Pass UIImage to Cell of another View Controller - ios

I'm trying to pass the content of a UIImage() variable to the Cell of the next View Controller.
Basically my layout looks like this:
An image is loaded in ControllerA and then saved in a model.
In the next controller, a TableViewCell is loaded.
I want the picture to load inside the cell.
How do I achieve this?
My code:
First part:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Save the poem.
savePoem()
}
func savePoem() {
// Save the poem current completion date.
poem.date = NSDate()
// Save the theme name for the poem.
poem.theme = theme.name
// Save the currently displayed picture.
poem.image = ImageView.image
poem.words = textField.words
// Make the poem object persist.
PoemPersistence.sharedInstance.persistPoem(poem)
}
The cell loads the pic:
func configureWithPoem(poem: Poem) {
themeLabel.text = "#\(poem.theme)"
poemLabel.text = poem.words
pictureImageView.image = poem.image
}
func capturePoemImage() -> UIImage {
// Hide the share button.
shareButton.hidden = true
// Capture a PNG of the view.
UIGraphicsBeginImageContextWithOptions(frame.size, false, 0)
layer.renderInContext(UIGraphicsGetCurrentContext()!)
let containerViewImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
// Show the share button.
shareButton.hidden = false
return containerViewImage
}
cell gets loaded in second controller:
func poemCellWantsToSharePoem(poemCell: PoemCell) {
// Find the poem displayed at this index path.
let indexPath = tableView.mp_indexPathForCell(poemCell)
let poem = poems[indexPath.row]
// Generate the image of the poem.
let poemImage = poemCell.capturePoemImage()

if you want just you use prepareForSegue() to send data to the next UIViewController
- Create the segue to next controller (control + Drag), then give the identifier a name.
Now set up your destination controller by declaring
#IBOutlet weak var imageView:UIImageView!
var image:String ?
override func viewDidLoad()
{
imageView.image = image
}
this image variable will receive data then assigned it to the #IBOutlet.
func prepareForSegue (segue:UIStoryboardSegue, sender:AnyObject?)
{
if segue.identifier == "NAMEOFSEGUEIDENTIFIER"
{
let destinationController = segue.destinationViewController as! NAMEOFTHEDESTIONCONTROLLER
let indexPath = tableView.indexPathForSelectedRow!
// now the data structure that contains your information, use it there
let data = dataContainer[indexPath.row]
// i noticed that you might be using struct so
// let's passed the picture from that specific row to the next conroller
destinationController.image = data.image
}
}
I hope that helps :)

Related

When trying to segue to a view controller from a table view i get this error: Unexpectedly found nil while unwrapping

I have a segue named "hydrogenSegue" from a "hydrogenBoxButton" to a "Hydrogen" view controller. However, I also wanted to implement a table view so I could search for an element. I tried to make the code so when the cell is clicked it will segue over to the element's view. I used hydrogen as an example here.
In my main ViewController.swift file, I have this to transfer the data:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
//If identifier equals the hydrogen element go to the elements Swift file
if segue.identifier == "hydrogenSegue" {
let hydrogenAtomicNumberPassing = segue.destination as! hydrogenViewController
hydrogenAtomicNumberPassing.hydrogenAtomicNumberPassed = hydrogenAtomicNumber
let hydrogenAtomicMassPassing = segue.destination as! hydrogenViewController
hydrogenAtomicMassPassing.hydrogenAtomicMassPassed = hydrogenAtomicMass
}
}
In the hydrogenViewController.swift file I have this:
import UIKit
class hydrogenViewController: UIViewController {
var hydrogenAtomicNumberPassed: Int!
var hydrogenAtomicMassPassed: Float!
#IBOutlet weak var hydrogenInformationLabel: UILabel!
#IBOutlet weak var hydrogenAtomicNumberLabel: UILabel!
#IBOutlet weak var hydrogenAtomicMassLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
//Setting the background color
self.view.backgroundColor = UIColor.gray
//Converting hydrogen's atomic number from an Int to a String
let hydrogenAtomicNumberString = String("\(hydrogenAtomicNumberPassed!)")
hydrogenAtomicNumberLabel.text = "Atomic Number: \(hydrogenAtomicNumberString)"
//Converting hydrogen's atomic mass from a Float to a String
let hydrogenAtomicMassString = String("\(hydrogenAtomicMassPassed!)")
hydrogenAtomicMassLabel.text = "Atomic Mass: \(hydrogenAtomicMassString)"
}
}
I am getting the error at:
let hydrogenAtomicNumberString = String("\(hydrogenAtomicNumberPassed!)")
I'm assuming it would happen to this line also if I fix only that line:
let hydrogenAtomicMassString = String("\(hydrogenAtomicMassPassed!)")
I have this code in my "searchViewController" (the .swift file used for the table view):
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("row selected : \(indexPath.row)")
if indexPath.row == 0 {
let hydrogenSearchSegue = UIStoryboard(name:"Main",
bundle:nil).instantiateViewController(withIdentifier: "hydrogenView") as!
hydrogenViewController
self.navigationController?.pushViewController(hydrogenSearchSegue,
animated:true)
}
}
When I click on the "Hydrogen" cell in the table view it crashes to this error:
Hydrogen cell
The crash
When I click on the "H" button in this image it will take me to the hydrogen view controller:
Image of the Hydrogen Button in the simulator (Top Left)
Image of the Hydrogen View Controller
I want the hydrogen cell to segue over to the hydrogen view controller just like the button can.
When this same issue came up earlier I just had an issue with the name of the segue in the storyboard. However, because there is no visible segue from the table view, I don't know how to fix the issue.
I've tried this:
performSegue(withIdentifier: "hydrogenSegue", sender: nil)
I was thinking that I could just reuse the "hydrogenSegue" from the button to the view controller but I get a SIGABRT error. It just says that there is no segue with the name "hydrogenSegue." It would be best if I could just reuse that segue in a way because everything is already connected but I now found out that the "searchViewController" can't recognize the segue. Any help is appreciated and my main goal is to just get the cell that is clicked on to move over to the element's designated view. I tried to provide as much information as possible without making it to long and if there is any more information needed, I should be able to provide it.
well. first answer
in your hydrogenViewController try with this lines.
var hydrogenAtomicNumberPassed: Int?
var hydrogenAtomicMassPassed: Float?
override func viewDidLoad(){
super.viewDidLoad()
self.viewBackgroundColor = .gray
}
override func viewWillAppear(){
super.viewWillAppear()
if let number = hydrogenAtomicNumberPassed
{
hydrogenAtomicNumberLabel.text = "Atomic Number: \(number)"
}
if let mass = hydrogenAtomicMassPassed
{
hydrogenAtomicMassLabel.text = "Atomic Mass: \(mass)"
}
}
Now, the segues only "lives" between a couple viewControllers, if you have a third view controller, the last will not recognize him.
other thing, you are using segues and navigation controller, from my point of view, it's a bad idea mixed both, I mean, there are specific apps that can use both ways to present views, only is a advice.
if you want to pass data with pushviewcontroller only use this line
if indexPath.row == 0 {
let hydrogenSearchSegue = UIStoryboard(name:"Main",bundle:nil).instantiateViewController(withIdentifier: "hydrogenView") as! hydrogenViewController
hydrogenSearchSegue.VAR_hydrogenViewController = YOURVAR_INYOURFILE
self.navigationController?.pushViewController(hydrogenSearchSegue, animated:true)
}
tell me if you have doubts, and I will try to help you.

Many buttons to a single view controller

im developing an app that utilises many buttons( possibly 20 buttons) on one primary view controller that can are all able to activate a singular picker view within a pop up on a seperate view controller. i don’t think the answer is lots and lots segues. Is there a better approach I should be considering?
I’m thinking - some kind of multiuse segue that can be activated by any of the buttons, but nonidea how this is done.
Appreciate any advice
Mike
Set up all buttons to same action such as:
#IBAction func keyPressed(_ sender:UIButton){
// use button title string
self.keyString = sender.titleLabel?.text as! String
// or tag
self.keyTag= sender.tag?
self.performSegue(withIdentifier: "TheSegue", sender: self)
}
Then you would want to set up the View Controller that you are going to navigate to based on the state of the sender. So you would override the prepare:forSegue method as below.
override func prepare(for segue:UIStoryboardSegue, sender:Any?) {
let destController = segue.destination as! Dest_Controller_Class
// use tag or keyTitle to set controller attributes
// before view is shown
destController.keyTag = self.keyTag
destController.keyString = self.keyString
}
Now once you've navigated to the Dest_Controller_Class, you will have the properties of the button pressed locally in the view controller and could update the view as you see fit:
class Dest_Controller_Class: UIViewController {
var keyString: String?
var keyTag: Int?
#IBOutlet weak var label: UILabel!
override func viewDidLoad() {
if (keyString != nil) {
label.text = keyString;
// or likewise use tag
} else {
label.text = "keyString not set"
}
}
}

Passing data won't update the string

I have a table view with a tap gesture recognizer inside of it and when I double click on the cell, I wanted to pass data from the cell to another view controller. Now it works only once and doesnt update the string in the view controller. The string remains permanent. Now I need help updating the string so that when I try to double tap another cell, the string will update instead of only work once by keeping the value of the string in the view controller constant with that of the first cell tapped. Here is my code.
Code in tableview for double tap gesture recognizer.
func CellTappedTwice(sender: UITapGestureRecognizer!) {
if let index = sender.view?.tag{
if let object = objects?[index]{
if let objectId = object.objectId{
popupViewController.objectId = objectId
}
}
}
self.present(popupViewController, animated: true, completion: nil)
}
Code in view controller:
var objectId : String?
#IBOutlet weak var QrCode: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
if let object = objectId {
let qrcode = DCQRCode(info: object, size: CGSize(width: 170, height: 170))
qrcode.positionStyle = [
(UIImage(named: "RedOuterPosition")!, DCQRCodePosition.topRight),
(UIImage(named: "RedOuterPosition")!, DCQRCodePosition.topLeft),
(UIImage(named: "RedOuterPosition")!, DCQRCodePosition.bottomLeft)
]
qrcode.maskImage = UIImage(named: "RedColors")
QrCode.image = qrcode.image()
print("hello\(objectId)")
}
}
Move the code that handles objectId to your viewWillAppear(_:) method, not viewDidLoad. The viewDidLoad method only gets called once during the life of a view controller, so if you're using the same view controller over and over, you'll only every process objectId the first time it's displayed.

Reloading the collectionView after delete

I'm using firebase. My code works but my issue is when I press the accept button, I want that index to be deleted from the collectionView and I want the table to reload right away right after. I can't use the slide to delete because I need it for another function.
This is in my cell class thats why I did not use self. to call the collectionView. This function is being called by a addTarget() method. I'm thinking maybe passing an indexPath as a parameter, but I don't know how to pass an indexPath.item as a parameter and also how to pass a parameter inside an addTarget() method.
func handleAccept(_ sender: UIButton) {
print("button pressed")
guard let artId = art?.artId else {return}
let approvedRef =
FIRDatabase.database().reference().child("approved_art")
approvedRef.updateChildValues([artId: 1])
let pendingRef =
FIRDatabase.database().reference().child("pending_art").child("\(artId)")
pendingRef.removeValue { (error, ref) in
if error != nil {
return
}
let layout = UICollectionViewFlowLayout()
let pendingArtCollectionViewController =
PendingArtsCollectionViewController(collectionViewLayout: layout)
DispatchQueue.main.async {
pendingArtCollectionViewController.collectionView?.reloadData()
}
}
}
You don't need to pass indexpath as argument, you can get the indexpath of the tableView in button action with the following code :
func handleAccept(_ sender: UIButton) {
let center = sender.center
let rootViewPoint = sender.superview!!.convert(center!, to: self.myTableView)
let currentIndexpath = myTableView.indexPathForRow(at: rootViewPoint)
}

Error trying to transfer data from variable between storyboards

I have a game where I store the value of the high score of a player as "highScore", in the first view controllers.
What I want to do is to try to transfer this variable data, to the second view controller.
I entered in the following code in the first view controller's storyboard.
Btw, highscore2, is the variable that I delcared in the second view controller, to store the data from the first highscore variable.:
override func prepareForSegue(segue: UIStoryboardSegue!, sender:AnyObject!)
{
if (segue.identifier == "segueTest")
{
var svc = segue!.destinationViewController as! viewTwo;
svc.highScore2 = "High Score \(highScore)"
}
}
Now here is the code in my second view controller (viewTwo):
class viewTwo: UIViewController
{
#IBOutlet var highScoretwolbl: UILabel!
var highScore2:String!
override func viewDidLoad() {
highScoretwolbl.text = highScore2
}
}
For some reason, the code compiles, but the high score is not displayed, and is "nil".
Avoid forced unwrapping.
if let svc = segue.destinationViewController as? viewTwo{
svc.highScore2 = "High Score \(highScore)"
}
Then put in a breakpoint and make sure you got to all of these lines.
As stated in other answers, viewDidLoad only gets fired once. Since you
are using a forced unwrapped string, it is initially nil. It (highScore2) won't get a value until you set it which happens after viewDidLoad. Add some print statements so you can see the sequence of events.
Your best option is to use viewWillAppear. This will get fired every time
your view appears. This is what you want.
You don't need to use a force unwrapped variable. Just make a string a
make it empty initially.
override func prepareForSegue(segue: UIStoryboardSegue, sender:AnyObject?)
{
if segue.identifier == "segueTest"
{
if let svc = segue.destinationViewController as? viewTwo {
print("setting score in prepareForSegue")
svc.highScore2 = "High Score \(highScore)"
}
else {
print("something bad happened")
}
}
}
class viewTwo: UIViewController
{
#IBOutlet var highScoretwolbl: UILabel!
// The following uses forced upwrapping which means it could be nil
// if you never set it and your app will crash.
// var highScore2: String!
// Instead, do this:
var highScore2: String = ""
override func viewWillAppear(animated: Bool) {
// putting this here will ensure that every time the screen
// is shown, the label will get set from the string.
highScoretwolbl.text = highScore2
}
}
If I recall correctly, the viewDidLoad method is called only once when the view controller is first initialized. So you are setting the highScoretwolbl variable before highScore2 actually has any data, this is why it is nil.
I would recommend setting the text inside viewWillAppear so it updates every time the segue happens.
So something like
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(true)
highScoretwolbl.text = highScore2
}
Here is a reference to the lifecycle of all the methods of a view controller. View controller lifecycle

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