I am working with the project of ios and doing well in it. But now i stuck at one place where i am having three views (Say 1stview, 2ndview, 3rdview). I am navigating to second view from first view and third view using the code line below.
[self.navigationController pushViewController:first view animated:YES];
How can i check on second view wheather i am navigating from first view or third view. So that i can use particular condition on it.
So please help me out regarding this issue. Your help will be much appreciable.
Take a variable in second View controller. When you are creating the object of it, set proper value into it. Later on when it will get pushed, you can use that value to take proper decisions.
In the file of FirstViewController you will write below lines:
SecondController *controller = [[SecondController alloc]init];
controller.flag = 1; //That means you came here from viecontroller 1
[self.navigationController pushViewController:controller animated:YES];
In the file of ThirdViewcontroller you will write below lines:
SecondController *controller = [[SecondController alloc]init];
controller.flag = 3; //That means you came here from viecontroller 3
[self.navigationController pushViewController:controller animated:YES];
Try to arrange thing so that the 2ndView doesn't know about 1stView or 3rdView, but instead just changes it's behavior according to how it was configured. So, let's say that when you're navigating to 2ndView from 1stView, 2nd should display with a green background and when you get there from 3rd it should use blue instead. Rather than telling 2nd which controller preceded it, have the preceding controller just tell 2nd what background color to use. Same goes for any other aspect of 2ndView's behavior.
The benefit of doing it this way is that you can change 1st or 3rd without having to change anything in 2nd, and you can later add a 4thView or 5thView that also use 2ndView without having to change 2ndView.
Implement the method – navigationController:willShowViewController:animated: from the UINavigationControllerDelegate Protocol Reference. Inside this method you can check the navigation stack to get the current view controller using several properties of UINavigationController. An example would be access the visibleViewController property.
As #Apurv pointed out you need some sort of identifier mechanism to be able to know which view controller the call came from. e.g.: viewController.view.tag
Related
I just have a quick question about recommended ways to implement a master-detail view hierarchy in iOS--the kind where selecting a row in a table on one screen pushes a details view for that item onto the navigation stack.
Specifically, should I reuse the same instance of the details view controller and just change its target and reload it each time, or should I instantiate a new instance of the view controller each time?
I'd prefer the first method, as it just seems generally more efficient, but I'm having trouble figuring out how to set the target and do the reload (especially the first time, when the view controller has not yet even been initialized--I'm using storyboards and that pretty much handles all of the initialization itself).
Or perhaps instead of setting the target on the child view controller, I could set it on the parent, such that each time the child view controller is shown, it reloads itself based on the parent selection? That actually sounds like the best bet so far, just looking for tips/warnings from anyone who's run into this before.
First, there's nothing wrong with creating a new view controller each time. If you use segues, that's what you'll get, since segues always instantiate new controllers. The detail controller will be deallocated when you pop or dismiss it anyway, so it won't persist.
If you want to use the same controller, you have to do your push or presentViewController in code. You can still setup the controller in the storyboard. Give it an identifier, but don't connect it up with a segue. In code, you check for the existence of your controller (you'll need a property for it), and if it doesn't exist, create it.
if (! self.detailController) {
DetailController *dvc = [self.storyboard instantiateViewControllerWithIdentifier:#"MyIdentifier"];
}
self.dvc.whateverProperty = self.somePropertyIWantToPass; // pass some date to it
[self.navigationController pushViewController:dvc animated:YES completion:nil];
I have a view in which a user selects an action to take and on that next screen there is a save and a back button. For both of the buttons the last line is dismissViewControllerAnimated:.
I need a way to make the 1st screen show only if the back button is used. save should send back to the main screen/rootViewController I am fairly new to iOS but not programming in general and just need a nudge in the right direction.
Could I set a bool flag to show or not? Maybe I can set the Tag on the view and then check that in the other screens on save/back? I assume I can check the parent view.
Sorry if this is a dup but I cant find anything specifically for this.
EDIT: I am not using a nav controller and am showing the views modally.
The answer will vary depending on how your UIViewControllers are structured and setup. If you're using a uinavigationcontroller then you can POP to the root view controller using:
[self.navigationController popViewControllerAnimated:YES];
If you're presenting your UIViewControllers modally, you can try to dismiss the presenting View Controllers of your modal view controller using the presentingViewController property:
[[[self presentingViewController] presentingViewController] dismissViewControllerAnimated:YES completion:nil];
You may also want to take a look at Unwind Segues if you're using a Storyboard:
What are Unwind segues for and how do you use them?
Finally, as far as determining whether the back button is pressed or another button - that depends on how the app is setup. You'll need to use your own logic (probably if / then statements or case / switch) to determine which button was pressed. You also may want to check out the sender argument in IBActions.
John, to have a UINavigationViewController return to it's root viewcontroller, you use:
[nameOfNavController popToRootViewControllerAnimated:YES];
The other guys are correct that the information you've provided is definitely not enough to determine exactly what you need to do.
You can use the presentingViewController property of a modal view controller to access it's presenting controller.
It turns out that I was using the terminology wrong. I am presenting all views modally and that is the issue, there is no navigation controller. I ended up using NSNotification to build a listener and had the main view controller listen and then dismiss the view and hence show itself. Worked a treat.
here is the link to the code I ended up with.
http://iphonedevsdk.com/discussion/114737/view-heirarchy-issues-possibly-from-the-camera
Hopefully this helps someone else.
I have a TabBar iPad app with a Split Controller in first tab. I follow this instructions to make it:
http://www.iphonedevsdk.com/forum/iphone-sdk-development/62217-simplest-way-make-split-controller-tab-bar-controller.html
Now my goal is to hide the root view controller of the split controller. I found a method to accomplish this:
http://vimeo.com/13054813
But that doesn't works for me, because it only works assuming the split controller is in the MainWindow.xib. But with the previous method, the split controller is added programatically.
Can someone help me to get my goal? Any idea would be appreciated.
Thanks in advance!
Here are the code:
http://dl.dropbox.com/u/27695108/MariCruz.zip
I hope you can help me.
Thanks!
You have a couple of problems with your project.
1 First one is that you are using a UITabBarController, that is why the code you found to hide the root view controller does not work.
Second one lays with your implementation of makeSplitViewController, where you are initializing twice your splitViewController, rootViewController, and detailViewController.
So, you have to fix point 2, so that you can correctly manage all of those controllers and then you should modify toggleSplitView so that you take into account the fact that you are using a UITabBarController. For example, replace the first few lines of that method with the following ones:
- (void)toggleSplitView {
NSArray *controllers = _tabBarController.viewControllers;
UIViewController* controller = [controllers objectAtIndex:1];
if (controller.view == splitViewController.view) {
[splitViewController.view removeFromSuperview];
splitViewController.viewControllers = [NSArray arrayWithObjects:rootViewController, rootViewController, nil];
splitViewController.view = detailViewController.view;
} else {
....
As you say, I am no accessing _window to check if the UISplit is there, because that view is not under _window, rather it is in the tab bar. The other branch of the if also needs to be rewritten according to the same criteria, but I will leave it for you.
The above code will work only with your second tab (the one corresponding to index 1); indeed, since you are overwriting splitViewController in makeSplitViewController, I can only use the element at index 1 in the tab bar without making further changes.
I'm developing a little example for iPad from a UISplitView XCode Template. It's formed by a root controller which is shown in the left of the window and a detail view which is shown in the right.
What I want to achieve is very simple (at least I think so) but I can't find in the documentation the way to do it.
I'd like to substitute the root controller (which appears fixed in the left) with a new controller (for example as response to a event launched when you push a button). I've tried this:
ColorPicker *controlador = [[ColorPicker alloc] initWithNibName:nil bundle:nil];
[self.rootViewController presentModalViewController:controlador animated:YES];
[controlador release];
What happens with that is that the new pushed controller fills the entire window, whereas what I want is that appears fixed at the left with the two columns format that were at the beginning.
You need to set the modalPresentationStyle to an appropriate value,
controlador.modalPresentationStyle = UIModalPresentationCurrentContext;
UIModalPresentationCurrentContext instructs the view controller to appear modally within the frame of the rootViewController.
Use pushViewController:animated instead may fix this. About ModalViewController, check document http://developer.apple.com/library/ios/#featuredarticles/ViewControllerPGforiPhoneOS/ModalViewControllers/ModalViewControllers.html
I have a navigation-based app that allows the user to drill down through hierarchies. Some of the child hierarchies have only one element in them, e.g.,
TopLevel1----->Level2a
TopLevel2 |->Level2b----->Level3a----->Level4a
|->Level2c
Instead of making the user tap 'Level3a', I just want to jump from Level2b to Level4a, but keep the Level3a view in the stack so when the user backtracks, it is visible.
I found some code here to simulate a row tap:
Simulate a Detail Disclosure Button press
When each level is loaded, I check to see if there is only one element in it. If so, I simulate the row tap. This all works initially, and the final view is loaded. But when I start backtracking through the view hierarchy, I get problems (it appears that the skipped views aren't loaded).
I think what I'm trying to accomplish is fairly simple, so I'm hoping someone on here can point me in the right direction.
You should be able to place a [self.navigationController pushViewController:level4 animated:NO] call in the viewWillAppear method for your level3 view controller. This will automatically push level4 on top of level3.
If it only happens some of the time, level3 can have a property to indicate when this behavior takes place.
I'm not 100% sure that would work, but that's what I would do.
You could directly [self.navigationController pushViewController:level4a animated:NO] and when that's done, set a new array of viewControllers, the navigationController propriety (an array that includes Level3a).
Here is a code sample, in you didSelectRowAtIndexPath:
[self.navigationController pushViewController:level4a animated:NO]; //Push the level 4 first
NSMutableArray* mutableViewControllers = [self.navigationController.viewControllers mutableCopy];
[mutableViewController addObject:level3a atIndex:3]; //Add the level 3 manually
self.navigationController.viewControllers = mutableViewControllers;
[mutableViewControllers release];