Which Controller was before? - ios

I got TabBar Application with 3 ViewControllers.
Can i know from the ViewControllers's method which ViewContoller was desplayed before (1 or 2)? Or maybe i open VeiwController from some other .xib

You can do this by implementing UITabBarController delegate method -
- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController
{
}
in this you can check for [tabBarController selectedViewController] , here selectedViewController is the view controller which is currently selected and viewController is which is going to be selected.

I just creating #property in target VeiwController and set this #property firstly in viewDidLoad. So i know that firstly this ViewController will appear from TabBar. After that i can change it in some other ViewController's methods, which call some subviews (.xib).

Related

want to call myMethod() when selecting same tab bar in IOS

I Want to call my own method, i.e. myMethod() when same tab bar is selected which is already selected.
I had tried to call didSelectMethod() but it is not called in my ViewController class.
Please help me in this,
Thank you
Jagveer Rana
Where you own your tabBarController instance there you set delegate
tabBarController.delegate= self; // It is must to set delegate
add the below delegate method
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
if ([viewController respondsToSelector:#selector(myMethod)]) {
[viewController performSelector:#selector(myMethod)];
}
}
It sounds like your ViewController class is not the delegate for your UITabBarController, otherwise tabBarController:didSelectViewController: would be called.
Make sure your delegate is linked up properly.
If that's not the problem, then there are a few other StackOverflow questions asking the same thing:
Tab bar, reload every time tab is pressed
Detect a re-tab on selected UITabbarItem

Checking when a TabBar item is clicked - Objective C

I have a ViewController with 2 sub containers. The first sub container points to a ViewController with a TabBar inside it. The second sub container is a ViewController that contains a collection view. Now my issue is trying to access the first sub containers TabBar so that when an Item is clicked, I can know which item is clicked and process my data.
The main ViewController has a class. All the other sub containers for that ViewController also have a class. Here is the .h for my sub container with the Tab Bar:
#import <UIKit/UIKit.h>
#interface home_tab : UIViewController <UITabBarControllerDelegate>{
}
#end
.m:
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
-(void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
NSLog(#"working");
}
Now when clicking on the Tab Bar that is populated, didSelectViewController is never called.
I am using storyboard.
Suggestions and thoughts?
Try this on your viewDidLoad
- (void)viewDidLoad
{
[super viewDidLoad];
[[self tabBarController]setDelegate:self];
// Do any additional setup after loading the view, typically from a nib.
}
It's just an suggestion :)
[[self tabBarController]selectedIndex] This will return the index of the selected tab.
I think you have a couple problems atleast from what I can see here,
You are using a TabBar inside of a ViewController, not a UITabBarController, thus you need to use UITabBarDelegate not UITabBarControllerDelegate. You will have to manage the view controllers or whatever view you will want to be loaded on your own most likely with the delegate callback:
-(void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item;
Also you dont have a UITabBar defined in your controller, therefore your ViewController has no idea you have a UITabBar in your Storyboard. You need something like this:
#interface ViewController : UIViewController <UITabBarDelegate>
#property (weak, nonatomic) IBOutlet UITabBar *tabBar;
#end
Then you will need to Control drag from the ViewController to your UITabBar and back to connect the Delegate in your Storyboard.
Id recommend using a UITabBarController so you dont have to manage the views yourself depending on what you are trying to accomplish.
Hope this helps!
the didSelectViewController method is part of the UITabBarControllerDelegate Protocol and is called on the UITabBarController's delegate. Did you set the delegate of the tab bar controller to the current instance of your subcontainer? Inside ViewDidLoad: do something like this:
[self.tabBarController setDelegate:self];
You can also set a delegate on the UITabBar rather than the controller, and the UITabBarDelegate Protocol contains a method tabBar:didSelectItem: that would be called.

Subclass UITabBarController in iOS6 with storyboards

I started a new project with iOS 6 ARC and Storyboards
I made a very simple app that has a Tabbar and 2 views
so now I created a TestViewController file with is extending UITabBarController and I put the custom class in the storyboard.
now the issue is that I am trying to implement some delegate methods like
- (BOOL) tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController;
But it never calls it. Can anyone help?
I noticed too that if I put that code in the first view controller it works fine. It seems like the first view controller overwrites the TabBarController before. I am very confused.
for more testing I added in the TestViewController.m some logging:
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
NSLog(#"%#",self.tabBarController.viewControllers);
}
and the view controllers are null.
I even tried doing self.tabBarController.delegate = self;
But still no solution.
TestViewController is your tab bar controller, so your log should just be self.viewControllers, not self.tabBarController.viewControllers. You shouldn't need to add the property viewControllers either, since your subclass inherits that property from UITabBarController. The reason your delegate message is not called is because of the same problem. You should set the delegate with (in TestViewController):
self.delegate = self;
This is assuming that you want TestViewController to be the delegate, it wasn't clear to me if that's what you wanted.
Have you tried linking them in Interface Builder?
Add this to your header file first though
#property (nonatomic, retain) IBOutlet UITabBarController *tabBarController;

didSelectViewController method not being called (with storyboard)

I have 2 versions of a tabbed ios5 application, one created using a storyboard and one using xib files. The storyboard version does not call the UITabBarControllerDelegate method didSelectViewController (the xib version does). Something is (I think) missing from the storyboard, but I don't know what. Another way of framing the question might be — how can I refer to the UITabBarController object instantiated by the storyboard?
Thanks for your help.
EDIT: The tab bar controller delegate is set:
In AppDelegate.h:
#interface MyAppDelegate : UIResponder <UIApplicationDelegate, UITabBarControllerDelegate>
#property (strong, nonatomic) UITabBarController *tabBarController;
In AppDelegate.m:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.tabBarController.delegate = self;
return YES;
}
Then later in AppDelegate.m, the delegate method is:
- (void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
NSLog(#"Got Here");
}
The NSLog output never appears. The problem seems to me to be that I am not correctly referencing the tab bar controller object which has been instantiated by the storyboard.
How do I do that?
I had this issue.
If you're not using storyboards, setting the UITabBarController delegate in the AppDelegate is the way to go. However, with Storyboards, the AppDelegate has no idea where the tabBarController is on startup. You'd think by subclassing the tabBarController and adding the delegate method:
(void)tabBarController:(UITabBarController *)tabBarController
didSelectViewController:(UIViewController *)viewController {
}
... would be enough. But, it's irritatingly not.
I needed to know when a user had pressed a tab button. I needed to know this more that I needed to know that the viewController's "- (void)viewWillDisappear:(BOOL)animated {}
" method had been run.
I decided to make my UITabBarController a delegate of itself. This seemed silly to me but I did the following...
#import <UIKit/UIKit.h>
#interface PlumbsTabBarController : UITabBarController <UITabBarControllerDelegate>
#end
And then, in my viewDidLoad method, wrote the following:
[self setDelegate:self];
Which enabled my tab bar delegate methods to run.
Crazy or what?
Ok - I'm editing this answer now, as even though the above is all correct, where a navigationController is being used, selected with each tabBarButton touched, the didSelectViewController delegate method will, when you try to NSLog(#"%#", viewController); only show you that you have selected the UINavigationController class?
So, the total solution, just to add more complexity, is to subclass the UINavigationController for each viewController that you want to monitor, (do something) when the tabBarbutton has been touched.
It works for me anyhow. And, if anyone can nit-pick through the above dribble, they might find an aspect that's useful - and that's enough for me - seeing as I find this site utterly useful too.
Put [self setDelegate:self]; in your ViewDidLoad or somewhere where the object get's initialized

How do I know when a tab bar item is pressed (iOS)

I have 2 view controllers and a tab bar controller created in storyboard.
is it possible to execute a method in either of the 2 view controllers when the relevant tab bar is pressed?
Ive tried several ways but they need a nib name on the firstViewController or secondViewController if I want to initialize an object of the firstViewController, normally the firstViewController is just created on launch,
Any help would be appreciated, I'm vaguely familiar with the uitabcontroller app delegate but I don't know how to hook up the two view controllers to the tab controller
Have a look at the UITabViewController Delegate :
You use the UITabBarControllerDelegate protocol when you want to
augment the behavior of a tab bar. In particular, you can use it to
determine whether specific tabs should be selected, to perform actions
after a tab is selected, or to perform actions before or after the
user customizes the order of the tabs. After implementing these
methods in your custom object, you should then assign that object to
the delegate property of the corresponding UITabBarController object.
All of the methods in this protocol are optional.
Reference : http://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/UITabBarControllerDelegate_Protocol/Reference/Reference.html
What you need should be achievable by implementing :
- (void)tabBarController:(UITabBarController *)tabBarController
didSelectViewController:(UIViewController *)viewController
If you are using storyboard, do this
in didFinishLaunchingWithOptions
UITabBarController *tabBar = (UITabBarController *)self.window.rootViewController;
[tabBar setDelegate:self];
And then
-(void) tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
//Write your code here
}

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