How to read/write from one IOS App set up with firebase, to another firebase database contained in another firebase project? Swift 3
问题 I have a Firebase database connected to my IOS app with the GoogleService-Info.plist. In AppDelegate I configured the App FIRApp.configure(). I could read/write data. Now, from within this IOS app, I would like to access another FireBase Database brevCustomer . For some reason let dbRef from viewDidLoad has a flag in Xcode saying this 'immutable value dbRef was never used' and the app crashes on the first line in fun startObserving() dbRef.observe(.value, with: { (snapshot: FIRDataSnapshot)