centralManagerdidDiscoveradvertisementDatarssi

centralManagerdidDiscoveradvertisementDatarssi is a method in the Core Bluetooth framework for iOS, macOS, watchOS, and tvOS. It is part of the CBCentralManagerDelegate protocol. This method is invoked by the central manager object when it discovers a peripheral advertising data. The discovery can be a result of a scanning operation initiated by the central manager.

The method receives several parameters: centralManager, which is the central manager object that discovered the peripheral; advertisementData, a dictionary containing the advertising data from the peripheral; and rssi, an NSNumber object representing the received signal strength indicator of the peripheral. The advertisementData dictionary can contain various information such as the peripheral's name, local name, service UUIDs, manufacturer specific data, and transmission power level. The rssi value indicates how strong the signal is from the peripheral, with higher absolute values meaning a weaker signal and values closer to zero indicating a stronger signal.

This method is crucial for discovering nearby Bluetooth low energy devices. Developers use this callback to filter peripherals based on their advertising data or signal strength, and to initiate connections to desired devices. For example, an application might only want to connect to peripherals that advertise a specific service UUID or that are within a certain range determined by their rssi. The frequency with which this method is called depends on the scanning interval and window configured for the central manager.