QJsonObject 类

QJsonObject 类封装 JSON 对象。 更多...

头：	#include <QJsonObject>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Core) target_link_libraries(mytarget PRIVATE Qt6::Core)
qmake:	QT += core

• 所有成员列表，包括继承成员
• QJsonObject is part of 在 Qt 中支持 JSON and 隐式共享类 .

此类 相等可比较 .

此类 相等可比较 with QJsonValue and QJsonValueConstRef.

注意： 此类的所有函数 可重入 .

公共类型

class	const_iterator
class	iterator
	ConstIterator
	Iterator
(从 6.10 起)	const_key_value_iterator
	key_type
(从 6.10 起)	key_value_iterator
	mapped_type
	size_type

公共函数

	QJsonObject ()
	QJsonObject (std::initializer_list<std::pair<QString, QJsonValue>> args )
	QJsonObject (const QJsonObject & other )
	QJsonObject (QJsonObject && other )
	~QJsonObject ()
(从 6.10 起) auto	asKeyValueRange () &&
(从 6.10 起) auto	asKeyValueRange () &
(从 6.10 起) auto	asKeyValueRange () const &&
(从 6.10 起) auto	asKeyValueRange () const &
QJsonObject::iterator	begin ()
QJsonObject::const_iterator	begin () const
QJsonObject::const_iterator	constBegin () const
QJsonObject::const_iterator	constEnd () const
QJsonObject::const_iterator	constFind (const QString & key ) const
QJsonObject::const_iterator	constFind (QLatin1StringView key ) const
QJsonObject::const_iterator	constFind (QStringView key ) const
(从 6.10 起) QJsonObject::const_key_value_iterator	constKeyValueBegin () const
(从 6.10 起) QJsonObject::const_key_value_iterator	constKeyValueEnd () const
bool	contains (const QString & key ) const
bool	contains (QLatin1StringView key ) const
bool	contains (QStringView key ) const
qsizetype	count () const
bool	empty () const
QJsonObject::iterator	end ()
QJsonObject::const_iterator	end () const
QJsonObject::iterator	erase (QJsonObject::iterator it )
QJsonObject::iterator	find (const QString & key )
QJsonObject::iterator	find (QLatin1StringView key )
QJsonObject::iterator	find (QStringView key )
QJsonObject::const_iterator	find (QLatin1StringView key ) const
QJsonObject::const_iterator	find (QStringView key ) const
QJsonObject::const_iterator	find (const QString & key ) const
QJsonObject::iterator	insert (const QString & key , const QJsonValue & value )
QJsonObject::iterator	insert (QLatin1StringView key , const QJsonValue & value )
QJsonObject::iterator	insert (QStringView key , const QJsonValue & value )
bool	isEmpty () const
(从 6.10 起) QJsonObject::key_value_iterator	keyValueBegin ()
(从 6.10 起) QJsonObject::const_key_value_iterator	keyValueBegin () const
(从 6.10 起) QJsonObject::key_value_iterator	keyValueEnd ()
(从 6.10 起) QJsonObject::const_key_value_iterator	keyValueEnd () const
QStringList	keys () const
qsizetype	length () const
void	remove (const QString & key )
void	remove (QLatin1StringView key )
void	remove (QStringView key )
qsizetype	size () const
void	swap (QJsonObject & other )
QJsonValue	take (const QString & key )
QJsonValue	take (QLatin1StringView key )
QJsonValue	take (QStringView key )
QVariantHash	toVariantHash () const
QVariantMap	toVariantMap () const
QJsonValue	value (const QString & key ) const
QJsonValue	value (QLatin1StringView key ) const
QJsonValue	value (QStringView key ) const
QJsonObject &	operator= (QJsonObject && other )
QJsonObject &	operator= (const QJsonObject & other )
QJsonValueRef	operator[] (const QString & key )
QJsonValue	operator[] (const QString & key ) const
QJsonValueRef	operator[] (QLatin1StringView key )
QJsonValueRef	operator[] (QStringView key )
QJsonValue	operator[] (QLatin1StringView key ) const
QJsonValue	operator[] (QStringView key ) const

静态公共成员

QJsonObject	fromVariantHash (const QVariantHash & hash )
QJsonObject	fromVariantMap (const QVariantMap & map )

相关非成员

bool	operator!= (const QJsonObject & lhs , const QJsonObject & rhs )
bool	operator== (const QJsonObject & lhs , const QJsonObject & rhs )

详细描述

A JSON object is a list of key value pairs, where the keys are unique strings and the values are represented by a QJsonValue .

A QJsonObject can be converted to and from a QVariantMap . You can query the number of (key, value) pairs with size (), insert ()，和 remove () entries from it and iterate over its content using the standard C++ iterator pattern.

QJsonObject is an implicitly shared class, and shares the data with the document it has been created from as long as it is not being modified.

You can convert the object to and from text based JSON through QJsonDocument .

另请参阅 在 Qt 中支持 JSON and 保存和加载游戏 .

成员类型文档编制

QJsonObject:: ConstIterator

Qt 样式同义词 QJsonObject::const_iterator .

QJsonObject:: Iterator

Qt 样式同义词 QJsonObject::iterator .

[since 6.10] QJsonObject:: const_key_value_iterator

The QJsonObject::const_key_value_iterator typedef provides an STL-style iterator for QJsonObject .

QJsonObject::const_key_value_iterator is essentially the same as QJsonObject::const_iterator with the difference that operator*() returns a key/value pair instead of a value.

This typedef was introduced in Qt 6.10.

另请参阅 QKeyValueIterator .

QJsonObject:: key_type

typedef 对于 QString . Provided for STL compatibility.

[since 6.10] QJsonObject:: key_value_iterator

The QJsonObject::key_value_iterator typedef provides an STL-style iterator for QJsonObject .

QJsonObject::key_value_iterator is essentially the same as QJsonObject::iterator with the difference that operator*() returns a key/value pair instead of a value.

This typedef was introduced in Qt 6.10.

另请参阅 QKeyValueIterator .

QJsonObject:: mapped_type

typedef 对于 QJsonValue . Provided for STL compatibility.

QJsonObject:: size_type

Typedef for qsizetype. Provided for STL compatibility.

成员函数文档编制

[since 6.10] auto QJsonObject:: asKeyValueRange () &

[since 6.10] auto QJsonObject:: asKeyValueRange () &&

[since 6.10] auto QJsonObject:: asKeyValueRange () const &&

[since 6.10] auto QJsonObject:: asKeyValueRange () const &

Returns a range object that allows iteration over this object as key/value pairs. For instance, this range object can be used in a range-based for loop, in combination with a structured binding declaration:

QJsonObject obj{
    { "something", "is" },
    { "in", "this" },
    { "object", 42 },
};
for (auto [key, value] : obj.asKeyValueRange()) {
    qDebug() << key << "->" << value;
    if (key == "object")
        value = "!"; // modify the object at this key
}
qDebug() << obj["object"]; // QJsonValue(string, "!")
					

Note that the value obtained this way is a reference into the one in the object. Specifically, mutating the value will modify the object itself.

When calling this method on rvalues (e.g. on a temporary created in the inializer of a ranged for-loop), the object will be captured in this range.

These functions were introduced in Qt 6.10.

另请参阅 QKeyValueIterator .

QJsonObject:: QJsonObject ()

构造空的 JSON 对象。

另请参阅 isEmpty ().

QJsonObject:: QJsonObject ( std::initializer_list < std::pair < QString , QJsonValue >> args )

Constructs a QJsonObject instance initialized from args initialization list. For example:

QJsonObject object
{
    {"property1", 1},
    {"property2", 2}
};
					

[noexcept] QJsonObject:: QJsonObject (const QJsonObject & other )

创建副本为 other .

Since QJsonObject is implicitly shared, the copy is shallow as long as the object does not get modified.

[noexcept] QJsonObject:: QJsonObject ( QJsonObject && other )

移动构造 QJsonObject，从 other .

[noexcept] QJsonObject:: ~QJsonObject ()

销毁对象。

QJsonObject::iterator QJsonObject:: begin ()

返回 STL 样式迭代器 pointing to the first item in the object.

另请参阅 constBegin () 和 end ().

QJsonObject::const_iterator QJsonObject:: begin () const

这是重载函数。

QJsonObject::const_iterator QJsonObject:: constBegin () const

返回常量 STL 样式迭代器 pointing to the first item in the object.

另请参阅 begin () 和 constEnd ().

QJsonObject::const_iterator QJsonObject:: constEnd () const

返回常量 STL 样式迭代器 pointing to the imaginary item after the last item in the object.

另请参阅 constBegin () 和 end ().

QJsonObject::const_iterator QJsonObject:: constFind (const QString & key ) const

Returns a const iterator pointing to the item with key key in the map.

If the map contains no item with key key ，函数返回 constEnd ().

QJsonObject::const_iterator QJsonObject:: constFind ( QLatin1StringView key ) const

这是重载函数。

QJsonObject::const_iterator QJsonObject:: constFind ( QStringView key ) const

这是重载函数。

[since 6.10] QJsonObject::const_key_value_iterator QJsonObject:: constKeyValueBegin () const

返回常量 STL 样式迭代器 pointing to the first entry in the object.

该函数在 Qt 6.10 引入。

另请参阅 keyValueBegin ().

[since 6.10] QJsonObject::const_key_value_iterator QJsonObject:: constKeyValueEnd () const

返回常量 STL 样式迭代器 pointing to the imaginary entry after the last entry in the ibject.

该函数在 Qt 6.10 引入。

另请参阅 constKeyValueBegin ().

bool QJsonObject:: contains (const QString & key ) const

返回 true if the object contains key key .

另请参阅 insert (), remove ()，和 take ().

bool QJsonObject:: contains ( QLatin1StringView key ) const

这是重载函数。

bool QJsonObject:: contains ( QStringView key ) const

这是重载函数。

qsizetype QJsonObject:: count () const

如同 size ().

bool QJsonObject:: empty () const

此函数为兼容 STL (标准模板库) 提供。它相当于 isEmpty (), returning true if the object is empty; otherwise returning false .

QJsonObject::iterator QJsonObject:: end ()

返回 STL 样式迭代器 pointing to the imaginary item after the last item in the object.

另请参阅 begin () 和 constEnd ().

QJsonObject::const_iterator QJsonObject:: end () const

这是重载函数。

QJsonObject::iterator QJsonObject:: erase ( QJsonObject::iterator it )

Removes the (key, value) pair pointed to by the iterator it from the map, and returns an iterator to the next item in the map.

另请参阅 remove ().

QJsonObject::iterator QJsonObject:: find (const QString & key )

Returns an iterator pointing to the item with key key in the map.

If the map contains no item with key key ，函数返回 end ().

QJsonObject::iterator QJsonObject:: find ( QLatin1StringView key )

这是重载函数。

QJsonObject::iterator QJsonObject:: find ( QStringView key )

这是重载函数。

QJsonObject::const_iterator QJsonObject:: find ( QLatin1StringView key ) const

这是重载函数。

QJsonObject::const_iterator QJsonObject:: find ( QStringView key ) const

这是重载函数。

QJsonObject::const_iterator QJsonObject:: find (const QString & key ) const

这是重载函数。

[static] QJsonObject QJsonObject:: fromVariantHash (const QVariantHash & hash )

Converts the variant hash hash 到 QJsonObject .

The keys in hash will be used as the keys in the JSON object, and the QVariant values will be converted to JSON values.

注意： Conversion from QVariant is not completely lossless. Please see the documentation in QJsonValue::fromVariant () 了解更多信息。

另请参阅 fromVariantMap (), toVariantHash ()，和 QJsonValue::fromVariant ().

[static] QJsonObject QJsonObject:: fromVariantMap (const QVariantMap & map )

Converts the variant map map 到 QJsonObject .

The keys in map will be used as the keys in the JSON object, and the QVariant values will be converted to JSON values.

注意： Conversion from QVariant is not completely lossless. Please see the documentation in QJsonValue::fromVariant () 了解更多信息。

另请参阅 fromVariantHash (), toVariantMap ()，和 QJsonValue::fromVariant ().

QJsonObject::iterator QJsonObject:: insert (const QString & key , const QJsonValue & value )

Inserts a new item with the key key 和值 value .

If there is already an item with the key key , then that item's value is replaced with value .

Returns an iterator pointing to the inserted item.

If the value is QJsonValue::Undefined , it will cause the key to get removed from the object. The returned iterator will then point to end ().

另请参阅 remove (), take (), QJsonObject::iterator ，和 end ().

QJsonObject::iterator QJsonObject:: insert ( QLatin1StringView key , const QJsonValue & value )

这是重载函数。

QJsonObject::iterator QJsonObject:: insert ( QStringView key , const QJsonValue & value )

这是重载函数。

bool QJsonObject:: isEmpty () const

返回 true if the object is empty. This is the same as size () == 0.

另请参阅 size ().

[since 6.10] QJsonObject::key_value_iterator QJsonObject:: keyValueBegin ()

返回 STL 样式迭代器 pointing to the first entry in the object.

该函数在 Qt 6.10 引入。

另请参阅 keyValueEnd ().

[since 6.10] QJsonObject::const_key_value_iterator QJsonObject:: keyValueBegin () const

返回常量 STL 样式迭代器 pointing to the first entry in the object.

该函数在 Qt 6.10 引入。

另请参阅 keyValueEnd ().

[since 6.10] QJsonObject::key_value_iterator QJsonObject:: keyValueEnd ()

返回 STL 样式迭代器 pointing to the imaginary entry after the last entry in the object.

该函数在 Qt 6.10 引入。

另请参阅 keyValueBegin ().

[since 6.10] QJsonObject::const_key_value_iterator QJsonObject:: keyValueEnd () const

返回常量 STL 样式迭代器 pointing to the imaginary entry after the last entry in the object.

该函数在 Qt 6.10 引入。

另请参阅 keyValueBegin ().

QStringList QJsonObject:: keys () const

返回在此对象中的所有键列表。

The list is sorted alphabetically.

qsizetype QJsonObject:: length () const

如同 size ().

void QJsonObject:: remove (const QString & key )

移除 key 从对象。

另请参阅 insert () 和 take ().

void QJsonObject:: remove ( QLatin1StringView key )

这是重载函数。

void QJsonObject:: remove ( QStringView key )

这是重载函数。

qsizetype QJsonObject:: size () const

Returns the number of (key, value) pairs stored in the object.

[noexcept] void QJsonObject:: swap ( QJsonObject & other )

Swaps this object with other 。此操作很快且从不失败。

QJsonValue QJsonObject:: take (const QString & key )

移除 key 从对象。

返回 QJsonValue containing the value referenced by key 。若 key was not contained in the object, the returned QJsonValue is QJsonValue::Undefined .

另请参阅 insert (), remove ()，和 QJsonValue .

QJsonValue QJsonObject:: take ( QLatin1StringView key )

这是重载函数。

QJsonValue QJsonObject:: take ( QStringView key )

这是重载函数。

QVariantHash QJsonObject:: toVariantHash () const

把此对象转换成 QVariantHash .

返回创建的哈希。

另请参阅 toVariantMap ().

QVariantMap QJsonObject:: toVariantMap () const

把此对象转换成 QVariantMap .

返回创建的映射。

另请参阅 toVariantHash ().

QJsonValue QJsonObject:: value (const QString & key ) const

返回 QJsonValue 表示值为键 key .

返回的 QJsonValue is QJsonValue::Undefined 若键不存在。

另请参阅 QJsonValue and QJsonValue::isUndefined ().

QJsonValue QJsonObject:: value ( QLatin1StringView key ) const

这是重载函数。

QJsonValue QJsonObject:: value ( QStringView key ) const

这是重载函数。

[noexcept] QJsonObject &QJsonObject:: operator= ( QJsonObject && other )

移动赋值 other 到此对象。

[noexcept] QJsonObject &QJsonObject:: operator= (const QJsonObject & other )

赋值 other 到此对象。

QJsonValueRef QJsonObject:: operator[] (const QString & key )

Returns a reference to the value for key . If there is no value with key key in the object, one is created with a QJsonValue::Null value and then returned.

The return value is of type QJsonValueRef , a helper class for QJsonArray and QJsonObject . When you get an object of type QJsonValueRef , you can use it as if it were a reference to a QJsonValue . If you assign to it, the assignment will apply to the element in the QJsonArray or QJsonObject from which you got the reference.

另请参阅 value ().

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

返回 QJsonValue 表示值为键 key .

This does the same as value ().

返回的 QJsonValue is QJsonValue::Undefined 若键不存在。

另请参阅 value (), QJsonValue ，和 QJsonValue::isUndefined ().

QJsonValueRef QJsonObject:: operator[] ( QLatin1StringView key )

这是重载函数。

QJsonValueRef QJsonObject:: operator[] ( QStringView key )

这是重载函数。

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

这是重载函数。

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

这是重载函数。

相关非成员

[noexcept] bool operator!= (const QJsonObject & lhs , const QJsonObject & rhs )

返回 true if lhs object is not equal to rhs , false 否则。

[noexcept] bool operator== (const QJsonObject & lhs , const QJsonObject & rhs )

返回 true if lhs 对象等于 rhs , false 否则。

内容

1. 公共类型

2. 公共函数

3. 静态公共成员

4. 相关非成员

5. 详细描述