QGIS API Documentation 3.37.0-Master (684a802617f)
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Public Types | Public Member Functions | Static Public Member Functions | List of all members
QgsSettings Class Reference

This class is a composition of two QSettings instances: More...

#include <qgssettings.h>

Inheritance diagram for QgsSettings:
Inheritance graph
[legend]

Public Types

enum  Section {
  NoSection , Core , Gui , Server ,
  Plugins , Auth , App , Providers ,
  Expressions , Misc , Gps
}
 Sections for namespaced settings. More...
 

Public Member Functions

 QgsSettings (const QString &fileName, QSettings::Format format, QObject *parent=nullptr)
 Constructs a QgsSettings object for accessing the settings stored in the file called fileName, with parent parent.
 
 QgsSettings (const QString &organization, const QString &application=QString(), QObject *parent=nullptr)
 Constructs a QgsSettings object for accessing settings of the application called application from the organization called organization, and with parent parent.
 
 QgsSettings (QObject *parent=nullptr)
 Constructs a QgsSettings object for accessing settings of the application and organization set previously with a call to QCoreApplication::setOrganizationName(), QCoreApplication::setOrganizationDomain(), and QCoreApplication::setApplicationName().
 
 QgsSettings (QSettings::Format format, QSettings::Scope scope, const QString &organization, const QString &application=QString(), QObject *parent=nullptr)
 Constructs a QgsSettings object for accessing settings of the application called application from the organization called organization, and with parent parent.
 
 QgsSettings (QSettings::Scope scope, const QString &organization, const QString &application=QString(), QObject *parent=nullptr)
 Constructs a QgsSettings object for accessing settings of the application called application from the organization called organization, and with parent parent.
 
 ~QgsSettings () override
 
QStringList allKeys () const
 Returns a list of all keys, including subkeys, that can be read using the QSettings object.
 
void beginGroup (const QString &prefix, QgsSettings::Section section=QgsSettings::NoSection)
 Appends prefix to the current group.
 
int beginReadArray (const QString &prefix)
 Adds prefix to the current group and starts reading from an array. Returns the size of the array.
 
void beginWriteArray (const QString &prefix, int size=-1)
 Adds prefix to the current group and starts writing an array of size size.
 
QStringList childGroups (Qgis::SettingsOrigin origin=Qgis::SettingsOrigin::Any) const
 Returns a list of all key top-level groups that contain keys that can be read using the QSettings object.
 
QStringList childKeys () const
 Returns a list of all top-level keys that can be read using the QSettings object.
 
void clear ()
 Removes all entries in the user settings.
 
bool contains (const QString &key, QgsSettings::Section section=QgsSettings::NoSection) const
 Returns true if there exists a setting called key; returns false otherwise.
 
void endArray ()
 Closes the array that was started using beginReadArray() or beginWriteArray().
 
void endGroup ()
 Resets the group to what it was before the corresponding beginGroup() call.
 
template<class T >
enumValue (const QString &key, const T &defaultValue, const Section section=NoSection)
 Returns the setting value for a setting based on an enum.
 
QString fileName () const
 Returns the path where settings written using this QSettings object are stored.
 
template<class T >
flagValue (const QString &key, const T &defaultValue, const Section section=NoSection)
 Returns the setting value for a setting based on a flag.
 
QStringList globalChildGroups () const
 Returns a list of all key top-level groups (same as childGroups) but only for groups defined in global settings.
 
QString group () const
 Returns the current group.
 
Qgis::SettingsOrigin origin (const QString &key) const
 Returns the origin of the setting if it exists at the given key.
 
QString prefixedKey (const QString &key, QgsSettings::Section section) const
 Returns the sanitized and prefixed key.
 
void remove (const QString &key, QgsSettings::Section section=QgsSettings::NoSection)
 Removes the setting key and any sub-settings of key in a section.
 
void setArrayIndex (int i)
 Sets the current array index to i.
 
template<class T >
void setEnumValue (const QString &key, const T &value, const Section section=NoSection)
 Set the value of a setting based on an enum.
 
template<class T >
void setFlagValue (const QString &key, const T &value, const Section section=NoSection)
 Set the value of a setting based on a flag.
 
void setValue (const QString &key, const QVariant &value, QgsSettings::Section section=QgsSettings::NoSection)
 Sets the value of setting key to value.
 
void sync ()
 Writes any unsaved changes to permanent storage, and reloads any settings that have been changed in the meantime by another application.
 
QVariant value (const QString &key, const QVariant &defaultValue=QVariant(), Section section=NoSection) const
 Returns the value for setting key.
 

Static Public Member Functions

static QgsSettingsProxy get ()
 Returns a proxy for a QgsSettings object.
 
static QString globalSettingsPath ()
 Returns the path to the Global Settings QSettings storage file.
 
static void holdFlush ()
 Temporarily places a hold on flushing QgsSettings objects and writing new values to the underlying ini files.
 
static void releaseFlush ()
 Releases a previously made hold on flushing QgsSettings objects and writing new values to the underlying ini files.
 
static bool setGlobalSettingsPath (const QString &path)
 Sets the Global Settings QSettings storage file.
 

Detailed Description

This class is a composition of two QSettings instances:

For a given settings key, the function call to value(key, default) will return the first existing setting in the order specified below:

The path to the Global Settings storage can be set before constructing the QgsSettings objects, with a static call to: static bool setGlobalSettingsPath( QString path );

QgsSettings provides some shortcuts to get/set namespaced settings from/to a specific section:

Definition at line 63 of file qgssettings.h.

Member Enumeration Documentation

◆ Section

Sections for namespaced settings.

Enumerator
NoSection 
Core 
Gui 
Server 
Plugins 
Auth 
App 
Providers 
Expressions 
Misc 
Gps 

GPS section, since QGIS 3.22.

Definition at line 69 of file qgssettings.h.

Constructor & Destructor Documentation

◆ QgsSettings() [1/5]

QgsSettings::QgsSettings ( const QString &  organization,
const QString &  application = QString(),
QObject *  parent = nullptr 
)
explicit

Constructs a QgsSettings object for accessing settings of the application called application from the organization called organization, and with parent parent.

Definition at line 53 of file qgssettings.cpp.

◆ QgsSettings() [2/5]

QgsSettings::QgsSettings ( QSettings::Scope  scope,
const QString &  organization,
const QString &  application = QString(),
QObject *  parent = nullptr 
)

Constructs a QgsSettings object for accessing settings of the application called application from the organization called organization, and with parent parent.

If scope is QSettings::UserScope, the QSettings object searches user-specific settings first, before it searches system-wide settings as a fallback. If scope is QSettings::SystemScope, the QSettings object ignores user-specific settings and provides access to system-wide settings.

The storage format is set to QSettings::NativeFormat (i.e. calling setDefaultFormat() before calling this constructor has no effect).

If no application name is given, the QSettings object will only access the organization-wide locations.

Definition at line 59 of file qgssettings.cpp.

◆ QgsSettings() [3/5]

QgsSettings::QgsSettings ( QSettings::Format  format,
QSettings::Scope  scope,
const QString &  organization,
const QString &  application = QString(),
QObject *  parent = nullptr 
)

Constructs a QgsSettings object for accessing settings of the application called application from the organization called organization, and with parent parent.

If scope is QSettings::UserScope, the QSettings object searches user-specific settings first, before it searches system-wide settings as a fallback. If scope is QSettings::SystemScope, the QSettings object ignores user-specific settings and provides access to system-wide settings.

If format is QSettings::NativeFormat, the native API is used for storing settings. If format is QSettings::IniFormat, the INI format is used.

If no application name is given, the QSettings object will only access the organization-wide locations.

Definition at line 66 of file qgssettings.cpp.

◆ QgsSettings() [4/5]

QgsSettings::QgsSettings ( const QString &  fileName,
QSettings::Format  format,
QObject *  parent = nullptr 
)

Constructs a QgsSettings object for accessing the settings stored in the file called fileName, with parent parent.

If the file doesn't already exist, it is created.

If format is QSettings::NativeFormat, the meaning of fileName depends on the platform. On Unix, fileName is the name of an INI file. On macOS and iOS, fileName is the name of a .plist file. On Windows, fileName is a path in the system registry.

If format is QSettings::IniFormat, fileName is the name of an INI file.

Warning
This function is provided for convenience. It works well for accessing INI or .plist files generated by Qt, but might fail on some syntaxes found in such files originated by other programs. In particular, be aware of the following limitations:
  • QgsSettings provides no way of reading INI "path" entries, i.e., entries with unescaped slash characters. (This is because these entries are ambiguous and cannot be resolved automatically.)
  • In INI files, QSettings uses the @ character as a metacharacter in some contexts, to encode Qt-specific data types (e.g., @Rect), and might therefore misinterpret it when it occurs in pure INI files.

Definition at line 73 of file qgssettings.cpp.

◆ QgsSettings() [5/5]

QgsSettings::QgsSettings ( QObject *  parent = nullptr)
explicit

Constructs a QgsSettings object for accessing settings of the application and organization set previously with a call to QCoreApplication::setOrganizationName(), QCoreApplication::setOrganizationDomain(), and QCoreApplication::setApplicationName().

The scope is QSettings::UserScope and the format is defaultFormat() (QSettings::NativeFormat by default). Use setDefaultFormat() before calling this constructor to change the default format used by this constructor.

Definition at line 79 of file qgssettings.cpp.

◆ ~QgsSettings()

QgsSettings::~QgsSettings ( )
override

Definition at line 85 of file qgssettings.cpp.

Member Function Documentation

◆ allKeys()

QStringList QgsSettings::allKeys ( ) const

Returns a list of all keys, including subkeys, that can be read using the QSettings object.

Definition at line 116 of file qgssettings.cpp.

◆ beginGroup()

void QgsSettings::beginGroup ( const QString &  prefix,
QgsSettings::Section  section = QgsSettings::NoSection 
)

Appends prefix to the current group.

The current group is automatically prepended to all keys specified to QSettings. In addition, query functions such as childGroups(), childKeys(), and allKeys() are based on the group. By default, no group is set.

Definition at line 92 of file qgssettings.cpp.

◆ beginReadArray()

int QgsSettings::beginReadArray ( const QString &  prefix)

Adds prefix to the current group and starts reading from an array. Returns the size of the array.

Definition at line 253 of file qgssettings.cpp.

◆ beginWriteArray()

void QgsSettings::beginWriteArray ( const QString &  prefix,
int  size = -1 
)

Adds prefix to the current group and starts writing an array of size size.

If size is -1 (the default), it is automatically determined based on the indexes of the entries written.

Note
This will completely shadow any existing array with the same name in the global settings

Definition at line 264 of file qgssettings.cpp.

◆ childGroups()

QStringList QgsSettings::childGroups ( Qgis::SettingsOrigin  origin = Qgis::SettingsOrigin::Any) const

Returns a list of all key top-level groups that contain keys that can be read using the QSettings object.

Definition at line 139 of file qgssettings.cpp.

◆ childKeys()

QStringList QgsSettings::childKeys ( ) const

Returns a list of all top-level keys that can be read using the QSettings object.

Definition at line 128 of file qgssettings.cpp.

◆ clear()

void QgsSettings::clear ( )

Removes all entries in the user settings.

Definition at line 332 of file qgssettings.cpp.

◆ contains()

bool QgsSettings::contains ( const QString &  key,
QgsSettings::Section  section = QgsSettings::NoSection 
) const

Returns true if there exists a setting called key; returns false otherwise.

If a group is set using beginGroup(), key is taken to be relative to that group.

Definition at line 188 of file qgssettings.cpp.

◆ endArray()

void QgsSettings::endArray ( )

Closes the array that was started using beginReadArray() or beginWriteArray().

Definition at line 270 of file qgssettings.cpp.

◆ endGroup()

void QgsSettings::endGroup ( )

Resets the group to what it was before the corresponding beginGroup() call.

Definition at line 102 of file qgssettings.cpp.

◆ enumValue()

template<class T >
T QgsSettings::enumValue ( const QString &  key,
const T &  defaultValue,
const Section  section = NoSection 
)
inline

Returns the setting value for a setting based on an enum.

This forces the output to be a valid and existing entry of the enum. Hence if the setting value is incorrect, the given default value is returned. This tries first with setting as a string (as the enum) and then as an integer value.

Note
The enum needs to be declared with Q_ENUM, and flags with Q_FLAG (not Q_FLAGS).
for Python bindings, a custom implementation is achieved in Python directly
See also
setEnumValue
flagValue

Definition at line 263 of file qgssettings.h.

◆ fileName()

QString QgsSettings::fileName ( ) const

Returns the path where settings written using this QSettings object are stored.

Definition at line 195 of file qgssettings.cpp.

◆ flagValue()

template<class T >
T QgsSettings::flagValue ( const QString &  key,
const T &  defaultValue,
const Section  section = NoSection 
)
inline

Returns the setting value for a setting based on a flag.

This forces the output to be a valid and existing entry of the flag. Hence if the setting value is incorrect, the given default value is returned. This tries first with setting as a string (using a byte array) and then as an integer value.

Note
The flag needs to be declared with Q_FLAG (not Q_FLAGS).
for Python bindings, a custom implementation is achieved in Python directly.
See also
setFlagValue
enumValue

Definition at line 341 of file qgssettings.h.

◆ get()

QgsSettingsProxy QgsSettings::get ( )
static

Returns a proxy for a QgsSettings object.

This either directly constructs a QgsSettings object, or if a previous call to holdFlush() has been made then the thread local QgsSettings object will be used.

Warning
ALWAYS use this function to retrieve a QgsSettings object for entries, NEVER create one manually!
Note
Not available in Python bindings
Since
QGIS 3.36

Definition at line 352 of file qgssettings.cpp.

◆ globalChildGroups()

QStringList QgsSettings::globalChildGroups ( ) const

Returns a list of all key top-level groups (same as childGroups) but only for groups defined in global settings.

Definition at line 164 of file qgssettings.cpp.

◆ globalSettingsPath()

QString QgsSettings::globalSettingsPath ( )
static

Returns the path to the Global Settings QSettings storage file.

Definition at line 169 of file qgssettings.cpp.

◆ group()

QString QgsSettings::group ( ) const

Returns the current group.

See also
beginGroup()
endGroup()
Since
QGIS 3.6

Definition at line 111 of file qgssettings.cpp.

◆ holdFlush()

void QgsSettings::holdFlush ( )
static

Temporarily places a hold on flushing QgsSettings objects and writing new values to the underlying ini files.

This can be used in code which access multiple settings to avoid creation and destruction of many QgsSettings objects for each in turn. This can be a VERY expensive operation due to flushing of new values to disk.

Warning
This method ONLY affects access to the settings from the current thread!
A corresponding call to releaseFlush() MUST be made from the SAME thread.
See also
releaseFlush()
Note
Not available in Python bindings
Since
QGIS 3.36

Definition at line 338 of file qgssettings.cpp.

◆ origin()

Qgis::SettingsOrigin QgsSettings::origin ( const QString &  key) const

Returns the origin of the setting if it exists at the given key.

Note
it will return Qgis::SettingsOrigin::Any if the key doesn't exist
Since
QGIS 3.30

Definition at line 292 of file qgssettings.cpp.

◆ prefixedKey()

QString QgsSettings::prefixedKey ( const QString &  key,
QgsSettings::Section  section 
) const

Returns the sanitized and prefixed key.

Definition at line 211 of file qgssettings.cpp.

◆ releaseFlush()

void QgsSettings::releaseFlush ( )
static

Releases a previously made hold on flushing QgsSettings objects and writing new values to the underlying ini files.

Warning
This method ONLY affects access to the settings from the current thread!
This must ALWAYS be called after a corresponding call to holdFlush() and MUST be made from the SAME thread.
See also
holdFlush()
Note
Not available in Python bindings
Since
QGIS 3.36

Definition at line 346 of file qgssettings.cpp.

◆ remove()

void QgsSettings::remove ( const QString &  key,
QgsSettings::Section  section = QgsSettings::NoSection 
)

Removes the setting key and any sub-settings of key in a section.

Definition at line 205 of file qgssettings.cpp.

◆ setArrayIndex()

void QgsSettings::setArrayIndex ( int  i)

Sets the current array index to i.

Calls to functions such as setValue(), value(), remove(), and contains() will operate on the array entry at that index.

Definition at line 280 of file qgssettings.cpp.

◆ setEnumValue()

template<class T >
void QgsSettings::setEnumValue ( const QString &  key,
const T &  value,
const Section  section = NoSection 
)
inline

Set the value of a setting based on an enum.

The setting will be saved as string.

Note
The enum needs to be declared with Q_ENUM, and flags with Q_FLAG (not Q_FLAGS).
See also
enumValue
setFlagValue

Definition at line 315 of file qgssettings.h.

◆ setFlagValue()

template<class T >
void QgsSettings::setFlagValue ( const QString &  key,
const T &  value,
const Section  section = NoSection 
)
inline

Set the value of a setting based on a flag.

The setting will be saved as string.

Note
The flag needs to be declared with Q_FLAG (not Q_FLAGS).
See also
flagValue
setEnumValue

Definition at line 405 of file qgssettings.h.

◆ setGlobalSettingsPath()

bool QgsSettings::setGlobalSettingsPath ( const QString &  path)
static

Sets the Global Settings QSettings storage file.

Definition at line 31 of file qgssettings.cpp.

◆ setValue()

void QgsSettings::setValue ( const QString &  key,
const QVariant &  value,
QgsSettings::Section  section = QgsSettings::NoSection 
)

Sets the value of setting key to value.

If the key already exists, the previous value is overwritten. An optional Section argument can be used to set a value to a specific Section.

Definition at line 303 of file qgssettings.cpp.

◆ sync()

void QgsSettings::sync ( )

Writes any unsaved changes to permanent storage, and reloads any settings that have been changed in the meantime by another application.

This function is called automatically from QSettings's destructor and by the event loop at regular intervals, so you normally don't need to call it yourself.

Definition at line 200 of file qgssettings.cpp.

◆ value()

QVariant QgsSettings::value ( const QString &  key,
const QVariant &  defaultValue = QVariant(),
const QgsSettings::Section  section = NoSection 
) const

Returns the value for setting key.

If the setting doesn't exist, it will be searched in the Global Settings and if not found, returns defaultValue. If no default value is specified, a default QVariant is returned. An optional Section argument can be used to get a value from a specific Section.

Definition at line 174 of file qgssettings.cpp.


The documentation for this class was generated from the following files: