QMetaEnum Class

The QMetaEnum class provides meta-data about an enumerator. More...

Header: #include <QMetaEnum>
qmake: QT += core

Public Functions

const char *enumName() const
bool isFlag() const
bool isScoped() const
bool isValid() const
const char *key(int index) const
int keyCount() const
int keyToValue(const char *key, bool *ok = nullptr) const
int keysToValue(const char *keys, bool *ok = nullptr) const
const char *name() const
const char *scope() const
int value(int index) const
const char *valueToKey(int value) const
QByteArray valueToKeys(int value) const

Static Public Members

QMetaEnum fromType()

Detailed Description

The QMetaEnum class provides meta-data about an enumerator.

Use name() for the enumerator's name. The enumerator's keys (names of each enumerated item) are returned by key(); use keyCount() to find the number of keys. isFlag() returns whether the enumerator is meant to be used as a flag, meaning that its values can be combined using the OR operator.

The conversion functions keyToValue(), valueToKey(), keysToValue(), and valueToKeys() allow conversion between the integer representation of an enumeration or set value and its literal representation. The scope() function returns the class scope this enumerator was declared in.

See also QMetaObject, QMetaMethod, and QMetaProperty.

Member Function Documentation

const char *QMetaEnum::enumName() const

Returns the enum name of the flag (without the scope).

For example, the Qt::AlignmentFlag flag has AlignmentFlag as the enum name, but Alignment as as the type name. Non flag enums has the same type and enum names.

Enum names have the same scope as the type name.

This function was introduced in Qt 5.12.

See also isValid() and name().

[static] QMetaEnum QMetaEnum::fromType()

Returns the QMetaEnum corresponding to the type in the template parameter. The enum needs to be declared with Q_ENUM.

This function was introduced in Qt 5.5.

bool QMetaEnum::isFlag() const

Returns true if this enumerator is used as a flag; otherwise returns false.

When used as flags, enumerators can be combined using the OR operator.

See also keysToValue() and valueToKeys().

bool QMetaEnum::isScoped() const

Returns true if this enumerator is declared as a C++11 enum class; otherwise returns false.

This function was introduced in Qt 5.8.

bool QMetaEnum::isValid() const

Returns true if this enum is valid (has a name); otherwise returns false.

See also name().

const char *QMetaEnum::key(int index) const

Returns the key with the given index, or 0 if no such key exists.

See also keyCount(), value(), and valueToKey().

int QMetaEnum::keyCount() const

Returns the number of keys.

See also key().

int QMetaEnum::keyToValue(const char *key, bool *ok = nullptr) const

Returns the integer value of the given enumeration key, or -1 if key is not defined.

If key is not defined, *ok is set to false; otherwise *ok is set to true.

For flag types, use keysToValue().

See also valueToKey(), isFlag(), and keysToValue().

int QMetaEnum::keysToValue(const char *keys, bool *ok = nullptr) const

Returns the value derived from combining together the values of the keys using the OR operator, or -1 if keys is not defined. Note that the strings in keys must be '|'-separated.

If keys is not defined, *ok is set to false; otherwise *ok is set to true.

See also isFlag(), valueToKey(), and valueToKeys().

const char *QMetaEnum::name() const

Returns the name of the type (without the scope).

For example, the Qt::Key enumeration has Key as the type name and Qt as the scope.

For flags this returns the name of the flag type, not the name of the enum type.

See also isValid(), scope(), and enumName().

const char *QMetaEnum::scope() const

Returns the scope this enumerator was declared in.

For example, the Qt::AlignmentFlag enumeration has Qt as the scope and AlignmentFlag as the name.

See also name().

int QMetaEnum::value(int index) const

Returns the value with the given index; or returns -1 if there is no such value.

See also keyCount(), key(), and keyToValue().

const char *QMetaEnum::valueToKey(int value) const

Returns the string that is used as the name of the given enumeration value, or 0 if value is not defined.

For flag types, use valueToKeys().

See also isFlag() and valueToKeys().

QByteArray QMetaEnum::valueToKeys(int value) const

Returns a byte array of '|'-separated keys that represents the given value.

See also isFlag(), valueToKey(), and keysToValue().

© 2018 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.