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
Related
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];
}
viewWillAppear is called both when going to the view and when coming back to the view from other views.
I want to select(highlight) and fade-out a cell only when coming back from other views.
Is there a delegate method to do this?
I'm using UINavigationViewController.
If you're on iOS 5, you can use these new properties:
These four methods can be used in a view controller's appearance
callbacks to determine if it is being presented, dismissed, or added
or removed as a child view controller. For example, a view controller
can check if it is disappearing because it was dismissed or popped
by asking itself in its viewWillDisappear: method by checking the
expression ([self isDismissing] || [self
isMovingFromParentViewController]).
- (BOOL)isBeingPresented __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_5_0);
- (BOOL)isBeingDismissed __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_5_0);
- (BOOL)isMovingToParentViewController __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_5_0);
- (BOOL)isMovingFromParentViewController __OSX_AVAILABLE_STARTING(__MAC_NA,__IPHONE_5_0);
In your code:
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
if (!(self.isMovingToParentViewController || self.isBeingPresented))
{
// animate
}
}
EDIT:
If you're using a UITableViewController, setting the property -clearsSelectionOnViewWillAppear to YES will do this for you. You only have to do it manually if you're using a regular UIViewController with a UITableView subview.
If you are targeting iOS 5, you can use [self isBeingPresented] and [self isBeingDismissed] to determine if the view controller is being added or removed from the nav controller.
I'm also suspecting that you could improve the logic of when you select/deselect the cell in your table view such that it doesn't matter whether the view controller is coming or going.
The usual way to do it is this: when someone selects a row in the table view in view controller A, it gets selected/highlighted and you push a new view controller B. When view controller B is dismissed, you animate the deselection of the table view row in viewDidAppear (so the user can see it fading out) in view controller A. You wouldn't worry about whether view controller A has just appeared or is re-appearing, because there would only be a selected table view cell in the appropriate case.
viewWillAppear is getting called when the view appears
after the viewDidLoad
after you dismiss or pull a view controller
You could change the viewWillAppear to the following
- (void) viewWillAppear:(BOOL)animated
{
static BOOL firstTime = YES;
if (!firstTime)
{
//Do your alpha animation
}
firstTime = NO;
}
In your UINav Controller you could create a "lastView" property and have each of your view controllers (that are controlled by your UINav Controller) set this property on "viewWillAppear"... in your target view... the one you want to do the highlighting and fading you could check this property of the UINav Controller and see if it's NIL or not.
That's just one way to do it. This wouldn't work if you pop up a modal or the like.
In my App i have a situation where i Programmatically change the selected index of a tabBarController like this
[self.tabBarController setSelectedIndex:0];
and go back to my tab containing a UITableView' at this point i need to make some actions on my tableView
i tried to use viewWillAppear and it didn't get there, i tried to make the view delegate like this
#interface ThirdViewController : UITableViewController < UISearchBarDelegate,UINavigationControllerDelegate, UITabBarDelegate>
- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController{
it didn't work
any one know how to do it?
I noticed that your class ThirdViewController implements UITabBarDelegate, while tabBarController:didSelectViewController: is in fact a method of UITabBarControllerDelegate protocol.
Try this below code:
self.tabBarController.selectedIndex = 1;
or
[self.tabBarController setSelectedIndex:1];
Thanks..!
UPDATE :
you can set delegate for tabBarcontroller viewdidLoad method below code:
tabBarController.delegate=self;
the solution for me was to make [[controller alloc]init] and activate a function doing the things i need in the controller im moving to
I've made this simple function to select programmatically view controllers inside my UITabBarController.
-(void)selectVCfromIndex:(int)index{
self.selectedIndex = index;
[self tabBarController:self shouldSelectViewController:[self.viewControllers objectAtIndex:index]];
}
In the shoudSelectViewController protocol i have specific code for presenting view controllers and in this way it runs when tabs change both programmatically and by user interaction.
I want screen 1 to be shown when tabbaritem 1 is clicked and if I change some settings, i go to different view, , when I click the tabbaritem 1 again I want to show screen 2.
I have a UITabbar based app and the MainWindow.xib has different tabs loaded before with views.
How do I change it programmatically?
Please help
just put the code for the views to be created in the method viewWillAppear instead of viewDidLoad. This is being called each time go go back to your tab 1
Implement below method in your App Delegate
- (void)tabBarController:(UITabBarController *)controller willBeginCustomizingViewControllers:(NSArray *)viewControllers {
UINavigationController *nc;
nc = viewController;
if(controller.selectedIndex == 3){
[[nc.viewControllers objectAtIndex:0] replaceSubView];
}
}
Here,
if(controller.selectedIndex == 3)
3 = your viewcontroller index in which you want to change subview.
And "replaceSubView"
is your method in view controller in which you want to change subview.
Let me know in case of any difficulty.
Cheers.
Turn MainWindow or AppDelegate into UITabBarDelegate, than use
- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item
to caught tab selections. When tab you need is selected, use image property of UITabBarItem to set image you like.
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.