I created a subclass of UIViewController. In it I have two properties of:
#property (nonatomic, retain) IBOutlet UIView *presetsView;
#property (nonatomic, retain) IBOutlet UIView *customView;
I added a new UIView to my .xib and put some UI elements in it. I want to hide one view, and show the other based on when the UISegmentedControl is pressed.
My question is in Interface Builder, my original View that was provided me by IB, has an outlet connected to it already to File's Owner. Because I have my own two views, presets and custom, how do I make the outlet connections in IB?
I tried deleting the original view that was provided by IB and dragged two new UIViews to the canvas. I then connected an outlet to each. When I push my new viewController, I get an error that there is no view for my viewController. Then when I connect the File's Owner to the "view" outlet that shows up for the view I want to show first, the application runs. I wasn't sure if this was the correct way, and why it would be the correct way. Does the ViewController always need a .view property an outlet to it? Is that why I needed to do this? Thanks.
Write action method for UISegmentedcontrol and implemnt method like below
-(IBAction) selectMessageType {
noResultsPriview.hidden = YES;
//[activityIndicator startAnimating];
switch (msgOptionControl.selectedSegmentIndex) {
case 0:
//code for view1
break;
case 1:
//code for view2 break;
case 2:
//code for view3
break;
case 3;
//code for view4
break;
default:
break;
}
}
Yes every UIViewController has a single root view. It must be able to construct that view when its -loadView method is called either by loading that view from a nib file (and setting its view property as a result) or by creating it programmatically.
In your case leave the view property view alone and don't try to swap that around. This root view will have already have been added to the window and changing the controller's reference to point to some other object will just cause confusion and undefined behavior. Instead add both of your views as subviews of the controller's root view and hide or show then as needed.
UIViewController must have a valid UIView so in your case it can be the original UIView created during the XIB creation. Your two UIView properties are correct. All you have to do is to setup in IB the connection between your presetsView and the original UIView so that you can later switch back to it, then you need to connect customView to your other UIView.
So after you finish your original UIView will have two connections, one as a view of UIViewController (owner) and one as a presentsView.
Those connections are only pointers so that you can use them to manipulate objects in the UIViewController.
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'm having some problems because I don't know how it can be done. Someone help me please.
Problem:
I have a project with a UIViewController class with created all time when I create a new project in Xcode. In this viewController, I have a xib file for designing in Xcode.
What I need is to create some views and design them in Interface Builder like this:
But I need these views to be UIViewControllers, not UIViews.
The project should look like:
So I don't know how I can do this in IB but I can do it from source code in ViewController.m
tab = [[TabBarController alloc] initWithNibName:#"mytestview" bundle:nil];
[tab.view setFrame:CGRectMake(100, 100, 400, 600)];
[self.view addSubview:tab.view];
But it's not my views it's a different object, and if I want to change position or size I must do it from code. How I can do same things in Interface Builder?
Let's consider following example based on Master-Detailed Application for iPhone only.
So, add new view controller in newly created project in Xcode:
I called it NewInsideViewController. Create it without xib:
Open DetailViewController.xib. Drag View Controller and View(*) objects from library to Objects area like this (I changed view's color to LightGray):
Choose this View Controller and change its Class from UIViewController to NewInsideController at the Identity Inspector:
Assign our View(*) to NewInsideController as a view:
Now all main actions in IB finished. We need to create instance of NewInsideController in our DetailViewController. You can do it by hand, but Xcode has a nice feature - drag-n-drop ;)
I called this property as myNewInsideController and DetailViewController.h looks like this:
#import <UIKit/UIKit.h>
#import "NewInsideController.h"
#interface DetailViewController : UIViewController
#property (strong, nonatomic) id detailItem;
#property (strong, nonatomic) IBOutlet NewInsideController *myNewInsideController;
#property (strong, nonatomic) IBOutlet UILabel *detailDescriptionLabel;
#end
Well, now our NewInsideController ready to work and manage its view. Let's add button and action to that view in order to verify this:
Write some code in IBAction in NewInsideController.
- (IBAction)insideButtonClick:(id)sender {
float rPart = arc4random()%100/100.0f;
float gPart = arc4random()%100/100.0f;
self.view.backgroundColor = [UIColor colorWithRed:rPart green:gPart blue:0.5f alpha:1.0f];
}
Run program.
If I understand the question clearly:
You have a parent view and controller, coming from a XIB.
You have placed subviews into the parent view.
You're wanting each subview placed into the parent view to have it's own (custom) controller, but you don't know how to add view controller's to your hierarchy (XCode will not let you drag view controllers into a view's canvas).
So, to answer the question succinctly: Let's assume you have a handful of custom UIViewController's in your project (each view controller consisting of a .h and a .m). Remember that you if you are laying these out in the context of the parent, they shouldn't have their own XIBs (you cannot nest XIBs in IB). What is important to note here is that you should only "layout" the interface in one location. If you want to have a XIB for each subview, this is not the correct approach. What you can (not should) do, however, is have several custom viewControllers, each connected to it's own view sitting within your parentView, and you can have the outlets of your sub view controller's set to objects in this parentView. Phew, kinda messy. The other thing you'd need to be aware of is that your parent view controller would need a reference to each of it's sub view controllers in order for you to be able to access those sub-controllers and their outlets programmatically, so for each sub view controller you add, you would also need to add an IBOutlet in your parent view controller pointing to each subviewController:
ParentViewController.h
#property (nonatomic, weak) IBOutlet CustomUIViewController *firstCustomController;
And then for example to set the background color on the view of your first custom subview/controller:
ParentViewController.m
[[[self firstCustomController] view] setBackgroundColor:[UIColor whiteColor]];
Open up your parent view controller in IB. If you look in your drawer of available objects, you'll find a generic UIViewController object. Drag this into your parent view controller (NOT onto it's views canvas, rather into the parent UIViewController object itself as seen in the left-column of IB builder). Select the generic view controller you've added and set it's class to your desired UIViewController subclass. Now, when your XIB loads, it will instantiate an instance of your custom view controller along with whatever you've added to it's canvas.
Finally, drag a generic UIView onto your canvas, placing it inside your existing controller's view (your screenshot already shows this as done). Right-click your custom view controller, and connect it's 'view' outlet to the view you added.
Now when you run, your custom view controller has a view that is on the screen that is the view of your custom controller subclass, and you didn't do any of it in code.
So now that you've done it, consider whether or not it is the best choice: Nested view controllers are messy to build (as you've seen) and aren't necessarily a good design decision: http://blog.carbonfive.com/2011/03/09/abusing-uiviewcontrollers/
Although iOS5 does support nested view controllers, personally I'd avoid using them. I value a best practice dictating one screen = one view controller.
You never, EVER, want to take views which are already under the control of a certain view controller, and make them subviews of another view controller's view.
View Controllers are the C part in the MVC design pattern - They are in charge of controlling a view (and its subviews). You can't take a view which is being managed by a controller, and stick it as a subview of a different controller's view - If you do that, it becomes ambigous who is responsible to manage this view.
Even though this "sticking" might be possible technically, it creates code which is hard to understand, hard to maintain, and most importantly - will cause bugs due to the unclarity of who is responsible to manage the view, and due to the fact that Apple's View/Controller framework doesn't support this.
For example: If the device is low on memory, Apple makes sure to unload views which are not currently displayed. Apple relies on the view controllers hierarchy to know when it can unload views. If you stick the view controller's view in another view controller's view, it's very likely that the view will never be unloaded even if it isn't visible.
Instead of breaking the view controller hierarchy, do one of the following:
Just add subviews to your view normally, either in interface builder, or in -viewDidLoad: to add them programatically, or (rarer) override -loadView.
Use view controller containment, either with Apple's ready-made ones (UINavigationController,UISplitViewController etc.) or with your own container view controllers (iOS>5).
Display view controllers modally.
The bad idea of breaking a view controller hierarchy is indeed very common and often seen in 3rd parties, probably because it's so easy and seemingly straightforward. Unfortunately this causes the aforementioned bugs :-(
I really recommend to everyone participating in this thread and comments to read Apple's View Controller Programming Guide, and watch WWDC 2011 "View Controller Containment" video.
I know this has been discussed a number of times but I still have some problems getting around the problem, so any help would be appreciated. I have a class MyView which subclasses UIView. So far so good, in this custom class I basically configure the layout, UI, etc.
Now, I have a separate UIViewController and what I want to do is create an outlet for that custom view. In the view controller's Nib I set the view's class to that of my custom view and connect it to the outlet, but I can't see anything apart from a blank view.
How and where do I load the view from nib? Do I simply say self.theOutletForMyCustomView = load from nib or is it something else? Thanks for your help
First of all, you have to set the name of your CustomView inside your UIViewController nib file like that
Then, you have to retain your property like that inside your UIViewController interface :
#property (nonatomic, retain) IBOutlet CustomView *myCustomView;
or an ivar should work, but assign an IBOutlet property doesn't work.
And if you customize your CustomView inside your CustomView class implementation. Beware of doing your initialization in awakeFromNib or initWithCoder: instead of initWithFrame:
I'm using a UITableViewController and want to add a searchbar.
My options are [self.tableview addSubview:searchBar] or self.tableview.tableHeaderView = searchBar
Both options will scroll the searchbar along the rest of the tableview, which I understand. But is there a way to lock elements up, instead of using a UIViewController or changing the frame origin on scroll?
I'm thinking of a way to get above the current view hierarchy and add a subview onto that.
I tried the opposite approach, to add a view to the superview and bring that to front
[[self.tableView superview] addSubview:searchBar];
[[self.tableView superview] bringSubviewToFront:searchBar];
}
but it didn't work.
UITableViewControllers are UIViewControllers that have their main view property being an UITableView. Thus this UITableView do takes all the screen.
The approach you are looking for is to use a standard UIViewController whose view is a standard UIView, and add your UISearchBar and the UITableView as a subview to it in IB.
To do this, simply:
Change the class of your view controller and instead mention that it conforms to the tableview-associated protocols : change #interface UITableViewController to #interface UIViewController <UITableViewDelegate, UITableViewDataSource>
Add a #property(nonatomic, retain) IBOutlet UITableView* tableView property to your header file, and the associated #synthesize tableView; statement in the implementation. Don't forget to set this property back to nil (self.tableView = nil) in your dealloc for good memory managment
Link your UITableView instance in InterfaceBuilder to this newly created IBOutlet.
Thus you still have a UITableView but this won't be the main view that takes all your screen; instead you can layout your tableView like you want and make it take only a part of your screen, and position the UISearchBar above it.
Another approach would be to use the UISearchDisplayController to manage your UISearchBar.
I'm working on an app that has three table view controllers in a navigation stack. The root view controller and the second VC have toolbars, but I want to add a subview to the second view controller like this. (The color is just there for visualization.)
I want to add the view programmatically, since I haven't been able to do it with IB without major headaches. Right now, I've been able to kind of get what I want by drawing a UIView in the second view controller like this:
- (void)viewDidLoad {
[super viewDidLoad]
UIView *detailView = [[UIView alloc] initWithFrame:CGRectMake(0, 392, 320, 44)];
detailView = [UIColor redColor];
[self.navigationController.view addSubview:detailView];
[detailView release];
}
The problem with this approach is that once the UIView is loaded in the second view controller, it stays loaded and is drawn in the third and root view controllers. I've tried a variety of methods of removing the UIView, including setting the detailView to nil in viewDidUnload, calling removeFromSuperview in didSelectRowAtIndexPath (which removed the view from the whole stack).
I've also tried adding the subview to self.view, but that pushes it below the visible area of the table view, so I have to scroll up to see it, and it snaps back down when I let go.
Clearly, adding this subview to the navigation controller is not the best way to do what I want, but I'm at a loss as to where to go from here.
As you've already discovered, you definitely should not be reaching up into the navigation controller's view.
You want your SecondViewController to be an UIViewController that implements the UITableViewDelegate and UITableViewDataSource and whose view lays out the UITableView and the UIView you wish to use for your stationary 'footer' in it's own main UIView.
It helps to keep in mind that UITableViewController is ultimately is just a convenience for creating a view controller whose view consists entirely of a UITableView.
Anyway, rather than attempt to put a pile of that code inline in this answer, you can browse it (or svn co) from this read-only svn repo.
EDITED (now that it's not midnight, putting some code/explanation directly in answer):
For the controller to be pushed onto the nav stack that needs the footer create a new UIViewController-based class (do NOT check the 'UITableViewController subclass' box in the template selection dialog).
Add instance variables for the UITableView and the UIView that is to be the extra bottom view.
#interface SecondViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> {
UITableView* tableView;
UIView* customFooterView;
}
#property (nonatomic,retain) IBOutlet UITableView* tableView;
#property (nonatomic,retain) IBOutlet UIView* customFooterView;
#end
In IB add a UITableView and UIView to the existing root view for the controller and lay them out as desired (probably worth altering the auto-resize parameters too if your app can be used in both landscape and portrait). Hook up the two views to the outlets defined for them in the "File's Owner" and also ensure you hook up the UITableView's delegate and dataSource properties to point at the "File's Owner."
Then just implement the UITableViewDelegate and UITableViewDataSource protocols as appropriate for your application.
If you want to lay out the entire 'footer' view in IB then go right ahead. Otherwise you can easily add items programmatically in viewDidLoad (and remember to tear it down in viewDidUnload).
I don't like the approach. You should put your table view inside another view, and put your detail view together in that view.
Despite of that, I think you can remove your view in viewWillDisappear method of your view controller. I also notice that you did not keep your detailView as a private variable, which you should do because you need to reference it when removing it later (I still wonder how you have done it.)
Note that viewDidUnload is called in case of view unloading (i.e. releasing from its controller), so it is not related to navigation.
Not sure which behavior you're looking for but try one of these:
Assign the detailView to the tableFooterView property of the tableview on the second VC.
Reduce the height of the table view and add the detailView to self.view.