QPointingDeviceUniqueId Class
QPointingDeviceUniqueId identifies a unique object, such as a tagged token or stylus, which is used with a pointing device. 更多...
| 头文件: | #include <QPointingDeviceUniqueId> |
| qmake: | QT += gui |
| 开始支持版本: | Qt 5.8 |
属性
- numericId : const qint64
公有函数
| QPointingDeviceUniqueId() | |
| bool | isValid() const |
| qint64 | numericId() const |
静态公有成员
| QPointingDeviceUniqueId | fromNumericId(qint64 id) |
相关非成员
| uint | qHash(QPointingDeviceUniqueId key, uint seed = 0) |
| bool | operator!=(QPointingDeviceUniqueId lhs, QPointingDeviceUniqueId rhs) |
| bool | operator==(QPointingDeviceUniqueId lhs, QPointingDeviceUniqueId rhs) |
详细描述
QPointingDeviceUniqueId identifies a unique object, such as a tagged token or stylus, which is used with a pointing device.
QPointingDeviceUniqueIds can be compared for equality, and can be used as keys in a QHash. You get access to the numerical ID via numericId(), if the device supports such IDs. For future extensions, though, you should not use that function, but compare objects of this type using the equality operator.
This class is a thin wrapper around an integer ID. You pass it into and out of functions by value.
This type actively prevents you from holding it in a QList, because doing so would be very inefficient. Use a QVector instead, which has the same API as QList, but more efficient storage.
属性
numericId : const qint64
This property holds the numeric unique ID of the token represented by a touchpoint
If the device provides a numeric ID, isValid() returns true, and this property provides the numeric ID; otherwise it is -1.
You should not use the value of this property in portable code, but instead rely on equality to identify pointers.
访问函数:
| qint64 | numericId() const |
参见 isValid().
成员函数
QPointingDeviceUniqueId::QPointingDeviceUniqueId()
Constructs an invalid unique pointer ID.
[static] QPointingDeviceUniqueId QPointingDeviceUniqueId::fromNumericId(qint64 id)
Constructs a unique pointer ID from numeric ID id.
bool QPointingDeviceUniqueId::isValid() const
Returns whether this unique pointer ID is valid, that is, it represents an actual pointer.
相关非成员
uint qHash(QPointingDeviceUniqueId key, uint seed = 0)
Returns the hash value for key, using seed to seed the calculation.
This function was introduced in Qt 5.8.
bool operator!=(QPointingDeviceUniqueId lhs, QPointingDeviceUniqueId rhs)
Returns whether the two unique pointer IDs lhs and rhs identify different pointers (true) or not (false).
This function was introduced in Qt 5.8.
bool operator==(QPointingDeviceUniqueId lhs, QPointingDeviceUniqueId rhs)
Returns whether the two unique pointer IDs lhs and rhs identify the same pointer (true) or not (false).
This function was introduced in Qt 5.8.