I am assigning my view controller to my tab right after I create it. Is it possible to select the view that will show after the tab is clicked?
For eg
//user clicks tab 1
if(hasMessages)
//show view A
else
//show view B
Yes, it is possible. You need to set a delegate for your tab controller:
UITabBarController *tabBarController = (UITabBarController *)self.window.rootViewController;
tabBarController.delegate = self; // or whatever suitable class you have
This delegate needs to conform to the UITabBarControllerDelegate protocol.
In your delegate, implement tabBarController:didSelectViewController: and inside it, find out which view you want to present. Assuming your tab's root view controller is a navigation controller, then the delegate method implementation would be something like this:
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
/* logic goes here */
[viewController pushViewController:someNewVC animated:YES];
}
Related
I am having a problem with managing more than one UINavigationControlller.
I have a UITabBar and in every tab I have a separate UINavigationController. So If I switch in UITabBar by
tabBar.selectedIndex = i; // where i is index of tabbar.
and when I go back to previous tab by
tabBar.selectedIndex = previousIndex;
I go to the root of the UINavigationController, not the viewcontroller which I left previously.
I want to go to the viewcontroller from which I jump to another tab, without calling -viewDidLoad: or -viewWillAppear:.
I need a method which show either UINavigationController or my viewController.
The following method when implemented in your AppDelegate.m file will be fired whenever u try to switch the tabs
- (BOOL)tabBarController:(UITabBarController *)tbc shouldSelectViewController:(UIViewController *)viewController {
}
specify in your appDelegate class as the delagate of your tabbarcontroller
ie.( TabBarController.delegate = self) in appDidFinishLaunching method
I want to hide an image when the tabBar button is pressed.I have
self.tabBarController.delegate = self;
in my app delegate and the code below is located in my view controller's .m file . but it doesn't work . Can anyone help pls ?
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController{
if (viewController.tabBarController == nil)
{
img.hidden = YES;
NSLog(#"Tab Bar Button");
}
}
Do you know that
In versions of iOS prior to version
3.0, this method is called only when the selected view controller actually
changes. In other words, it is not
called when the same view controller
is selected.
In addition to this, make sure you are hiding the imageView that contains the image.
UPDATE
Get the tabBarController instance in the view controller and make its delegate the view controller. Then you can call this method in the view controller.
give name for the tabbarcontroller and then set the delegate for that.If my suggestion not useful,then ask me freely
I have a tabBarController that I add by placing the following code into:
AppDelegate.h:
...
UITabBarController IBOutlet *tabBarController;
}
#property (nonatomic, retain) IBOutlet UITabBarController *tabBarController;
AppDelegate.m:
...
[self.window addSubview:tabBarController.view];
[self.window makeKeyAndVisible];
[tabBarController setDelegate:self];
I then use the following code to present a modal barcode scanning View Controller:
- (void)tabBarController:(UITabBarController *)tbc didSelectViewController:(UIViewController *)vc {
// Middle tab bar item in question.
if (vc == [tabBarController.viewControllers objectAtIndex:2]) {
ScanVC *scanView = [[ScanVC alloc] initWithNibName:#"ScanViewController" bundle:nil];
// set properties of scanView's ivars, etc
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:scanView];
[tabBarController presentModalViewController:navigationController animated:YES];
[navigationController release];
[scanView release];
}
}
When it does actually get presented I think this method isn't visually appealing, because when I dismiss the modal view I am brought back to an empty view.
A lot of barcode scanning applications or applications that simply display an image picker for example; do this quite successfully. I'm just wondering what kind of implementation they would use in order to achieve such an effect.
This is a screenshot of an application called Path, which has the exact same functionality I'm after:
I also noticed that in these applications, if you are on any other tab bar item other than the middle one let's say, and you click on the tab bar item that presents the modal view, once it gets dismissed it doesn't actually bring them back to an empty view it dismisses like normal, however the actual tab bar item that presents the modal view is never selected. I would be happy with this type of functionality if that's the only way to implement this type of effect.
Any help would be greatly appreciated as I've been stuck in this for quite some time. Also I'm not even sure whether it's the right way to put all of this code in my AppDelegate in order for the View Controller to be presented as a modal. It all seems, just, wrong.
Not entirely what I'm after, but I think I can move forward from this:
http://idevrecipes.com/2010/12/16/raised-center-tab-bar-button/
When you dismiss the modal view controller, tell the tab bar to select whatever tab was originally selected.
- (void)dismissModalViewControllerAnimated:(BOOL)animated
{
// do whatever you need to do when dismissing
// savedTabIndex is an int ivar
// tabBarController is a reference, set when showing the modal view
[[self tabBarController] setSelectedIndex:savedTabIndex];
}
You would have to save the original tab bar selection in a variable at the start of tabBarController:didSelectViewController:.
- (void)tabBarController:(UITabBarController *)tbc
didSelectViewController:(UIViewController *)vc
{
// Save the tab bar index (if it's not the photo tab)
if ([tabBarController selectedIndex] != 3]) {
savedTabIndex = [tabBarController selectedIndex];
}
}
There could be mistakes in this code, I just typed it without testing.
I found a really easy solution by playing around UITabBarControllerDelegate--I only tried this in iOS 7 though.
First, subclass UITabBarController, make it its own UITabBarControllerDelegate, and create a property that'll hold a reference to the tab you want to launch a modal with. In my app, it's called the "Sell" tab.
#property (strong, nonatomic) UIViewController *sellTab;
Then, in your init method, just create that view controller and add it to the tabs.
_sellTab = [[UIViewController alloc] init];
_sellTab.title = #"Sell";
self.viewControllers = #[homeTab, historyTab, _sellTab, bookmarksTab, profileTab];
Now here's where the magic is: override the following tab bar controller delegate methods. Code is pretty self-explanatory.
#pragma mark - Tab bar controller delegate
- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController
{
return viewController != self.sellTab;
}
- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item
{
if (item == self.sellTab.tabBarItem) {
[self presentViewController:[[UINavigationController alloc] initWithRootViewController:[[PostAdViewController alloc] init]] animated:YES completion:nil];
}
}
This will launch a modal which, upon dismissal, shows the same tab you were in before launch.
You shouldn't present a modal view, when the user clicks on a tab bar item.
You could instead present a modal view from within a view that's presented by one of the tabs.
Or, if you just have a single main view and the scan view you want to present modally, you should just use a button to present the scan view from within your main view. You could for instance use a toolbar with a single button in it, instead.
When I receive a Push Notification, I want to jump to the middle tab on the tabbar and reset the tab (it has multiple table views that the user may have navigated into). I am able to jump to the tab using tabBarController.selectedIndex = 1; ... but how do I reset to the first view?
Implement UITabBarControllerDelegate on a controller class (perhaps your app delegate) and implement tabBarController:didSelectViewController: to pop all pushed view controllers off the navigation stack:
- (void) tabBarController:(UITabBarController *) tabBarController didSelectViewController:(UIViewController *) viewController {
if([viewController isKindOfClass:[UINavigationController class]])
{
[(UINavigationController *)viewController popToRootViewControllerAnimated:YES];
}
}
Can any one help me,
when i am using my UITabBarController delegate it is not working..
I called a delegate method like this..
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
[self.navigationController popToRootViewControllerAnimated:NO];
}
If what you're doing is subclassing a UITabBarController, then... oddly enough... you can get it working by setting itself as a delegate:
- (void)viewDidLoad
{
[super viewDidLoad];
self.delegate = self;
}
Then the didSelectViewController action will fire normally:
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
NSLog(#"View Changed");
}
Don't forget to add your UITabBarControllerDelegate class to your .h file:
#interface MyTabBarController : UITabBarController <UITabBarControllerDelegate>
#end
If you are using tab bar customizing by extending UITabBarController and trying to change tab bar selected index programmatically then it will not call delegates.
Please see the note inside "UITabBarDelegate":
// Note: called when a new view is selected by the user (but not programmatically)
This might help you
-(void)applicationDidFinishLaunching:(UIApplication *)application {
tabBarController.delegate=self;
// Add the tab bar controller's current view as a subview of the window
[window addSubview:tabBarController.view];
}
specify
UITabbarcontrollerDelegate in .h file
then
-(void)applicationDidFinishLaunching:(UIApplication *)application {
tabBarController.delegate=self;
// Add the tab bar controller's current view as a subview of the window
[window addSubview:tabBarController.view];
}
Read the documents to get a deeper understanding of the relationships between navigation controllers, tabBar controllers, and the view and navigation hierarchy.
Then review the code you've provided. Which view/controller is the container? You are popping the navigationController of self, which is not the same as the tabBarController. I don't think you actually need this method if you are looking to switch between tabs.
Try commenting out this method. It is an optional method in the UITabBarController delegate protocol. If you comment it out, you should get the default behavior of the tab controller, which should be to select the appropriate viewController and switch to the new view.
You typically only need to use this method if you want some action taken as you switch between view controllers.