Unpinning HomeKit accessory - ios

Question

The HomeKit Accessory simulator as a wee little botton that allows to unfair the device.
Given it's an accessory simulator I presume that there are some hardware programming specifications that allow to write an un-pairing function.
However, it could make sense to implement this also as part of the HomeKit framework and allow client developers to do it via the HomesController class (and derivates).
--> short version:
Is there any method in HMService or HMCharacteristic or in the HomeKit framework to unpair a characteristic/service from a home?

Answer 1

Service or Characteristic can not be unpair, practically its not require to do.
One can unpair Accessory from home.
You can call method of HMHome class to remove/unpair accessory.
- (void)removeAccessory:(HMAccessory *)accessory
completionHandler:(void (^)(NSError *error))completion;
And Pairing - Reset button is given in Homekit Accessory Simulator for an option, you can always unpair the accessory from an iOS app.
Reset may require if you don't have the same device at a time or the Homekit configuration is reseted from settings in iOS app.

Answer 2

Unpairing is equivalent to essentially removing that accessory from under a HomeKit home (HMHome). That can be achieved by using the api call under HMHome (could be triggered by a button click from your view controller let's say):
Sample code:
[yourHMHome removeAccessory:accessory_ completionHandler:^(NSError *error) {
if (error) {
//Handle your error here.
} else {
//Removing, or here, un-pairing was successful, do anything else
//Example
[[YourExampleHomeStore sharedStore] updateAccessoryDelegates];
YourCompletionHandler(error);
}
}];
That answers your question regarding un-pairing. HMService and HMCharacteristic is conceptually different. If you'd like to update the value of a (writeable) HMCharacteristic, then you'd search for that HMCharacteristic in the available HMServices. Remember, the available HMServices and thus HMCharacteristics on an accessory will be completely different based on its paired state. Most read or writes and 'paired-read' and 'paired-write', and when in un-paired state, you can only read the 'accessory information service' (name, model etc.)
Now, presuming that you'd like to read or change (write) the value of a HMCharacteristic, let's say it's the serial number, the steps would be:
Get the pertinent HMCharacteristic
Sample code for serial number could be something like this:
Note: Returns empty string if accessory is unreachable.
+(NSString *)getSerialNumberFromHMAccessory:(HMAccessory *)accessory
{
if (!accessory || !accessory.reachable) { return #""; }
for (HMService *service in accessory.services) {
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"%K like %#", #"characteristicType", HMCharacteristicTypeSerialNumber];
NSArray *result = [service.characteristics filteredArrayUsingPredicate:predicate];
if (result && [result count] > 0 && [result[0] isKindOfClass:[HMCharacteristic class]]) {
HMCharacteristic *serialNumChar = (HMCharacteristic *)result[0];
NSString *serialNum = [serialNumChar valueForKey:#"value"];
if (serialNum && [serialNum length] > 0) {
NSLog(#"Found serial number: %# for accessory named \"%#\"", serialNum, accessory.name);
return serialNum;
}
}
}
return #"";
}
Once you've found your desired HMCharacteristic, you can make HomeKit api calls to further your interest (like update value etc.). Here, since serial number is not writeable, you need to be content with just reading it.
Anyway, probably ranted a tad too long and digressed from the main question. Hope this helps you man. Cheers.