I have tableView (A) responsible for listing items CoreData and viewController (B) to add new item. To create a ViewController (B) custom, they chose to use the following Present Modally to use presentation Over Current Context to enable transparent background and be able to apply the blur.
From tableView (A) press the button to add a new item, the viewController (B) appears.
Add a new item and saved in CoreData
The viewController (B) execute self.dismissViewControllerAnimated(true, completion: nil) and the display returns to the tableView (B)
The problem is that the table view does not update the data.
Following a post from Stack Overflow resulting in code:
override func viewDidAppear(animated: Bool) {
self.loadData()
}
But at the back of viewController (B), nothing happens in Xcode does not pass the lines of viewDidAppear.
Can anyone help me?
Try this:
override func viewDidAppear(animated: Bool)
{
self.yourTableViewName.reloadData()
}
Related
I have a table view in one view controller. I want to update the table view from another VC. I'm doing this using NotificationCenter like this:
In the table view VC:
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(self.updateTableView), name: NSNotification.Name(rawValue: "updateTableView"), object: nil)
}
#objc func updateTableView() {
print("in func")
DispatchQueue.main.async {
self.listTV.reloadData()
}
}
In the opened VC:
func reloadTV() {
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "updateTableView"), object: nil)
}
The print works, but the table view doesn't reload. I can only see it changing if I dismiss the VC with the table view and open it again.
I've followed the suggestions of other answers which is to use DispatchQueue, but that didn't make a difference. What am I missing?
Many thanks!
I would consider doing this by protocol and delegate instead of notifications...
This is how I do it.
When you call tableView.reloadData(). It has no effect if the tableView is hidden (isHidden == true). I believe the behavior is also the same when the tableView is effectively hidden by another ViewController (so effectively hidden).
Solution: A suggestion is to reload the tableView when the view is shown again. Few ways to do that.
one is in viewDidAppear (depends on how you transitioned between ViewControllers),
or
you can keep a reference to the tableView and after you dismiss the second ViewController (in which you were sending the notification) you provide the callback to reload the tableView. Roughly like the snippet, with self being the secondViewController you transitioned to. Dismiss that view
self.dismiss(animated: true, completion: {
self.tableView.reloadData()
}
or you can still use your notification and setup a flag and when the viewDidAppear, you then reloadData() inside viewDidAppear. However for this to work, you need to ensure that viewDidAppear is always called when the view is shown again (this will depend on how you transitioned between views).Simply override that method and print to verify.
There are other ways but the bottom line is tableView.reloadData() will be ignored if it is called when the tableView is not visible on the screen. My guess is it's an optimization made by Apple (no need to reload if no table is showing) or maybe a bug. I think they'll say it's a feature 😄
I suggest instead of using NotificationCenter, to instead set a Bool, tableViewNeedsUpdate, and check for the value of that Bool when the view with the UITableView is presented, and the UITableView is visible and able to accept reloadData() calls. After the reload is complete, set the variable back to false.
I have looked at another question that was asking the exact same question as mine, but the answer told them to call the setEditing function (which I tried, and say later in the question). But I don't see how you could call this function only when the edit button is clicked. I suppose I could create my own BarButtonItem and run this method when my bar button item is clicked, but I figured this would be far easier since I need the basic functionality of the edit button.
I have a UIViewController that has a table on it named peersTable. When I click the edit button it switches to done, but nothing happens on the table. I have also added my own UITableViewRowActions and when I swipe to the left on the cells, my custom actions do show up.
Here is some of my code:
class PeerViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, ConnectionManagerDelegate {
#IBOutlet weak var peersTable: UITableView!
...
override func viewDidLoad() {
...
peersTable.delegate = self
peersTable.dataSource = self
self.navigationItem.rightBarButtonItem = self.editButtonItem
...
}
I have also tried calling the peersTable.setEditing(true, animated: true) method myself, and in this case, the red minus does appear. I've never seen this issue before, so I don't understand why it's happening. Am I somehow setting the delegate wrong? Or possibly I'm doing something wrong since this is a regular View and not a TableView (even though I've done this before in a previous project).
Thanks in advance! If you need any more information let me know!
Since this is a not a TableViewController it won't automatically set your tableView to editing mode when you press the edit button.
You need to override setEditing method so you can set the tableView to editing mode.
Add this to your ViewController class:
override func setEditing(_ editing: Bool, animated: Bool) {
super.setEditing(editing, animated: animated)
peersTable.setEditing(editing, animated: animated)
}
I'm trying to pass a trigger between 2 view controller but i can't find something that works ...
I have the main controller with a NSTableView, source linked, View Base.
main Controller class :
class ViewController: NSViewController {
I have an array defined in Global variables.
on the viewDidLoad i add 2 elements in my array, then i use setDelegate and setDataSource.
It works fine.
myLib.myCoins = fillCoinsTable()
print ("My lib has \(myLib.myCoins.count) objects ")
mainCoinTable.setDelegate(self)
mainCoinTable.setDataSource(self)
I have a segue from the WINDOWS CONTROLLER to my second view Controller.
(It's a ToolBar button). The segue is "Sheet" kind.
This second controller allows me to add an element in my global variable arrays, with a button "Save" .
Code on the second controller
#IBAction func addCoinButton(sender: AnyObject) {
//We add the coin
let newCoin:coin = coin(n: textName.stringValue)
newCoin.Year = Int.init(textYear.stringValue)
myLib.myCoins.append(newCoin)
self.dismissController(self)
}
If i add a button on the main controller, to reloadData on the TableView, it works fine. The third element is added.
but i would like that to be automatic ....
I tried segue, but mine is not between view controller but with the windows controller.
Can you please help ?
Thanks,
Nicolas
I think, you want to add data from oneViewController and without pressing button, you want after navigation or pressing back button, you want to reload automatically tableview to show updated results, right.
If I'm not wrong then, this solution will work for you.
Follow this below steps:
Step 1 :
Add this code in your view controller, from which you want to add data in array or in database, instead of button click.
override func viewDidLoad()
{
super.viewDidLoad()
let backItem = UIBarButtonItem(title: "Back", style: .Plain, target: self, action: "goBack")
self.navigationItem.leftBarButtonItem = backItem
}
func goBack()
{
NSNotificationCenter.defaultCenter().postNotificationName("load", object: nil)
self.navigationController?.popViewControllerAnimated(true)
}
Step 2:
Now its final step.
Now add this below code, to your result view controller, where you want to automatically update the result.
func loadList(notification: NSNotification){
self.TableView.reloadData()
}
override func viewWillAppear(animated: Bool) {
NSNotificationCenter.defaultCenter().addObserver(self, selector: "loadList:",name:"load", object: nil)
}
Now implement this code-stuff in your coding. Hope it works for you.
If you want the table to reload automatically when the View appears add this to viewWillAppear
self.tableView.performSelectorOnMainThread(#selector(UITableView.reloadData), withObject: nil, waitUntilDone: true)
In my UIViewController, I have an UITableView which contains different cells with saved contents by using the NSUserDefaults. I also have a custom UIBarButtonItem which causes the UITableView to enter and leave editing mode.
This all works, but the problem is when I tap the round red button and on the right side of the cell appears the delete button, the delete button doesn't work... I can tap on it as much as I want but the cell does not get deleted.
#IBAction func EditListButton(sender: UIBarButtonItem) {
if ShoppingListTable.editing {
ShoppingListTable.setEditing(false, animated: true)
self.EditListButton.title = "Edit"
} else {
ShoppingListTable.setEditing(true, animated: true)
self.EditListButton.title = "Done"
}
}
Use UITableViewDataSource's tableView:commitEditingStyle:forRowAtIndexPath: to detect a tap on the delete button.
Then in the implementation delete the row from your data source (NSUserDefaults in your case).
So in your tableView's dataSource (ie. in the class you implemented numberOfSectionsInTableView: for example), add your custom implementation of tableView:commitEditingStyle:forRowAtIndexPath: where you delete the underlying data.
I have a bit of an odd problem. Note that everything is done programmatically, so please no storyboard suggestions. Here's the setup:
I have a Master-Detail view layout, where the Detail view is a map. The Master-view's table is filled with cells that represent annotation points on the map. When you tap on a cell, it focuses on that annotation on the map and opens a custom annotation view using a popover. Likewise, when you tap the annotation itself, the same popover opens. So far, so good.
Now, inside the popover and inside each cell there is an a button which, when pressed, should open a new view that fills the whole screen. The view would have information specific to its corresponding annotation.
Here is how I am trying to do it:
Class that has the map (MyDetailViewController)
public func openNewViewController(){
self.presentViewController(NewViewController(), animated: true, completion: nil)
}
Function call for cell button and popover button
func btnPressed(sender: AnyObject){
var dvc = MyDetailViewController()
dvc.openNewViewController()
}
When either button gets tapped, I get the same error:
Warning: Attempt to present NewViewController on DetailViewController whose view is not in the window hierarchy!
So, what does it mean that DetailViewController is not in the window hierarchy..? It must be since I see it, no?
Any idea how to fix this issue? Thanks in advance!
Your function openNewViewController() is doing nothing!
See the code
self.presentViewController(openNewViewController()) , animated : true , completion: nil)
is pointing to itself.
Instead try this :
public func openNewViewController(){
var newController = UIViewController() // or any other view you wish to instantiate
self.presentViewController(newController, animated: true, completion: nil)
}