如何观察Backendless数据库的属性变化？ - 斯威夫特

Question

I have this code in Swift 3 to get backendless user so I can get his/her properties:

            let whereClause = "objectId = '\(userId)'"

            let query = BackendlessDataQuery()
            query.whereClause = whereClause

            let data = Backendless.sharedInstance().persistenceService.of(BackendlessUser.ofClass())

            data?.find(query, response: { (result) in

                let user = result?.data.first as! BackendlessUser

                myLabel.text = user.getProperty("firstName") as! String

          })

The code is working fine but my question is how to observe the property changes ? is there a way if the value of property firstName changed I can update my label automatically ?

Answer 1

The use-case you describe is not really as simple as it may seem, but it's definitely possible.

You can capture any changes in Users table by creating an afterUpdate event handler . From there you could publish a message to some dedicated channel in messaging service .

At the same time, your application should be subscribed to this same channel . This way you could update your UI when the appropriate message is received.