeded, false if the key was not writable
      Since:
      2.26

    • setDouble

      public boolean setDouble(String key, double value)

      Sets key in this Settings to value.

      A convenience variant of set(String, String, Object...) for doubles.

      It is a programmer error to give a key that isn’t specified as having a d type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to set the value for
      value - the value to set it to
      Returns:
      true if setting the key succeeded, false if the key was not writable
      Since:
      2.26

    • setEnum

      public boolean setEnum(String key, int value)

      Looks up the enumerated type nick for value and writes it to key, within settings.

      It is a programmer error to give a key that isn’t contained in the schema for this Settings or is not marked as an enumerated type, or for value not to be a valid value for the named type.

      After performing the write, accessing key directly with getString(String) will return the ‘nick’ associated with value.

      Parameters:
      key - the key to set the value for
      value - an enumerated value
      Returns:
      true if the set succeeds, false otherwise

    • setFlags

      public boolean setFlags(String key, int value)

      Looks up the flags type nicks for the bits specified by value, puts them in an array of strings and writes the array to key, within settings.

      It is a programmer error to give a key that isn’t contained in the schema for this Settings or is not marked as a flags type, or for value to contain any bits that are not value for the named type.

      After performing the write, accessing key directly with getStrv(String) will return an array of ‘nicks’; one for each bit in value.

      Parameters:
      key - the key to set the value for
      value - a flags value
      Returns:
      true if the set succeeds, false otherwise

    • setInt

      public boolean setInt(String key, int value)

      Sets key in this Settings to value.

      A convenience variant of set(String, String, Object...) for 32-bit integers.

      It is a programmer error to give a key that isn’t specified as having an i type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to set the value for
      value - the value to set it to
      Returns:
      true if setting the key succeeded, false if the key was not writable
      Since:
      2.26

    • setInt64

      public boolean setInt64(String key, long value)

      Sets key in this Settings to value.

      A convenience variant of set(String, String, Object...) for 64-bit integers.

      It is a programmer error to give a key that isn’t specified as having an x type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to set the value for
      value - the value to set it to
      Returns:
      true if setting the key succeeded, false if the key was not writable
      Since:
      2.50

    • setString

      public boolean setString(String key, String value)

      Sets key in this Settings to value.

      A convenience variant of set(String, String, Object...) for strings.

      It is a programmer error to give a key that isn’t specified as having an s type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to set the value for
      value - the value to set it to
      Returns:
      true if setting the key succeeded, false if the key was not writable
      Since:
      2.26

    • setStrv

      public boolean setStrv(String key, @Nullable String @Nullable [] value)

      Sets key in this Settings to value.

      A convenience variant of set(String, String, Object...) for string arrays. If value is NULL, then key is set to be the empty array.

      It is a programmer error to give a key that isn’t specified as having an as type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to set the value for
      value - the value to set it to
      Returns:
      true if setting the key succeeded, false if the key was not writable
      Since:
      2.26

    • setUint

      public boolean setUint(String key, int value)

      Sets key in this Settings to value.

      A convenience variant of set(String, String, Object...) for 32-bit unsigned integers.

      It is a programmer error to give a key that isn’t specified as having a u type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to set the value for
      value - the value to set it to
      Returns:
      true if setting the key succeeded, false if the key was not writable
      Since:
      2.30

    • setUint64

      public boolean setUint64(String key, long value)

      Sets key in this Settings to value.

      A convenience variant of set(String, String, Object...) for 64-bit unsigned integers.

      It is a programmer error to give a key that isn’t specified as having a t type in the schema for this Settings (see GLib.VariantType).

      Parameters:
      key - the key to set the value for
      value - the value to set it to
      Returns:
      true if setting the key succeeded, false if the key was not writable
      Since:
      2.50

    • setValue

      public boolean setValue(String key, Variant value)

      Sets key in this Settings to value.

      It is a programmer error to give a key that isn’t contained in the schema for this Settings or for value to have the incorrect type, per the schema.

      If value is floating then this function consumes the reference.

      Parameters:
      key - the key to set the value for
      value - a GLib.Variant of the correct type
      Returns:
      true if setting the key succeeded, false if the key was not writable
      Since:
      2.26

    • changeEvent

      protected boolean changeEvent(MemorySegment keys, int nKeys)

    • changed

      protected void changed(String key)

    • writableChangeEvent

      protected boolean writableChangeEvent(Quark key)

    • writableChanged

      protected void writableChanged(String key)

    • onChangeEvent

      public SignalConnection<Settings.ChangeEventCallback> onChangeEvent(Settings.ChangeEventCallback handler)

      Emitted once per change event that affects this settings object.

      You should connect to this signal only if you are interested in viewing groups of changes before they are split out into multiple emissions of the Gio.Settings::changed signal. For most use cases it is more appropriate to use the Gio.Settings::changed signal.

      In the event that the change event applies to one or more specified keys, keys will be an array of GLib.Quarks of length nKeys. In the event that the change event applies to the Settings object as a whole (ie: potentially every key has been changed) then keys will be NULL and nKeys will be 0.

      The default handler for this signal invokes the Gio.Settings::changed signal for each affected key. If any other connected handler returns true then this default functionality will be suppressed.

      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitChangeEvent

      public boolean emitChangeEvent(@Nullable Quark @Nullable [] keys)
      Emits the "change-event" signal. See onChangeEvent(Settings.ChangeEventCallback).

    • onChanged

      public SignalConnection<Settings.ChangedCallback> onChanged(@Nullable String detail, Settings.ChangedCallback handler)

      Emitted when a key has potentially changed.

      You should call one of the get(String, String, Object...) calls to check the new value.

      This signal supports detailed connections. You can connect to the detailed signal changed::x in order to only receive callbacks when key x changes.

      Note that settings only emits this signal if you have read key at least once while a signal handler was already connected for key.

      Parameters:
      detail - the signal detail
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitChanged

      public void emitChanged(@Nullable String detail, String key)
      Emits the "changed" signal. See onChanged(String, Settings.ChangedCallback).

    • onWritableChangeEvent

      public SignalConnection<Settings.WritableChangeEventCallback> onWritableChangeEvent(Settings.WritableChangeEventCallback handler)

      Emitted once per writability change event that affects this settings object.

      You should connect to this signal if you are interested in viewing groups of changes before they are split out into multiple emissions of the Gio.Settings::writable-changed signal. For most use cases it is more appropriate to use the Gio.Settings::writable-changed signal.

      In the event that the writability change applies only to a single key, key will be set to the GLib.Quark for that key. In the event that the writability change affects the entire settings object, key will be 0.

      The default handler for this signal invokes the Gio.Settings::writable-changed and Gio.Settings::changed signals for each affected key. This is done because changes in writability might also imply changes in value (if for example, a new mandatory setting is introduced). If any other connected handler returns true then this default functionality will be suppressed.

      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitWritableChangeEvent

      public boolean emitWritableChangeEvent(int key)
      Emits the "writable-change-event" signal. See onWritableChangeEvent(Settings.WritableChangeEventCallback).

    • onWritableChanged

      public SignalConnection<Settings.WritableChangedCallback> onWritableChanged(@Nullable String detail, Settings.WritableChangedCallback handler)

      Emitted when the writability of a key has potentially changed.

      You should call isWritable(String) in order to determine the new status.

      This signal supports detailed connections. You can connect to the detailed signal writable-changed::x in order to only receive callbacks when the writability of x changes.

      Parameters:
      detail - the signal detail
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitWritableChanged

      public void emitWritableChanged(@Nullable String detail, String key)
      Emits the "writable-changed" signal. See onWritableChanged(String, Settings.WritableChangedCallback).

    • builder

      public static Settings.Builder<? extends Settings.Builder> builder()
      A Settings.Builder object constructs a Settings with the specified properties. Use the various set...() methods to set properties, and finish construction with Settings.Builder.build().
      Returns:
      the builder object