Querying in Realm (using Swift)

Question

I'm toying with realm.io. I've written a couple of objects, and now I want to query for them. My data class:

class Sample : RLMObject {
    dynamic var sampleKey : String = ""
}

and my query code

@IBAction func readLocalRecord(sender: UIButton) {

    let s : NSString = NSString.stringWithString("sampleKey == SampleValue")
    let p : NSPredicate = NSPredicate(format: "sampleKey = %@", argumentArray: NSArray(object: NSString.stringWithString("SampleValue")))

    // the following throws exception, that I cannot catch in Swift:
    //   'Unsupported predicate value type', reason: 'Object type any not supported'
    let r = Sample.objectsWithPredicate(p)
}

The webside, and the header of RLMObject, indicate that I should be able to say Sample.objectsWhere("sampleKey = 'SampleValue'") (or similar), but objectsWhere gives a compile error complaining the function isn't there, and there's no autocomplete for it. So I tried with objectsForPredicate instead, but this says that the type 'any' (digging through the headers, I find that this equals ObjC's 'id' type in Realm lingo). What am I doing wrong here? I try to be veery explicit, being sure to use NSString instead of String and NSArray instead of Array, but still something is interpreted as 'id' instead of a spesific type.

Any suggestions?

Cheers

-Nik

Answer 1

Your code works fine for me with Xcode 6 beta 5. Incidentally, you don't need to explicitly use NSArray and NSString here - Swift will bridge to objective-c types for you. The following works for me and prints out the object I'd expect to see:

import Realm

class Sample : RLMObject {
    dynamic var sampleKey : String = ""
}

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func readLocalRecord() {

        // create some sample records
        RLMRealm.defaultRealm().beginWriteTransaction()
        var s = Sample()
        s.sampleKey = "Testing"
        RLMRealm.defaultRealm().addObject(s)
        var s2 = Sample()
        s2.sampleKey = "SampleValue"
        RLMRealm.defaultRealm().addObject(s2)
        RLMRealm.defaultRealm().commitWriteTransaction()

        let p : NSPredicate = NSPredicate(format: "sampleKey = %@", argumentArray: [ "SampleValue" ])

        let r = Sample.objectsWithPredicate(p)
        println(r)
    }

    func application(application: UIApplication!, didFinishLaunchingWithOptions launchOptions: NSDictionary!) -> Bool {

        readLocalRecord()

        return true
    }
}

Output is:

RLMArray <0x7fe8241218c0> (
    [0] Sample {
        sampleKey = SampleValue;
    }
}

Note that Realm's objectsWithPredicate method returns you a Realm array, not a normal Array.