The QJsonObject::const_iterator 类提供 STL 样式 const 迭代器为 QJsonObject . 更多...
| 头： | #include <const_iterator> |
| qmake: | QT += core |
| Since: | Qt 5.0 |
| typedef | iterator_category |
| const_iterator () | |
| const_iterator (const iterator & other ) | |
| QString | key () const |
| QJsonValue | value () const |
| bool | operator!= (const const_iterator & other ) const |
| bool | operator!= (const iterator & other ) const |
| QJsonValue | operator* () const |
| const_iterator | operator+ (int j ) const |
| const_iterator & | operator++ () |
| const_iterator | operator++ ( int ) |
| const_iterator & | operator+= (int j ) |
| const_iterator | operator- (int j ) const |
| const_iterator & | operator-- () |
| const_iterator | operator-- ( int ) |
| const_iterator & | operator-= (int j ) |
| QJsonValue * | operator-> () const |
| bool | operator== (const const_iterator & other ) const |
| bool | operator== (const iterator & other ) const |
The QJsonObject::const_iterator 类提供 STL 样式 const 迭代器为 QJsonObject .
QJsonObject::const_iterator allows you to iterate over a QJsonObject . If you want to modify the QJsonObject as you iterate over it, you must use QJsonObject::iterator instead. It is generally good practice to use QJsonObject::const_iterator on a non-const QJsonObject as well, unless you need to change the QJsonObject through the iterator. Const iterators are slightly faster and improve code readability.
默认 QJsonObject::const_iterator constructor creates an uninitialized iterator. You must initialize it using a QJsonObject function like QJsonObject::constBegin (), QJsonObject::constEnd ()，或 QJsonObject::find () before you can start iterating.
Multiple iterators can be used on the same object. Existing iterators will however become dangling if the object gets modified.
另请参阅 QJsonObject::iterator , 在 Qt 中支持 JSON ，和 JSON 保存游戏范例 .
同义词 std::random_access_iterator_tag indicating this iterator is a random-access iterator.
注意： In Qt versions before 5.6, this was set by mistake to std::bidirectional_iterator_tag .
Constructs an uninitialized iterator.
Functions like key (), value (), and operator++() must not be called on an uninitialized iterator. Use operator=() to assign a value to it before using it.
另请参阅 QJsonObject::constBegin () 和 QJsonObject::constEnd ().
构造副本为 other .
Returns the current item's key.
另请参阅 value ().
Returns the current item's value.
返回
true
if
other
指向与此迭代器不同的项；否则返回
false
.
另请参阅 operator== ().
返回
true
if
other
指向与此迭代器不同的项；否则返回
false
.
另请参阅 operator== ().
Returns the current item's value.
如同 value ().
另请参阅 key ().
Returns an iterator to the item at j positions forward from this iterator. If j is negative, the iterator goes backward.
This operation can be slow for large j 值。
另请参阅 operator- ().
The prefix ++ operator,
++i
, advances the iterator to the next item in the object and returns an iterator to the new current item.
Calling this function on QJsonObject::end () leads to undefined results.
另请参阅 operator-- ().
这是重载函数。
The postfix ++ operator,
i++
, advances the iterator to the next item in the object and returns an iterator to the previously current item.
Advances the iterator by j items. If j is negative, the iterator goes backward.
This operation can be slow for large j 值。
另请参阅 operator-= () 和 operator+ ().
Returns an iterator to the item at j positions backward from this iterator. If j is negative, the iterator goes forward.
This operation can be slow for large j 值。
另请参阅 operator+ ().
The prefix -- operator,
--i
, makes the preceding item current and returns an iterator pointing to the new current item.
Calling this function on QJsonObject::begin () leads to undefined results.
另请参阅 operator++ ().
这是重载函数。
The postfix -- operator,
i--
, makes the preceding item current and returns an iterator pointing to the previously current item.
Makes the iterator go back by j items. If j is negative, the iterator goes forward.
This operation can be slow for large j 值。
另请参阅 operator+= () 和 operator- ().
Returns a pointer to the current item.
返回
true
if
other
points to the same item as this iterator; otherwise returns
false
.
另请参阅 operator!= ().
返回
true
if
other
points to the same item as this iterator; otherwise returns
false
.
另请参阅 operator!= ().
