Remove optional from string getting from NSNotification

Question

I m getting a string from NSNotification,but facing issue of optional keyword attached with the given string,wants to remove OPTIONAL keyword from string,here is my code:

func getAlertMsg(notification:NSNotification!){
        if let strAlert = notification?.object.debugDescription{
            print(strAlert)
            Helper .showAsAlert(strMessage: strAlert, VC: self)
        }
    }

Response

{
"status": true,
"message": "User created",
"user_detail":{}
}

Wouldn’t it be easier to **send** a non-optional string? And why is the parameter IUO? — vadian, Apr 05 '18 at 08:22
Use non optional var, or learn how to "unwrap optional" (that's the key words to search) in Swift (that's quite basic and very useful knowledge). — Larme, Apr 05 '18 at 08:23
Possible duplicate of [What is an "unwrapped value" in Swift?](https://stackoverflow.com/questions/24034483/what-is-an-unwrapped-value-in-swift) — Tamás Sengel, Apr 05 '18 at 08:23
The `notification.object` is optional `Any`. What object are you sending? and why are you using it's `debugDescription`? — staticVoidMan, Apr 05 '18 at 08:24
@Zaphod: result is Optional(My Alert) and i want to remove Optional keyword — priyanshu, Apr 05 '18 at 08:25
@mag_zbc The string in `debugDescription` can already contain literal `”Optional(”` — vadian, Apr 05 '18 at 08:26
@staticVoidMan: I m sending a string from one class to other and in order to get that string from notification object im using debugDescription — priyanshu, Apr 05 '18 at 08:26
Show the code where you create the string in the first place. — Fogmeister, Apr 05 '18 at 08:28
@priyanshu We're getting somewhere. Show how are you sending the string — mag_zbc, Apr 05 '18 at 08:28
getting from JSON response: let strMessage = responseVal .value(forKey: "message") as? String NotificationCenter.default.post(name: NSNotification.Name(rawValue: "RegAlertMsg"), object: strMessage!) — priyanshu, Apr 05 '18 at 08:33
@priyanshu much more code is needed. What is `responseVal`, how is it created? And don't post code in comments, edit the original question — mag_zbc, Apr 05 '18 at 08:36
use ! to force unwrapping string value. And make sure that data type of that key is String — Mehul Sojitra, Apr 05 '18 at 11:41

staticVoidMan · Accepted Answer · 2018-04-05T08:57:01.513

-1

For your current code. It should be:

func getAlertMsg(notification: NSNotification) {
    if let string = notification.object as? String {
        Helper.showAsAlert(strMessage: string, VC: self)
    }
}

Also, your notification post should be:

let strMessage = responseVal.value(forKey: "message") as? String
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "RegAlertMsg"), 
                                object: strMessage)

Just pass strMessage. Don't bang (!) it or you app will crash when responseVal.value(forKey: "message") as? String fails.

edited Apr 05 '18 at 08:57

answered Apr 05 '18 at 08:28

staticVoidMan

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He already uses optional chaining to unwrap the string - `if let strAlert = ...` – mag_zbc Apr 05 '18 at 08:30
1

@mag_zbc But the optional chaining is done at the wrong place. – staticVoidMan Apr 05 '18 at 08:31
@mag_zbc Anyways, i've updated my answer. But `object` in a `NSNotification` is the final optional one. He just confused everyone by using `NSNotification!` and then `notification?.object.debugDescription`. – staticVoidMan Apr 05 '18 at 08:54
@priyanshu does this answer work for you because I might delete it if it's not of any help – staticVoidMan Apr 06 '18 at 12:44
@staticVoidMan: Hi,it helps actually and what i was using debugDescription which gives me optional so i have used only notification?.object.By the way Thanks a lot !!! – priyanshu Apr 09 '18 at 07:21
@priyanshu My pleasure :) – staticVoidMan Apr 09 '18 at 08:56

score -3 · Answer 2 · answered Apr 05 '18 at 08:52

I have Accessed Object From Notification Like This :

@objc func updateActivityDetailWithUserEvent(notification: NSNotification){ //do stuff

    print("notification obj is ",notification)

    let activityData:[String: ActivityFeed] = notification.object  as! [String: ActivityFeed]
    activityObj = activityData ["activityUpdated"]!
    DispatchQueue.main.async {

    //Update UI From Main Thread
        self.setUpdatedCell()


    }

}

// Way to Post Notification and Passing Dictionary as Parameter :

Call It from Your method from where you like to post Notification with Dictionary parameter:

let activityData:[String: ActivityFeed] = ["activityUpdated": activityFeedObj]

    NotificationCenter.default.post(name: NSNotification.Name(rawValue: "activityUpdated"), object: activityData)

Here I am taking Dictionary Object from Notification that i have passed for while generation NSNotification, you can follow similar approach for Getting String Value

Too bad I can only use one downvote for that force-unwrapping — mag_zbc, Apr 05 '18 at 08:56
i have added sample just to give u idea about how i have access object from notification , you can change it as per your requirements. — A.sharma, Apr 05 '18 at 09:16

Remove optional from string getting from NSNotification

2 Answers2