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QJsonDocument Class Reference

\inmodule QtCore\reentrant More...

#include <qjsondocument.h>

Collaboration diagram for QJsonDocument:

Public Types

using JsonFormat = QJsonValue::JsonFormat

Public Member Functions

 QJsonDocument ()
 Constructs an empty and invalid document.
 QJsonDocument (const QJsonObject &object)
 Creates a QJsonDocument from object.
 QJsonDocument (QJsonObject &&object)
 QJsonDocument (const QJsonArray &array)
 Constructs a QJsonDocument from array.
 QJsonDocument (QJsonArray &&array)
 ~QJsonDocument ()
 Deletes the document.
 QJsonDocument (const QJsonDocument &other)
 Creates a copy of the other document.
QJsonDocument & operator= (const QJsonDocument &other)
 Assigns the other document to this QJsonDocument.
 QJsonDocument (QJsonDocument &&other) noexcept
void swap (QJsonDocument &other) noexcept
QVariant toVariant () const
 Returns a QVariant representing the Json document.
QByteArray toJson (JsonFormat format=JsonFormat::Indented) const
 \typealias QJsonDocument::JsonFormat
bool isEmpty () const
 Returns true if the document doesn't contain any data.
bool isArray () const
 Returns true if the document contains an array.
bool isObject () const
 Returns true if the document contains an object.
QJsonObject object () const
 Returns the QJsonObject contained in the document.
QJsonArray array () const
 Returns the QJsonArray contained in the document.
void setObject (const QJsonObject &object)
 Sets object as the main object of this document.
void setArray (const QJsonArray &array)
 Sets array as the main object of this document.
const QJsonValue operator[] (const QString &key) const
 Returns a QJsonValue representing the value for the key key.
const QJsonValue operator[] (QStringView key) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
const QJsonValue operator[] (QLatin1StringView key) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
const QJsonValue operator[] (qsizetype i) const
 Returns a QJsonValue representing the value for index i.
bool isNull () const
 returns true if this document is null.

Static Public Member Functions

static QJsonDocument fromVariant (const QVariant &variant)
 Creates a QJsonDocument from the QVariant variant.
static QJsonDocument fromJson (const QByteArray &json, QJsonParseError *error=nullptr)
 Parses json as a UTF-8 encoded JSON document, and creates a QJsonDocument from it.

Static Public Attributes

static const uint BinaryFormatTag = ('q' << 24) | ('b' << 16) | ('j' << 8) | ('s')
static constexpr auto Indented = JsonFormat::Indented
static constexpr auto Compact = JsonFormat::Compact

Friends

class QJsonValue
class QJsonPrivate::Parser
Q_CORE_EXPORT QDebug operator<< (QDebug dbg, const QJsonDocument &o)
Q_CORE_EXPORT bool comparesEqual (const QJsonDocument &lhs, const QJsonDocument &rhs)

Detailed Description

\inmodule QtCore

\reentrant

Since
5.0

The QJsonDocument class provides a way to read and write JSON documents.

\compares equality

QJsonDocument is a class that wraps a complete JSON document and can read this document from, and write it to, a UTF-8 encoded text-based representation.

A JSON document can be converted from its text-based representation to a QJsonDocument using QJsonDocument::fromJson(). toJson() converts it back to text. The parser is very fast and efficient and converts the JSON to the binary representation used by Qt.

Validity of the parsed document can be queried with !isNull()

A document can be queried as to whether it contains an array or an object using isArray() and isObject(). The array or object contained in the document can be retrieved using array() or object() and then read or manipulated.

See also
{JSON Support in Qt}, {Saving and Loading a Game}

Definition at line 28 of file qjsondocument.h.

Member Typedef Documentation

◆ JsonFormat

using QJsonDocument::JsonFormat = QJsonValue::JsonFormat

Definition at line 63 of file qjsondocument.h.

Constructor & Destructor Documentation

◆ QJsonDocument() [1/7]

QJsonDocument::QJsonDocument ( )

Constructs an empty and invalid document.

Definition at line 65 of file qjsondocument.cpp.

◆ QJsonDocument() [2/7]

QJsonDocument::QJsonDocument ( const QJsonObject & object)
explicit

Creates a QJsonDocument from object.

Definition at line 73 of file qjsondocument.cpp.

◆ QJsonDocument() [3/7]

QJsonDocument::QJsonDocument ( QJsonObject && object)
explicit
Since
6.12 Creates a QJsonDocument from object.

Definition at line 82 of file qjsondocument.cpp.

◆ QJsonDocument() [4/7]

QJsonDocument::QJsonDocument ( const QJsonArray & array)
explicit

Constructs a QJsonDocument from array.

Definition at line 91 of file qjsondocument.cpp.

◆ QJsonDocument() [5/7]

QJsonDocument::QJsonDocument ( QJsonArray && array)
explicit
Since
6.12 Constructs a QJsonDocument from array.

Definition at line 100 of file qjsondocument.cpp.

◆ ~QJsonDocument()

QJsonDocument::~QJsonDocument ( )

Deletes the document.

Binary data set with fromRawData is not freed.

Definition at line 120 of file qjsondocument.cpp.

◆ QJsonDocument() [6/7]

QJsonDocument::QJsonDocument ( const QJsonDocument & other)

Creates a copy of the other document.

Definition at line 128 of file qjsondocument.cpp.

◆ QJsonDocument() [7/7]

QJsonDocument::QJsonDocument ( QJsonDocument && other)
noexcept
Since
5.10

Move-constructs a QJsonDocument from other.

Member Function Documentation

◆ array()

QJsonArray QJsonDocument::array ( ) const

Returns the QJsonArray contained in the document.

Returns an empty array if the document contains an object.

See also
isArray(), object(), setArray()

Definition at line 351 of file qjsondocument.cpp.

◆ fromJson()

QJsonDocument QJsonDocument::fromJson ( const QByteArray & json,
QJsonParseError * error = nullptr )
static

Parses json as a UTF-8 encoded JSON document, and creates a QJsonDocument from it.

Returns a valid (non-null) QJsonDocument if the parsing succeeds. If it fails, the returned document will be null, and the optional error variable will contain further details about the error.

See also
toJson(), QJsonParseError, isNull()

Definition at line 273 of file qjsondocument.cpp.

◆ fromVariant()

QJsonDocument QJsonDocument::fromVariant ( const QVariant & variant)
static

Creates a QJsonDocument from the QVariant variant.

If the variant contains any other type than a QVariantMap, QVariantHash, QVariantList or QStringList, the returned document is invalid.

See also
toVariant()

Definition at line 182 of file qjsondocument.cpp.

◆ isArray()

bool QJsonDocument::isArray ( ) const

Returns true if the document contains an array.

See also
array(), isObject()

Definition at line 305 of file qjsondocument.cpp.

◆ isEmpty()

bool QJsonDocument::isEmpty ( ) const

Returns true if the document doesn't contain any data.

Definition at line 292 of file qjsondocument.cpp.

◆ isNull()

bool QJsonDocument::isNull ( ) const

returns true if this document is null.

Null documents are documents created through the default constructor.

Documents created from UTF-8 encoded text or the binary format are validated during parsing. If validation fails, the returned document will also be null.

Definition at line 468 of file qjsondocument.cpp.

◆ isObject()

bool QJsonDocument::isObject ( ) const

Returns true if the document contains an object.

See also
object(), isArray()

Definition at line 318 of file qjsondocument.cpp.

◆ object()

QJsonObject QJsonDocument::object ( ) const

Returns the QJsonObject contained in the document.

Returns an empty object if the document contains an array.

See also
isObject(), array(), setObject()

Definition at line 334 of file qjsondocument.cpp.

◆ operator=()

QJsonDocument & QJsonDocument::operator= ( const QJsonDocument & other)

Assigns the other document to this QJsonDocument.

Returns a reference to this object.

Since
5.10

Move-assigns other to this document.

Definition at line 137 of file qjsondocument.cpp.

◆ operator[]() [1/4]

const QJsonValue QJsonDocument::operator[] ( const QString & key) const

Returns a QJsonValue representing the value for the key key.

Equivalent to calling object().value(key).

The returned QJsonValue is QJsonValue::Undefined if the key does not exist, or if isObject() is false.

Since
5.10
See also
QJsonValue, QJsonValue::isUndefined(), QJsonObject

Definition at line 392 of file qjsondocument.cpp.

◆ operator[]() [2/4]

const QJsonValue QJsonDocument::operator[] ( QLatin1StringView key) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since
5.10

Definition at line 413 of file qjsondocument.cpp.

◆ operator[]() [3/4]

const QJsonValue QJsonDocument::operator[] ( qsizetype i) const

Returns a QJsonValue representing the value for index i.

Equivalent to calling array().at(i).

The returned QJsonValue is QJsonValue::Undefined, if i is out of bounds, or if isArray() is false.

Since
5.10
See also
QJsonValue, QJsonValue::isUndefined(), QJsonArray

Definition at line 433 of file qjsondocument.cpp.

◆ operator[]() [4/4]

const QJsonValue QJsonDocument::operator[] ( QStringView key) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since
5.14

Definition at line 401 of file qjsondocument.cpp.

◆ setArray()

void QJsonDocument::setArray ( const QJsonArray & array)

Sets array as the main object of this document.

See also
setObject(), array()

Definition at line 375 of file qjsondocument.cpp.

◆ setObject()

void QJsonDocument::setObject ( const QJsonObject & object)

Sets object as the main object of this document.

See also
setArray(), object()

Definition at line 365 of file qjsondocument.cpp.

◆ swap()

void QJsonDocument::swap ( QJsonDocument & other)
noexcept
Since
5.10 \memberswap{document}

◆ toJson()

QByteArray QJsonDocument::toJson ( JsonFormat format = JsonFormat::Indented) const

\typealias QJsonDocument::JsonFormat

Since
5.1

Same as \l QJsonValue::JsonFormat.

Since
5.1 Converts the QJsonDocument to a UTF-8 encoded JSON document in the provided format.
See also
fromJson(), JsonFormat

Definition at line 252 of file qjsondocument.cpp.

◆ toVariant()

QVariant QJsonDocument::toVariant ( ) const

Returns a QVariant representing the Json document.

The returned variant will be a QVariantList if the document is a QJsonArray and a QVariantMap if the document is a QJsonObject.

See also
fromVariant(), QJsonValue::toVariant()

Definition at line 213 of file qjsondocument.cpp.

◆ comparesEqual

Q_CORE_EXPORT bool comparesEqual ( const QJsonDocument & lhs,
const QJsonDocument & rhs )
friend

Definition at line 446 of file qjsondocument.cpp.

◆ operator<<

Q_CORE_EXPORT QDebug operator<< ( QDebug dbg,
const QJsonDocument & o )
friend

Definition at line 474 of file qjsondocument.cpp.

◆ QJsonPrivate::Parser

friend class QJsonPrivate::Parser
friend

Definition at line 99 of file qjsondocument.h.

◆ QJsonValue

friend class QJsonValue
friend

Definition at line 98 of file qjsondocument.h.

Member Data Documentation

◆ BinaryFormatTag

const uint QJsonDocument::BinaryFormatTag = ('q' << 24) | ('b' << 16) | ('j' << 8) | ('s')
static

Definition at line 34 of file qjsondocument.h.

◆ Compact

auto QJsonDocument::Compact = JsonFormat::Compact
staticconstexpr

Definition at line 69 of file qjsondocument.h.

◆ Indented

auto QJsonDocument::Indented = JsonFormat::Indented
staticconstexpr

Definition at line 68 of file qjsondocument.h.

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