QLowEnergyCharacteristic Class

See also QLowEnergyService, QLowEnergyDescriptor

flags QLowEnergyCharacteristic::PropertyTypes

This enum describes the properties of a characteristic.

It is not recommended to set both Notify and Indicate properties on the same characteristic as the underlying Bluetooth stack behaviors differ from platform to platform. Please see QLowEnergyCharacteristic::clientCharacteristicConfiguration

The PropertyTypes type is a typedef for QFlags<PropertyType>. It stores an OR combination of PropertyType values.

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Construct a new QLowEnergyCharacteristic. A default-constructed instance of this class is always invalid.

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Construct a new QLowEnergyCharacteristic that is a copy of other.

The two copies continue to share the same underlying data which does not detach upon write.

Destroys the QLowEnergyCharacteristic object.

Returns the Client Characteristic Configuration Descriptor or an invalid QLowEnergyDescriptor instance if no Client Characteristic Configuration Descriptor exists.

BTLE characteristics can support notifications and/or indications. In both cases, the peripheral will inform the central on each change of the characteristic's value. In the BTLE attribute protocol, notification messages are not confirmed by the central, while indications are confirmed. Notifications are considered faster, but unreliable, while indications are slower and more reliable.

If a characteristic supports notification or indication, these can be enabled by writing special bit patterns to the Client Characteristic Configuration Descriptor. For convenience, these bit patterns are provided as QLowEnergyCharacteristic::CCCDDisable, QLowEnergyCharacteristic::CCCDEnableNotification, and QLowEnergyCharacteristic::CCCDEnableIndication.

Enabling e.g. notification for a characteristic named mycharacteristic in a service called myservice could be done using the following code.

auto cccd = mycharacteristic.clientCharacteristicConfiguration();
if (!cccd.isValid()) {
    // your error handling
    return error;
}
myservice->writeDescriptor(cccd, QLowEnergyCharacteristic::CCCDEnableNotification);

This function was introduced in Qt 6.2.

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Returns the descriptor for uuid or an invalid QLowEnergyDescriptor instance.

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Returns the list of descriptors belonging to this characteristic; otherwise an empty list.

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Returns true if the QLowEnergyCharacteristic object is valid, otherwise returns false.

An invalid characteristic object is not associated with any service (default-constructed) or the associated service is no longer valid due to a disconnect from the underlying Bluetooth Low Energy device, for example. Once the object is invalid it cannot become valid anymore.

Returns the human-readable name of the characteristic.

The name is based on the characteristic's uuid() which must have been standardized. The complete list of characteristic types can be found under Bluetooth.org Characteristics.

The returned string is empty if the uuid() is unknown.

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Returns the properties of the characteristic.

The properties define the access permissions for the characteristic.

Returns the UUID of the characteristic if isValid() returns true; otherwise a null UUID.

Returns the cached value of the characteristic.

If the characteristic's properties() permit writing of new values, the value can be updated using QLowEnergyService::writeCharacteristic().

The cache is updated during the associated service's detail discovery, a successful read/write operation or when an update notification is received.

The returned QByteArray always remains empty if the characteristic does not have the read permission. In such cases only the QLowEnergyService::characteristicChanged() or QLowEnergyService::characteristicWritten() may provice information about the value of this characteristic.

Makes a copy of other and assigns it to this QLowEnergyCharacteristic object. The two copies continue to share the same service and controller details.

Bit pattern to write into Client Characteristic Configuration Descriptor to disable both notification and indication.

This documentation was introduced in Qt 6.2.

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Bit pattern to write into Client Characteristic Configuration Descriptor to enable indication.

This documentation was introduced in Qt 6.2.

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Bit pattern to write into Client Characteristic Configuration Descriptor to enable notification.

This documentation was introduced in Qt 6.2.

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Returns true if a and b are not equal; otherwise false.

Two QLowEnergyCharcteristic instances are considered to be equal if they refer to the same characteristic on the same remote Bluetooth Low Energy device or both instances have been default-constructed.

Returns true if a is equal to b, otherwise false.

Two QLowEnergyCharacteristic instances are considered to be equal if they refer to the same characteristic on the same remote Bluetooth Low Energy device or both instances have been default-constructed.