characteristic:setValueUpdateListener(callback [, object])
Sets or removes the value-update listener callback for read and notification updates. To remove the callback, use nil as callback parameter. Once the listener callback is called the result can be retrieved via getValue(). This function can be called at any time to update the value update listener callback for a discovered characteristic.
|
Parameter |
Type |
Description |
|---|---|---|
|
callback |
in function |
The callback is called once the characteristic value is ready to be retrieved via the getValue() function |
|
object |
in any (optional) |
If a callback is provided, optionally an object can be specified which will be passed as the first parameter to the specified callback function. The object can be of any type except nil. |
callback([object,] characteristic [, error])
The callback function informs when the characteristic value is ready to be retrieved via the getValue() function. The callback should not be used to initiate another read for the same characteristic.
|
Parameter |
Type |
Description |
|---|---|---|
|
object |
in any (optional) |
If an object was provided as a parameter to the function setValueUpdateListener, it will be passed as the first parameter to this callback function |
|
characteristic |
in characteristic object |
The characteristic for which the value can be read |
|
error |
in string (optional) ) |
If successful the parameter will be nil, an error message otherwise |
Introduced in platform.apiLevel = '2.5'