I have two views and i used two view controllers. From the main view i want to initialize the button in the second view with a certain text.
If I press the button in the second view, then i can store that button reference to a global UIButton, and change the text then onwards.
But the very first time, how can I initialize the button text in the second view from my main view with a particular text ?
You should not do that: every controller should be responsible for its own view. Full stop.
You can always set some poperty on the second controller and use it when the second view appears on the screen to change whatever you like.
you use delegates & #protocol to access other class example,
refer ex, ex1, link
Not sure how you did this. But if you post some code, it will be helpful. If you already have the above code working, then you need to have the following in order for what you are expecting to work.
Say you have ViewControllerA, ViewControllerB as the two view controllers. You can definitely initialize the text in the button when you create the XIB file.
But I am assuming that you want to do this programatically. If you want to access a button in another view controller, you need
a. Access to the other view controller.
b. Once you have access to the other view controller, access to the UIButton variable in that view controller.
So you can do the following in the ViewControllerA code,
-(void)changeButtonTextOfVCB{
viewControllerB.button setTitle:#"MyTitle" forControlState...
}
and you can have a button in viewControllerA, which will trigger the above method.
Having said this, I am not sure whether you have the whole thing working, where you can even switch between the view controllers
If you make a button in FirstViewController and want to change button properties like title..etc from the second view, then you should make properties in SecondViewController
#property (nonatomic,assign) UIButton *button;
when you navigate firstViewController to secondViewController just pass the button Object like
obj = [SecondViewController alloc]...]
obj.button = button;//(FirstViewController button object)
Related
I have a UIViewcontroller on which I have added a UIView as a subview and then added another UIView as another subview over the first view.
Now I want to call a method in the UIViewController from the last UIView. All of these views are custom views and have been created as different classes.
What would be the best way to call this topmost view from the child of the child?
You cannot add a view as a UIViewController's subview. I believe you added it as a subview of the controller's view. I do not understand what you mean to ask in the question. Please correct me if I'm wrong.
I assume you want to call a method in the UIViewController on some user interaction. If this view (the child of child)is a button, you could simply do this:
[button addTarget:nil action:#selector(methodToCall:) forControlEvents:UIControlEventTouchUpInside];
A nil target will result in the method methodToCall in the UIViewController to be called.
If you don't see a call there, make sure the view hierarchy (all predecessor views in it) is user interaction enabled.
A better approach (If you haven't subclassed UIButton) would be to create a protocol for your custom views, specify a tap gesture recognizer, specify a delegate and send call a method in the delegate whenever you receive a tap.
The whole point of a view controller is that it's in control of the view. You shouldn't be adding knowledge to the view which requires it to know to pass information to the controller. The view should either have UIControls on it and the controller sets the appropriate target and action or the controller should add gestures to the view and, again, specify appropriate target and action.
I can not get what you want exactly..if you want simple topmost view then you set tag of this view when you call addsubview .and every time increment tag when add subview and decrement tag when remove subview.then you easily get topmost view with help of current tag.
Do like this,
In TopView.h
#property (nonatomic, assign) YourViewController *ViewController_object;
In TopView.h
-(void)dealloc {
[super dealloc];
ViewController_object=nil;
}
-(void)your_method {
[ViewController_object method_from_VC];
}
hope it will helps you...
I have two UIViewControllers. In first UIViewController I have a UITableView as a subview. When any one of the UITableViewCell is selected, a UIView(as a subview) will be displayed, which have 9 buttons. When any one of the button is pressed, Second UIViewController will be presented. When user press custom back button on second UIViewController, First UIViewController have to be presented with all previous selected UITableViewCell and corresponding subviews open. How to achieve this. Is there any process to save UIViewController's state at a desired time.
Any suggestion will be greatly appreciated.
If your are using a Navigation controller, navigating from one controller to another, your parent view controller will not be deallocated. Hence you can maintain state of that first view controller by means of properties or something else. When viewWillAppear is called for that controller, you can make use of that and update the controller accordingly.
I've created a UIViewController, and insert a container view in it, which embed a UITableViewController. As the image described above.
When user click the Table View Cell, I'd like to add a UIBarButton on the Navigation bar.
But, how can I manage this? I can rise the DatePicker when click on Table View Cell, but when I call self.presentingViewController in table view controller implementation file, it returns (null), same as when I call self.parentViewController
You're probably trying to access the parent controller too early. If you log self.parentViewController in viewDidLoad, it will return null, but it should return the correct controller from viewDidAppear, and certainly from the didSelectRowAtIndexPath method. Using parentViewController in this context is correct, not presentingViewController.
I'd suggest to implement the UITableViewController Delegates and Datasource Methods in the ViewController itself.
That way you don't have to worry about accessing the ViewController containing the UITableView.
I've been reading the Head First iPhone Development book and I understand how to get to a new view from a table but how exactly would I be able to get to a new view or view controller, by just simply pressing a button? Is that even possible?
I mean there are some apps where you click a button, not a table cell and it loads a new view. How exactly is that done? If someone could help out a newbie it would be greatly appreciated!
I think what you're looking for is a modal vew controller. THis presents a modal view like you described on top of everything else. If rootViewController is the view controller that is displaying your current view, and myNewViewController the view controller you want to display modally:
[rootViewController presentModalViewController:myNewViewController animated:YES];
There's plenty of examples of this kind of thing on the net, just search for presentModalViewController
Like bpapa said in the comments, it's hard to be specific without code. However, generally what you want to do is:
Build a navigation controller that contains one original view.
Create a button in your original view using the Interface Builder.
Build a callback method (usually defined with IBAction) that is run when the button is pushed.
In that callback method, create a new view and push it onto the navigation controller the same way you would using a table view cell.
Alternately, if you only want one level of hierarchy, you could use a modal view controller; instead of pushing onto the navigation controller in the last step, just present the modal view controller.
The general answer is that you have an object that manages which view controller loads when.
The most commonly used is the UINavigationController. It is a UIViewController that instead of controlling views, controls other view controllers. It works like a simple stack. You push views you want to display onto the nav's controller stack and when you want them to disappear you pop them off.
A common (though sloppy) way of using a nav is to make it a property of your app delegate. Then anywhere in your app you can references it by:
UINavigationController *nav=[[[UIApplication sharedApplication] delegate] navigationController];
The view controller for the first the user sees is held in the nav's topViewController property. If you want to load a view based on a user action in the topViewController.view, you would have something like this:
- (IBAction) loadNextView:(id) sender{ // Action called by a a UI event such as a button press.
UINavigationController *nav=[[[UIApplication sharedApplication] delegate] navigationController];
UIViewController *nextViewController=...// load from nib, connect with IBOutlet, create programmatically
[nav pushViewController:nextView animated:YES];
}
The first view disappears to be replaced by the next one. To return to the first view, you have a method in the next view controller like so:
- (IBAction) unloadSelf:(id) sender{ // Action called by a a UI event such as a button press.
UINavigationController *nav=[[[UIApplication sharedApplication] delegate] navigationController];
[nav popViewControllerAnimated:YES];
}
... and the nav returns you automatically to the previous view regardless of what that view was.
When you first start out, especially if you use Interface Builder, the structure of the app is largely hidden. Behind the scenes all view controllers and their views exist in a hierarchy of some kind that leads back up to the app delegate. You should train yourself to think in hierarchal terms even if it is not immediately obvious how that hierarchy is constructed.
Fundamentally, what I want to do is within, for example, ViewControllerA display ViewControllerB and ViewControllerC. How would I do that?
Thanks in advance.
You don't display view controllers, you display views. Having said that, you can do something like this:
UIViewController *a = ...;
UIViewController *b = ...;
[a.view addSubview:b.view];
Now, having said that, you shouldn't do it. Tons of stuff does not behave properly, because there are tons of undocumented interactions between UIView, UIWindow, and UIViewController. There is nothing in the documentation that says it won't work, but random things stop behaving properly (viewWillAppear: on the interior view's VC doesn't get called, etc).
If you need this functionality, you should file a bug with Apple.
The default template for a navigation view controller should do what you want assuming you want two different screens (not two different sections on the same screen). Whenever you want to change the view from the current one to another, just tell the navigation controller to push it on the stack:
[self.navigationController pushViewController:viewBoards animated:YES];
The default navigation view controller gives you a root view controller with a navigation view controller in it. It also gives you one view controller called MainWindow. Just add as many copies of MainWindow as you need to get your functionality.