In my project there is a Segue Show(e.g. Push). After clicking the mainButton, TabBarController is presented. When I choose the second tab, the method setButtonsTitle is called and when I swipe the TabBarController down, I can see "item 2" instead of the "Button" title (default title). But when I click the first tab afterwards and swipe the TabBarController down, it remains "Button". My first thought was that the method does not get called, but this is not true (checked in debugger). Also, print(title) shows "Item 1".
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var mainButton: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let destination = segue.destination as! TabBarController
destination.selectionDelegate = self
}
}
extension ViewController : ButtonThings {
func setButtonsTitle(title: String){
mainButton.titleLabel?.text = title
print(title)
}
}
And the TabBarController:
import UIKit
class TabBarController: UITabBarController {
weak var selectionDelegate: ButtonThings?
override func viewDidLoad() {
super.viewDidLoad()
}
//MARK: UITabBarController
override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
selectionDelegate?.setButtonsTitle(title: item.title ?? "no title")
}
}
protocol ButtonThings : class {
func setButtonsTitle(title: String)
}
I was able to reproduce that issue that you had mentioned. I then set the button type to custom and the button title started showing correctly.
Hope this helps.
I am new to swift. I am implementing tabbar controller in my Project and facing some design difficulty. My goal is when user click a tabbar item it should not navigate to another view controller. It should stayed in the current view and add a pop up view to the current view controller.I have tried but always it navigate to next view controller.
Create a UITabBarController subclass and use that class for your tab bar controller. Confirm to UITabBarControllerDelegate in the tab bar controller and return false in tabBarController shouldSelect method when you don't want to navigate to a view controller. Here you can show the popup view.
class TabbarController: UITabBarController, UITabBarControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
delegate = self
}
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
if let navigationController = viewController as? UINavigationController,
navigationController.viewControllers.contains(where: { $0 is MoreViewController }) {
//show pop up view
return false
} else {
return true
}
}
}
Or you can add UITabBarControllerDelegate in one of its embedded view controller like this
class ViewController: UIViewController, UITabBarControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
self.tabBarController?.delegate = self
}
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
if let navigationController = viewController as? UINavigationController,
navigationController.viewControllers.contains(where: { $0 is MoreViewController }) {
//show pop up view
return false
} else {
return true
}
}
}
I want to make something like below snapshots.
When I click on profile tab bar instead of opening a new view controller it shows a side menu. Is it something that has been handled on click of tabbar ?
if you want to achieve something like your screenShot then you are using a wrong library, because when you show your right viewController the front viewController go to left by amount of width of your right viewController, but anyways here is the code for what you need to do
first you need to put your viewController as delegate of your TabBarViewController and in func tabBarController(tabBarController: UITabBarController, shouldSelectViewController viewController: UIViewController) -> Bool you need to return false and call the method of SWRevealViewController to show right viewController rightRevealToggleAnimated(true)
class FirstViewController: UIViewController,SWRevealViewControllerDelegate,UITabBarControllerDelegate {
#IBOutlet weak var sliderControl: UISlider!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.revealViewController().delegate = self
self.tabBarController?.delegate = self
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
//self.view.removeGestureRecognizer(self.revealViewController().panGestureRecognizer())
//self.view.addGestureRecognizer(self.revealViewController().panGestureRecognizer())
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func tabBarController(tabBarController: UITabBarController, shouldSelectViewController viewController: UIViewController) -> Bool {
//checking for specific viewController
if(viewController is DesiredViewControllerClass) {
self.revealViewController().rightRevealToggleAnimated(true)
}
return false
}
}
I hope this helps you, regards
You can use the tab bar delegate:
extension ViewController: UITabBarDelegate {
func tabBar(tabBar: UITabBar, didSelectItem item: UITabBarItem) {
// Present hamburger menu
}
}
I'm fairly new at iOS programming. I have this setup:
ViewController view on IB, with class ViewController
SecondController view on IB, with class secondController
I have protocol:
protocol SecondControllerDelegate {
func getSomething() -> String
}
and I have delegate variable on SecondController:
class secondController: UIViewController {
var delegate: SecondControllerDelegate?
#IBOutlet weak var labelStatus: UILabel!
override func ViewDidLoad() {
super.viewDidLoad()
}
#IBAction func buttonTouch(sender: AnyObject) {
labelStatus.text = delegate?.getSomething()
}
func try () {
labelStatus.text = "testing"
}
}
Now, according to the hints everywhere, in order so I can call delegate?.getSomething() at SecondController.buttonTouch(), I need to set like this on viewController:
class ViewController: UIViewController, SecondControllerDelegate {
override func viewDidLoad () {
super.viewDidLoad()
SecondController.delegate = self
}
func doSomething () -> String {
return "testing"
}
}
But this generates error 'SecondController.type' does not have a member named 'delegate'.
Some other websites say:
class ViewController: UIViewController, SecondControllerDelegate {
var secondController = SecondController()
override func viewDidLoad () {
super.viewDidLoad()
secondController.delegate = self
}
func doSomething () -> String {
return "testing"
}
}
With this, there are no error. But if I do something on the second screen that should call the delegate, it doesn't call the delegate, like the SecondController is two different objects (one is created by StoryBoard, one is created manually within the ViewController), i.e. the labelStatus that should have changed to "testing", doesn't change at all. But it changes if function try() is called. How am I supposed to do this?
EDIT: I forgot to mention that I used NavigationController, and segue to transition from first screen to second screen.
Because you try to learn how to build a delegate in Swift, I have written you a plain delegate example below
protocol SecondViewControllerDelegate {
func didReceiveInformationFromSecondViewcontroller (information: String)
}
class ViewController: UIViewController, SecondViewControllerDelegate {
func openSecondViewController () {
if let secondViewControllerInstance: SecondViewController = storyboard?.instantiateViewControllerWithIdentifier("SecondViewController") as? SecondViewController {
secondViewControllerInstance.delegate = self
navigationController?.pushViewController(secondViewControllerInstance, animated: true)
}
}
func didReceiveInformationFromSecondViewcontroller(information: String) {
////Here you get the information, after sendInfoToViewController() has been executed
}
}
class SecondViewController: UIViewController {
var delegate: SecondViewControllerDelegate?
func sendInfoToViewController () {
delegate?.didReceiveInformationFromSecondViewcontroller("This ist the information")
}
}
UPDATE
Following the same thing in using Storyboard Segues
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let secondViewControllerInstance: SecondViewController = segue.destinationViewController as? SecondViewController {
secondViewControllerInstance.delegate = self
}
}
I've been having some trouble with something I thought might be easy. I have a table in my root view controller, when a row is selected I push a new view and from there I go to another tab.
My question is how do I make sure that as soon as the user taps the first tab the navigation controller will pop to root?
Following delegate is called while each tab is selected on tabbar.
-(void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
Put following code inside this delegate method.
if ([viewController isKindOfClass:[UINavigationController class]])
{
[(UINavigationController *)viewController popToRootViewControllerAnimated:NO];
}
its working fine on my app.
For Swift lovers:
import UIKit
class YourTabBarControllerHere: UITabBarController,
UITabBarControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
self.delegate = self;
}
func tabBarController(tabBarController: UITabBarController,
didSelectViewController viewController: UIViewController) {
if let vc = viewController as? UINavigationController {
vc.popViewControllerAnimated(animated: false);
}
}
}
Edit: Swift 3 update, thanks to #Justin Oroz for pointing that out.
In Swift 3.1
Add UITabBarControllerDelegate to your TabBar Class:
class YourClass: UITabBarController, UITabBarControllerDelegate {
After:
override func tabBar(tabBar: UITabBar, didSelectItem item:
UITabBarItem) {
let yourView = self.viewControllers![self.selectedIndex] as! UINavigationController
yourView .popToRootViewControllerAnimated(false)
}
What you are trying to do sounds a little bit odd. Have you read the Human Interface Guidelines on combining UINavigationControllers and UITabBarControllers?
However, what you need to do is detect the selection of the tab by setting a delegate for your UITabBarController and implementing the tabBarController:didSelectViewController: delegate method. In this method you need to pop back to the root view controller using UINavigationController's popToRootViewControllerAnimated: method.
Swift 5.1 Answer:
class YourTabBarName: UITabBarController, UITabBarControllerDelegate
{
override func viewDidLoad()
{
super.viewDidLoad()
self.delegate = self
}
func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController)
{
if let vc = viewController as? UINavigationController
{ vc.popToRootViewController(animated: false) }
}
}
[self.navigationController popToRootViewControllerAnimated:NO];
Swift 4.2
The solution that works for me is to subclass the UITabBarController and add the two delegate functions as follows:
import UIKit
class MyCustomTabBarController: UITabBarController, UITabBarControllerDelegate {
var previousSelectedTabIndex:Int = 0
override func viewDidLoad() {
super.viewDidLoad()
self.delegate = self
}
func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
self.previousSelectedTabIndex = tabBarController.selectedIndex
}
override func tabBar(_ tabBar: UITabBar, didSelect item:
UITabBarItem) {
let vc = self.viewControllers![previousSelectedTabIndex] as! UINavigationController
vc.popToRootViewController(animated: false)
}
}
Make sure you set animated to false otherwise you will get
Unbalanced calls to begin/end appearance transitions for the targeted ViewController
Try this.
class TabBarClass: UITabBarController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
let vc = self.viewControllers![selectedIndex] as! UINavigationController
vc.popToRootViewController(animated: false)
}
}
First, you should create subclass of UITabbarController and add Observer:
- (void)viewDidLoad {
[super viewDidLoad];
[self.tabBar addObserver:self forKeyPath:#"selectedItem" options:NSKeyValueObservingOptionOld | NSKeyValueObservingOptionNew context:nil];
}
When tabbar is selected, We will process in method:
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context{
if ([keyPath isEqualToString:#"selectedItem"] && [object isKindOfClass:[UITabBar class]]){
UITabBar *bar = (UITabBar *)object; // The object will be the bar we're observing.
// The change dictionary will contain the previous tabBarItem for the "old" key.
UITabBarItem *wasItem = [change objectForKey:NSKeyValueChangeOldKey];
NSUInteger was = [bar.items indexOfObject:wasItem];
// The same is true for the new tabBarItem but it will be under the "new" key.
UITabBarItem *isItem = [change objectForKey:NSKeyValueChangeNewKey];
NSUInteger is = [bar.items indexOfObject:isItem];
if (is == was) {
UIViewController *vc = self.viewControllers[is];
if ([vc isKindOfClass:[UINavigationController class]]) {
[(UINavigationController *)vc popToRootViewControllerAnimated:YES];
}
}
}
}
The UTabController suggests a different UX for letting a user "pop to root". When switching back to a tab, it keeps the full UINav stack from before. If they tap the bar item a second time (tapping the selected tab), only then does it pop to root. That's all automatic. Some apps, like instagram, allow a third tap to scroll to top.
I'd suggest sticking with the defaults as that's what users will be expecting.
The below had worked for me .This code in swift 3:
1> subclass UITabbarController and implement two below method with one iVAr:
class MyTabBarController: UITabBarController ,UITabBarControllerDelegate {
var previousSelectedTabIndex : Int = -1
}
2> set the tabbar delegate in viewdidLoad
override func viewDidLoad() {
super.viewDidLoad()
self.delegate = self // you must do it}
func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
self.previousSelectedTabIndex = tabBarController.selectedIndex
}
func tabBarController(_ tabBarController: UITabBarController,
shouldSelect viewController: UIViewController) -> Bool {
if self.previousSelectedTabIndex == tabBarController.selectedIndex {
let nav = viewController as! UINavigationController // mine in nav_VC
for vc in nav.childViewControllers {
if vc is YUOR_DESIRED_VIEW_CONTROLLER {
nav.popToViewController(vc, animated: true)
return false// IT WONT LET YOU GO TO delegate METHOD
}
}
}
return true
}
tabBarController.selectedIndex give you the selected tab
In tabBarController_shouldSelect_viewController method you can set your desired view controller with some easy calculation.
if you are not getting the above code play with both above method and you come to know how both working together
Use selected view controller to popToRootViewController. Basically you need to cast this instance.
Swift
((selectedViewController) as! UINavigationController).popToRootViewController(animated: false)
//
// I just added extra line so the scroll bar won't annoy you.
Xcode 11.5, Swift 5:
You don't need to use two delegate methods. Only one is enough:
extension CustomTabBarController: UITabBarControllerDelegate {
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
if tabBarController.viewControllers?.firstIndex(of: viewController) == tabBarController.selectedIndex,
let navigationController = viewController as? UINavigationController {
navigationController.popToRootViewController(animated: true)
}
return true
}
}
//create a tabbar controller class set it to your TabbarController in storyboard
import UIKit
class MyTabbarViewController: UITabBarController,UITabBarControllerDelegate{
override func viewDidLoad() {
super.viewDidLoad()
self.delegate = self
}
func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController)
{
if let vc = viewController as? UINavigationController
{ vc.popToRootViewController(animated: false) }
}
}