How can i detect the end of scrollToRow function in my tableview? i have tried to implement scrollViewDidEndScrollingAnimation function, however it doesn't get called when end of scrollToRow.
You should add the delegate to your Scrollview:
override func viewDidLoad()
{
super.viewDidLoad()
self.scrollview.delegate = self
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let height = scrollView.frame.size.height
let contentYoffset = scrollView.contentOffset.y
let distanceFromBottom = scrollView.contentSize.height - contentYoffset
if distanceFromBottom < height {
print(" you reached end of the table")
}
}
Related
I have a problem showing a tabbarVC.
Here is the codes:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
let tabBarVC = UITabBarController()
guard let vc1 = storyboard?.instantiateViewController(identifier: "FirstController") as? FirstController else {
print("failed to get vc1 from Storyboard")
return
}
guard let vc2 = storyboard?.instantiateViewController(identifier: "SecondController") as? SecondController else {
print("failed to get vc2 from Storyboard")
return
}
guard let vc3 = storyboard?.instantiateViewController(identifier: "ThirdController") as? ThirdController else {
print("failed to get vc3 from Storyboard")
return
}
let vc4 = UINavigationController(rootViewController: vc1)
let vc5 = UINavigationController(rootViewController: vc2)
let vc6 = UINavigationController(rootViewController: vc3)
vc4.title = "XXX"
vc5.title = "YYY"
vc6.title = "ZZZ"
tabBarVC.setViewControllers([vc4,vc5,vc6], animated: false)
tabBarVC.modalPresentationStyle = .fullScreen
self.present(tabBarVC, animated: true)
}
}
The tabbar has shown correctly, but I got a warning of "Unbalanced calls to begin/end appearance transitions for <tabbarcontroltest.ViewController:" which I don't understand.
Also I have tried to change
tabBarVC.modalPresentationStyle = .fullScreen
to
tabBarVC.modalPresentationStyle = .overFullScreen
And, then I don't have this warning, but instead, when I try to close the app by home button,
I got another warning as
tabbarcontroltest[Presentation] Attempt to present on <tabbarcontroltest.ViewController> (from <tabbarcontroltest.ViewController) which is already presenting .
I guess there is something wrong with the presentation style? Or is there something else wrong?
Thanks
found the solution by myself. the correct way is as follows:
tabBarVC.modalPresentationStyle = .fullScreen
tabBarVC.view.frame = self.view.bounds
addChild(tabBarVC)
view.addSubview(tabBarVC.view)
tabBarVC.willMove(toParent: self)
I want to add a new To Do item when i press the add button,but i don't want to switch to another page.
press the add button to add a new row in the table view,input something and press the done button,it will save.
somebody suggests me to save the cells data to Model,but i don't know how to write this.
Who can help me?
import UIKit
import CoreData
class ToDoViewController: UIViewController {
var items: [NSManagedObject] = []
#IBOutlet weak var tableView: UITableView!
#IBAction func addItem(_ sender: UIBarButtonItem) {
//***How to write this code***
}
#IBAction func done(_ sender: UIBarButtonItem) {
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
return
}
let managedContext = appDelegate.persistentContainer.viewContext
let entity = NSEntityDescription.entity(forEntityName: "ToDo", in: managedContext)!
let item = NSManagedObject(entity: entity, insertInto: managedContext)
//***let list = the current textView's text
//how to get the textView's text and assign it to a value.***
item.setValue(list, forKeyPath: "summary")
do {
try managedContext.save()
items.append(item)
} catch let error as NSError {
print("Could not save.\(error),\(error.userInfo)")
}
}
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(UITableViewCell.self,forCellReuseIdentifier: "Cell")
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
return
}
let managedContext = appDelegate.persistentContainer.viewContext
let fetchRequest = NSFetchRequest<NSManagedObject>(entityName: "ToDo")
do {
items = try managedContext.fetch(fetchRequest)
} catch let error as NSError {
print("Could not fetch.\(error),\(error.userInfo)")
}
}
}
extension ToDoViewController: UITableViewDataSource{
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let item = items[indexPath.row]
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
let textView = UITextView(frame: CGRect(x: 0, y: 0, width: cell.frame.size.width, height: cell.frame.size.height))
cell.addSubview(textView)
textView.text = item.value(forKey: "summary") as? String
return cell
}
}
Ok so If my understanding is right you need a new row to be added if they create a new entry into your Core Data. So in your viewWillAppear you're doing a fetch. What I think you need is a:
var fetchResultController : NSFetchedResultsController<YourType>!
Then using this fetch controller you want to do the following when fetching:
private func GetToDoEntries(){
if let appDele = UIApplication.shared.deletgate as? AppDelegate{
let givenContext = appDele.persistantContainer.viewContex
let entryFetchRequest : NSFetchRequest<YourType> = YourType.fetchRequest()
let sortDescriptors = NSSortDescriptor(key: "yourEntrySortKey" , ascending: true)
entryFetchRequest.sortDescriptors = [sortDescriptors]
fetchResultController = NSFetchedResultsController(fetchRequest: entryFetchRequest, managedObjectContext: givenContext, sectionNameKeyPath: nil, cacheName: nil)
fetchResultController.delegate = self
do{
//Gets fetched data based on our criteria
try fetchResultController.performFetch()
if let fetchedEntries = fetchResultController.fetchedObjects{
items = fetchedEntries as? WhateverToCastTo
}
}catch{
print("Error when trying to find entries")
}
}
}
First I'm sorry but I've just written this here is stackOverflow. So what you're doing is using a fetch result controller instead of a traditional search. You are required to have the sort descriptor as well and you can try to get the results and cast them to your items or as a NSManagedObject.
Now we're not done though. Your script needs to inherit from some behaviour. At the top of your class
class ToDoViewController : UIViewController, NSFetchedResultsControllerDelegate
You need the delegate as you can see in the first block of code because we're assigning it. Now we're almost there. You just need some methods to update the table for you and these come with the delegate we just inherited from.
//Allows the fetch controller to update
func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
tableView.beginUpdates()
}
//Allows new additions to be added to the table
func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
switch type{
case .insert:
if let _newIndexPath = newIndexPath{
tableView.insertRows(at: [_newIndexPath], with: .fade)
}
case .update:
if let index = indexPath{
tableView.reloadRows(at: [index], with: .fade)
}
default:
budgetEntryTable.reloadData()
}
if let fetchedObjects = controller.fetchedObjects{
items = fetchedObjects as! [NSManagedObject (Or your cast type)]
budgetEntryTable.reloadData()
}
}
//Ends the table adding
func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
tableView.endUpdates()
}
So there are 3 methods here. The first and second are very self explanatory. They begin and end the updates on your tableView. I'd also recommend that you change the name of your tableView to something other than "tableView" just for clarity.
The method in the middle uses a switch. My example is missing the "Move" and "Delete" options as I didn't required them in my project but you can add them to the switch statement.
The insert is checking the newIndexPath to see if there is one. If so then we add an array of the amount of rows required at the newIndexPath.
The update just checks the current index paths and then reloads the data on them incase you updated your data model.
I hope this is what you were looking for. Good luck! I'll try and help more if you need it but that should get you started.
Having problem in displaying polyline on the mapview
Following this tutorial
MapView Tutorial
Attached is my code.
Annotation is appearing on the map but unable to call the renderer method. Though the delegate is there.
Main Problem: Unable to draw line between two coordinates
Console Output: 2017-02-06 22:54:56.770584 MapTest[2329:805733] [LogMessageLogging] 6.1 Unable to retrieve CarrierName. CTError: domain-2, code-5, errStr:((os/kern) failure)
Here is the code
import UIKit
import MapKit
class ViewController: UIViewController,MKMapViewDelegate {
#IBOutlet weak var myMap: MKMapView!
override func viewDidLoad() {
super.viewDidLoad()
// 1.
myMap.delegate = self
// 2.
let sourceLocation = CLLocationCoordinate2D(latitude: 40.759011, longitude: -73.984472)
let destinationLocation = CLLocationCoordinate2D(latitude: 40.748441, longitude: -73.985564)
// 3.
let sourcePlacemark = MKPlacemark(coordinate: sourceLocation, addressDictionary: nil)
let destinationPlacemark = MKPlacemark(coordinate: destinationLocation, addressDictionary: nil)
// 4.
let sourceMapItem = MKMapItem(placemark: sourcePlacemark)
let destinationMapItem = MKMapItem(placemark: destinationPlacemark)
// 5.
let sourceAnnotation = MKPointAnnotation()
sourceAnnotation.title = "Times Square"
if let location = sourcePlacemark.location {
sourceAnnotation.coordinate = location.coordinate
}
let destinationAnnotation = MKPointAnnotation()
destinationAnnotation.title = "Empire State Building"
if let location = destinationPlacemark.location {
destinationAnnotation.coordinate = location.coordinate
}
// 6.
self.myMap.showAnnotations([sourceAnnotation,destinationAnnotation], animated: true )
// 7.
let directionRequest = MKDirectionsRequest()
directionRequest.source = sourceMapItem
directionRequest.destination = destinationMapItem
directionRequest.transportType = .automobile
// Calculate the direction
let directions = MKDirections(request: directionRequest)
// 8.
directions.calculate {
(response, error) -> Void in
guard let response = response else {
if let error = error {
print("Error: \(error)")
}
return
}
let route = response.routes[0]
self.myMap.add((route.polyline), level: MKOverlayLevel.aboveRoads)
let rect = route.polyline.boundingMapRect
self.myMap.setRegion(MKCoordinateRegionForMapRect(rect), animated: true)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func mapView(mapView: MKMapView, rendererForOverlay overlay: MKOverlay) -> MKOverlayRenderer {
print("Line 85 is being called......start...")
let renderer = MKPolylineRenderer(overlay: overlay)
renderer.strokeColor = UIColor.red
renderer.lineWidth = 4.0
print("Line 85 is being called.......end..")
return renderer
}
}
Your rendererForOverlay function has the wrong syntax; Xcode told me this when testing your code. Use
func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer
Instead, and a line will be drawn between the two points.
I have a UISearchController inside of a UINavigationBar. The user has to tap on a UIBarButtonItem, in which I instantiate a new UIViewController then present it, in order to begin searching.
class ViewController: UIViewController {
var searchController: UISearchController!
override func viewDidLoad() {
super.viewDidLoad()
setupSearchController()
}
func setupSearchController() {
searchController = UISearchController(searchResultsController: nil)
searchController.searchBar.delegate = self
searchController.searchResultsUpdater = self
searchController.searchBar.showsCancelButton = true
searchController.dimsBackgroundDuringPresentation = false
searchController.hidesNavigationBarDuringPresentation = false
definesPresentationContext = true
navigationItem.titleView = searchController.searchBar
}
}
I've done plenty of research before hand, but still can't manage to find a solution...
Help in making the search controller become the first responder would be very much appreciated.
Making the UISearchBar the first responder on the main thread was the solution.
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
DispatchQueue.main.async {
self.searchController.searchBar.becomeFirstResponder()
}
}
So I'm trying to implement a custom animation as my app transitions from one View Controller to another, but for some reason the animateTransition function in my custom animation class is never called.
For the record, I'm using Xcode 8 and writing in Swift 3. The problem I'm trying to over come, is that the function is never called - I'll sort out the actual animation in the future, for now its
Here is the code in my CustomPresentAnimationController class, which should handle the transition animation...
import UIKit
class CustomPresentAnimationController: NSObject, UIViewControllerAnimatedTransitioning, UIViewControllerTransitioningDelegate, UINavigationControllerDelegate {
let duration = 0.5
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
print("Checking duration")
return duration
}
func animationController(forPresented presented: UIViewController, presentingController presenting: UIViewController, sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
print("This ran 1")
return self
}
func presentationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
print("This ran 2")
return self
}
func animationController(navigationController: UINavigationController, animationControllerForOperation operation: UINavigationControllerOperation, fromViewController fromVC: UIViewController, toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
print("This ran 3")
return self
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
print("It's working!")
guard let fromView = transitionContext.view(forKey: UITransitionContextViewKey.from) else {
return
}
guard let toView = transitionContext.view(forKey: UITransitionContextViewKey.to) else {
return
}
let container = transitionContext.containerView
let screenOffDown = CGAffineTransform(translationX: 0, y: -container.frame.height)
let screenOffUp = CGAffineTransform(translationX: 0, y: container.frame.height)
container.addSubview(fromView)
container.addSubview(toView)
toView.transform = screenOffUp
UIView.animate(withDuration: duration, delay: 0.0, usingSpringWithDamping: 0.8, initialSpringVelocity: 0.8, options: [], animations: {
fromView.transform = screenOffDown
fromView.alpha = 0.5
toView.transform = CGAffineTransform.identity
toView.alpha = 1
}) { (success) in
transitionContext.completeTransition(success)
}
}
}
Here is the code for my ViewController (which both of my View Controllers reference)...
import UIKit
class ViewController: UIViewController, UINavigationControllerDelegate, UIViewControllerTransitioningDelegate {
override func viewDidLoad() {
if transitioningDelegate != nil {
print("Should do something...")
print(transitioningDelegate)
} else {
print("Transitioing Delegate set to nil")
}
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.navigationController?.delegate = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
let customPresentAnimationController = CustomPresentAnimationController()
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
print("doing our custom transition")
print(segue.destination)
let destination = segue.destination
destination.transitioningDelegate = customPresentAnimationController
}
}
When I run the code, and click on the button I provided, which links to my seance View Controller, and is set to 'Present Modally', the view changes with the standard transition (slides up from the bottom) - and the following is printed out to Xcode:
Transitioing Delegate set to nil
doing our custom transition
<moduleView.ViewController: 0x7fe427f09a40>
Should do something...
Optional(<moduleView.CustomPresentAnimationController: 0x60800002e980>)
Obviously the first line is just as the first view loads, all the rest shows that my transitionDelegate is set on the Segue destination, and is indeed loaded in as the second view loads, and that the transitionDelegate is set to CustomPresentAnimationController... yet none of the functions in that class are ever called as it never prints anything out from those functions.
Any help appreciated!
Ensure the method signature for implementing the delegate matches the updated Swift 3 syntax.