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iOS

Posted by Alexander Certosimo
Alexander Certosimo
1,774 Points

Checking for nil in textfield of Alert box

Hey all,

So i have an action sheet that then brings up an alert box. From that alert box when "save" is tapped, i want to segue to another view. I had this working with performSegueWithIdentifier() , but i want to make sure the textfield is not empty first, and if it is, pop up another alert box reminding the user to input something in the textfield. Any help with this? Thanks in advance

  @IBAction func showActionSheet(sender: AnyObject) {
        let actionSheetController: UIAlertController = UIAlertController(title: nil, message:   "What would you like to do?", preferredStyle: .ActionSheet)

         //Create and add the Cancel action
        let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel) { action -> Void in
         }
        actionSheetController.addAction(cancelAction)

        //Create and add first option action
        let createNewDeckAction: UIAlertAction = UIAlertAction(title: "Create new question deck", style: .Default) { action -> Void in self.showAlertTapped()

        }
            actionSheetController.addAction(createNewDeckAction)
            self.presentViewController(actionSheetController, animated: true, completion: nil)


    }



    func showAlertTapped() {
        //Create the AlertController
        let actionSheetController: UIAlertController = UIAlertController(title: "New questions deck", message: "Enter a name for your questions deck", preferredStyle: .Alert)

        //Create and add the Cancel action
        let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel) { action -> Void in

        }
        actionSheetController.addAction(cancelAction)

        //Create and an option action
        let saveAction: UIAlertAction = UIAlertAction(title: "Save", style: .Default) { action -> Void in
            //self.shouldPerformSegueWithIdentifier("saveSegue", sender: self)
        }
        actionSheetController.addAction(saveAction)

        //Add a text field
        actionSheetController.addTextFieldWithConfigurationHandler { textField -> Void in
         textField.textColor = UIColor.blueColor()



        }

        //Present the AlertController
        self.presentViewController(actionSheetController, animated: true, completion: nil)

    }

1 Answer

Jhoan Arango
Jhoan Arango
14,575 Points
Jhoan Arango
Jhoan Arango
14,575 Points

Perhaps you can do something like this, on your showAlertTapped() function.

func showAlertTapped() {
    var check = true

    //Create the AlertController
    let actionSheetController: UIAlertController = UIAlertController(title: "New questions deck", message: "Enter a name for your questions deck", preferredStyle: .Alert)

    //Create and add the Cancel action
    let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel) { action -> Void in

    }
    actionSheetController.addAction(cancelAction)

    //Create and an option action
    let saveAction: UIAlertAction = UIAlertAction(title: "Save", style: .Default) { action -> Void in
        if check == false {
        //self.shouldPerformSegueWithIdentifier("saveSegue", sender: self)
        }
        else {
            // Make another alert
        }
    }
    actionSheetController.addAction(saveAction)

    //Add a text field
    actionSheetController.addTextFieldWithConfigurationHandler { textField -> Void in
        textField.textColor = UIColor.blueColor()

        if textField.text != "" {
            check = false
        }        
    }

    //Present the AlertController
    self.presentViewController(actionSheetController, animated: true, completion: nil)

}
Jhoan Arango
Jhoan Arango
14,575 Points

If not, then you would have to conform to the UITextFieldDelegate, and use delegation to know when a user is typing something in the textField.

Let me know if this works. Or if I can help more.

Alexander Certosimo
Alexander Certosimo
1,774 Points

Hey Jhoan,

Thanks for the quick help. So i thought i had it working, at first it wasnt doing anything for me, not popping up the second alert box, nor segueing to the next view. Then i remembered a past discussion we had where changing nil to "" worked. I tried that, but then it would ONLY pop up the second alert box no matter if the textfield was empty or not.

Should i be doing something with the shouldPerformSegueWithIdentifer method? or should i be leaving it as is above?

Jhoan Arango
Jhoan Arango
14,575 Points

Did you try my code above ? And if so what is it doing ?

Jhoan Arango
Jhoan Arango
14,575 Points

I just modified the code, try it. I don't see why it shouldn't work.

Alexander Certosimo
Alexander Certosimo
1,774 Points

Hi Jhoan,

Was messing around trying to get it to work, but still having no luck. If its set to "" it will give me my invalid entry alert no matter what, if i set it to nil, it will segue to my next view no matter what. I am going to post my code in case i am doing something wrong. 

 func showAlertTapped() {
        var check = true

        //Create the AlertController
        let actionSheetController: UIAlertController = UIAlertController(title: "New questions deck", message: "Enter a name for your questions deck", preferredStyle: .Alert)

        //Create and add the Cancel action
        let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel) { action -> Void in

        }
        actionSheetController.addAction(cancelAction)

        let saveAction: UIAlertAction = UIAlertAction(title: "Save", style: .Default) { action -> Void in

            if check == false {
                self.performSegueWithIdentifier("saveSegue",sender: self)


            }

            else{

                let actionSheetController: UIAlertController = UIAlertController(title: nil, message: "Please enter a valid name", preferredStyle: .Alert)


                let cancelAction: UIAlertAction = UIAlertAction(title: "Ok", style: .Default) { action -> Void in

                }
                actionSheetController.addAction(cancelAction)




                //Present the AlertController
                self.presentViewController(actionSheetController, animated: true, completion: nil)
            }



        }
              actionSheetController.addAction(saveAction)

             //Add a text field
             actionSheetController.addTextFieldWithConfigurationHandler { textField -> Void in
                      if textField.text != "" {
                          check = false
                    }

                 textField.textColor = UIColor.blueColor()



               }

             //Present the AlertController
             self.presentViewController(actionSheetController, animated: true, completion: nil)

    }