The QJsonObject::iterator 类提供 STL 样式非常量迭代器为 QJsonObject . 更多...
| 头： | #include <iterator> |
| qmake: | QT += core |
| Since: | Qt 5.0 |
| typedef | iterator_category |
| iterator () | |
| QString | key () const |
| QJsonValueRef | value () const |
| bool | operator!= (const iterator & other ) const |
| bool | operator!= (const const_iterator & other ) const |
| QJsonValueRef | operator* () const |
| iterator | operator+ (int j ) const |
| iterator & | operator++ () |
| iterator | operator++ ( int ) |
| iterator & | operator+= (int j ) |
| iterator | operator- (int j ) const |
| iterator & | operator-- () |
| iterator | operator-- ( int ) |
| iterator & | operator-= (int j ) |
| QJsonValueRef * | operator-> () const |
| bool | operator== (const iterator & other ) const |
| bool | operator== (const const_iterator & other ) const |
The QJsonObject::iterator 类提供 STL 样式非常量迭代器为 QJsonObject .
QJsonObject::iterator allows you to iterate over a QJsonObject and to modify the value (but not the key) stored under a particular key. If you want to iterate over a const QJsonObject , you should use QJsonObject::const_iterator . 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::iterator constructor creates an uninitialized iterator. You must initialize it using a QJsonObject function like QJsonObject::begin (), QJsonObject::end ()，或 QJsonObject::find () before you can start iterating.
Multiple iterators can be used on the same object. Existing iterators will however become dangling once the object gets modified.
另请参阅 QJsonObject::const_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 .
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
points to the same item as this iterator; otherwise returns
false
.
另请参阅 operator!= ().
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::begin () 和 QJsonObject::end ().
Returns the current item's key.
There is no direct way of changing an item's key through an iterator, although it can be done by calling QJsonObject::erase () followed by QJsonObject::insert ().
另请参阅 value ().
Returns a modifiable reference to the current item's value.
You can change the value of an item by using value() on the left side of an assignment.
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.
Returns a modifiable reference to the current item's value.
如同 value ().
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 key ().
Returns an iterator to the item at j positions forward from this iterator. If j is negative, the iterator goes backward.
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.
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.
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.
另请参阅 operator+= () 和 operator- ().
Returns a pointer to a modifiable reference to the current item.
