SWIFT: Parse data is deleted when UIButton Action is performed - ios

Question

Here are the steps that I'm taking -
Step 1: I enter values in the following fields, and they get saved in the Parse table. Works perfect.
Step 2: I access this screen again, and click 'Submit' again without editing the fields, and the Parse table row is deleted.
I am trying to figure out why this is happening. The desired functionality is that when the user loads this screen for the first time, the fields are blank. Once this screen is loaded thereafter, the existing values are displaying the fields, and if the user edits the fields and clicks 'Submit', the values will chance.
This is my code for this particular view controller -
import UIKit
import Parse
class RSVPViewController: UIViewController {
/*----------- ~ OUTLETS AND ACTIONS ~ -----------*/
//View Controller Title Bar Outlets
#IBOutlet weak var usernameTitle: UIBarButtonItem!
#IBOutlet weak var menuTitle: UIBarButtonItem!
//View Controller Body Outlets
#IBOutlet weak var label1: UILabel!
#IBOutlet weak var label2: UILabel!
#IBOutlet weak var label3: UILabel!
#IBOutlet weak var label4: UILabel!
#IBOutlet weak var label1Field: UITextField!
#IBOutlet weak var label2Field: UITextField!
#IBOutlet weak var label3Field: UITextField!
#IBOutlet weak var label4Field: UITextField!
//View Controller Body Actions
#IBAction func submitButton(sender: AnyObject) {
let query = PFQuery(className:"RSVPData")
query.whereKey("username", equalTo: (PFUser.currentUser()?.username)!)
query.findObjectsInBackgroundWithBlock { (objects: [PFObject]?, error: NSError?) -> Void in
if error == nil {
if let objects = objects! as? [PFObject] {
for object in objects {
object.deleteInBackground()
}
}
} else {
print(error)
}
}
let RSVPData = PFObject(className: "RSVPData")
RSVPData["label1"] = label1Field.text
RSVPData["label2"] = label2Field.text
RSVPData["label3"] = label3Field.text
RSVPData["label4"] = label4Field.text
RSVPData["username"] = PFUser.currentUser()?.username
RSVPData.saveInBackgroundWithBlock {
(success: Bool, error: NSError?) -> Void in
if (success) {
if let error = error {
if let errorString = error.userInfo["error"] as? String {
self.displayAlert("Failed", message: errorString)
}
} else {
self.performSegueWithIdentifier("RSVPToMain", sender: self)
}
} else {
// There was a problem, check error.description
}
}
}
/*----------- ~ MAIN THREAD ~ -----------*/
override func viewDidLoad() {
super.viewDidLoad()
//Run title bar function
TitleBar()
label1.text = "Label 1"
label2.text = "Label 2"
label3.text = "Label 3"
label4.text = "Label 4"
let query = PFQuery(className:"RSVPData")
query.whereKey("username", equalTo: (PFUser.currentUser()?.username)!)
query.findObjectsInBackgroundWithBlock { (objects: [PFObject]?, error: NSError?) -> Void in
if error == nil {
if let objects = objects! as? [PFObject] {
for object in objects {
self.label1Field.text = object["label1"] as? String
self.label2Field.text = object["label2"] as? String
self.label3Field.text = object["label3"] as? String
self.label4Field.text = object["label4"] as? String
}
}
} else {
print(error)
}
}
}
/*----------- ~ FUNCTIONS ~ -----------*/
//Function containing all title bar instructions
func TitleBar() {
/*----------- ~ NAVIGATION BAR (USER INTERFACE) ~ -----------*/
//Set the navigation bar tet color and size
let nav = self.navigationController?.navigationBar
nav?.titleTextAttributes = [NSFontAttributeName: UIFont(name: "HelveticaNeue-Light", size: 20)!, NSForegroundColorAttributeName: UIColor(red: 255/255, green: 255/255, blue: 255/255, alpha: 1.0)]
/*----------- ~ OUTLET - 'usernameTitle' ~ -----------*/
//Set the 'usernameTitle' font and size
usernameTitle.setTitleTextAttributes([NSFontAttributeName: UIFont(name: "Arial", size: 11)!], forState: UIControlState.Normal)
//Set the 'usernameTitle' outlet to the current user
usernameTitle.title = PFUser.currentUser()?.username
}
//Function to display an alert
func displayAlert(title: String, message: String) {
let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)
}
SOLUTION:
#IBAction func submitButton(sender: AnyObject) {
let query = PFQuery(className:"RSVPData")
query.whereKey("username", equalTo: (PFUser.currentUser()?.username)!)
query.findObjectsInBackgroundWithBlock { (object: [PFObject]?, error: NSError?) -> Void in
if error == nil {
if object!.count > 0 {
if let object = object! as? [PFObject] {
for object in object {
object["label1"] = self.label1Field.text
object["label2"] = self.label2Field.text
object["label3"] = self.label3Field.text
object["label4"] = self.label4Field.text
object.saveInBackground()
}
self.performSegueWithIdentifier("RSVPToMain", sender: self)
}
} else if object?.count == 0 {
let RSVPData = PFObject(className: "RSVPData")
RSVPData["label1"] = self.label1Field.text
RSVPData["label2"] = self.label2Field.text
RSVPData["label3"] = self.label3Field.text
RSVPData["label4"] = self.label4Field.text
RSVPData["username"] = PFUser.currentUser()?.username
RSVPData.saveInBackgroundWithBlock {
(success: Bool, error: NSError?) -> Void in
if (success) {
if let error = error {
if let errorString = error.userInfo["error"] as? String {
self.displayAlert("Failed", message: errorString)
}
} else {
self.performSegueWithIdentifier("RSVPToMain", sender: self)
}
} else {
// There was a problem, check error.description
}
}
}
} else {
print(error)
}
}
}

Answer 1

I do not need to delete the row if it exists. Instead of deleting the row, you can just update with the new values that you get from the user. Here is a sample from parse.com website on how to update an existing object. Let me know if you still have a question and i will try it in Xcode and update it with your code. https://parse.com/docs/ios/guide
var query = PFQuery(className:"GameScore")
query.getObjectInBackgroundWithId("xWMyZEGZ") {
(gameScore: PFObject?, error: NSError?) -> Void in
if error != nil {
print(error)
} else if let gameScore = gameScore {
gameScore["cheatMode"] = true
gameScore["score"] = 1338
gameScore.saveInBackground()
}
}
You can use your code and see comments bellow.
query.whereKey("username", equalTo: (PFUser.currentUser()?.username)!)
query.findObjectsInBackgroundWithBlock { (objects: [PFObject]?, error: NSError?) -> Void in
if error == nil {
if let objects = objects! as? [PFObject] {
//see comments bellow
//for object in objects {
//object.deleteInBackground()
// }
}
} else {
print(error)
}
}
When you get the array of objects, you would check if there is only one object in the array to make sure there is only one row for that user and then do object["sangeet"] = label1Field.text
update all the fields and do object.saveInBackground();
==========
Update
You can create a new row when objects return nil. I am thinking you should be able excuse save operation inside of the findObjectsInBackgroundWithBlock block I am not very familiar with swift so i copy pasted your code and it should work. Let me know if you still having issues.
let query = PFQuery(className:"RSVPData")
query.whereKey("username", equalTo: (PFUser.currentUser()?.username)!)
query.findObjectsInBackgroundWithBlock { (objects: [PFObject]?, error: NSError?) -> Void in
if error == nil {
if let objects = objects! as? [PFObject] {
for object in objects {
object.deleteInBackground()
}
}else{
//assuming that object is nil and there is no record for that user
//you would then add the user and information into the database
let RSVPData = PFObject(className: "RSVPData")
RSVPData["sangeet"] = label1Field.text
RSVPData["tibetan"] = label2Field.text
RSVPData["hindu"] = label3Field.text
RSVPData["reception"] = label4Field.text
RSVPData["username"] = PFUser.currentUser()?.username
RSVPData.saveInBackgroundWithBlock {
(success: Bool, error: NSError?) -> Void in
if (success) {
if let error = error {
if let errorString = error.userInfo["error"] as? String {
self.displayAlert("Failed", message: errorString)
}
} else {
self.performSegueWithIdentifier("RSVPToMain", sender: self)
}
} else {
// There was a problem, check error.description
}
}
}
} else {
print(error)
}
}

Answer 2

Seems to me that you do delete the row if the username is the same value as your PFUser's username. I have not used Parse before but object.deleteInBackground() looks like a delete to me.
let query = PFQuery(className:"RSVPData")
query.whereKey("username", equalTo: (PFUser.currentUser()?.username)!)
query.findObjectsInBackgroundWithBlock { (objects: [PFObject]?, error: NSError?) -> Void in
if error == nil {
if let objects = objects! as? [PFObject] {
for object in objects {
object.deleteInBackground()
}
}
}
}
So I guess you only delete the entry if you use the same user twice.