I have googled for many days but don't find out. I just know how to do by IB, but not by programmatic way. I think [addsubview:view] is just only add sibling view, not parent-childview. Thanks guy for reading.
It is easy:
//allocate a view (or take it from IB or from where you want)
UIView *newView = [[UIView alloc] initWithFrame:CGRectMake(10,10,100,100)];
//add the view on the actual view (or any other view)
[self.view addSubview:newView];
So this is a parent-child case and not a sibling view.
In fact by [newView superView] you get the parent view.
You might be getting confused by the difference between subviews and child view controllers, which are what's used when we have Container View Controllers that manage & display a number of child view controllers.
Take a look at the "Implementing a Container View Controller" section of Apple's UIViewController documentation, and you'll see how they describe how child view controllers work.
And, to answer your question specifically, here are the four methods that involve Child View Controllers (from the documentation):
Here are the essential methods you might need to call:
1) addChildViewController:
2) removeFromParentViewController
3) willMoveToParentViewController:
4) didMoveToParentViewController:
And, of course, if you're really talking about subviews, there are a bunch of other people excitedly providing all sorts of answers to your question along this front. Hopefully you'll have the correct answer for your problem really quick.
You can subclass a class to achieve this.
Example:
#interface MSCustomView:UIView
Here UIView is the parent class and MSCustomView is the child class
The [UIView addSubView:] function adds a view as a child view to the view you call it on i.e
[view1 addSubView:view2] will add view2 as a child to view1.
In the Apple docs:
http://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/UIView/UIView.html#//apple_ref/occ/instm/UIView/addSubview:
addsubview does just that. If you'll keep adding subviews to the same View you will basically create more siblings to that subview
From the iOS Developer Library:
Views can embed other views and create sophisticated visual
hierarchies. This creates a parent-child relationship between the view
being embedded (known as the subview) and the parent view doing the
embedding (known as the superview).
https://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIView_Class/UIView/UIView.html
AddSubview add a view into parent hierarchy . IOS provide insertSubview too for ad child view. This
http://developer.apple.com/library/ios/#Documentation/WindowsViews/Conceptual/ViewPG_iPhoneOS/CreatingViews/CreatingViews.html
provide a better approach to understand about it.
You can add sub view by [parentview addSubView:childView] in the syntax both childView and parentview will be of UIView type.
Related
Can any one explain when should we add a UIViewController as ChildViewController?
What is the benefits of adding it as ChildViewController instead of subView?
Please help me to understand the purpose of ChildViewController.
When you add a view controller as child view controller, the parent view controller will hold a strong pointer to the child view controller so it doesn't get released instantly. This does not automatically add child's view to parent's view. So you will have to call them both.
I only used it when I needed to create multiple view controllers to be inserted in another view controller and didn't need to directly access it.
its all about UI and code management if you are using subview to achieve what you want to implement inside your app you need to code for your view inside same viewcontrollers class but something interesting i found by creating childviewcontrollers.
empowered to work on a seprate viewcontroller will invoked along with its parent viewcontroller along with its seprate class.
infinite controllers that will be updated tapping a button.
Creation of childViewControllers can be achived by implementing containerView.
or you must have a look of this link hope its helpful to understand.
I am making an app where I have a container view that is half the screen of my view controller. From the container view controller's class I am trying to access and manipulate a view that sits out side of the container view. (picture below)
I am trying to access and add items to the scroll view from the container view class like so:
parent = (GFProfileViewController*)[self parentViewController];
UIScrollView *scroll = (UIScrollView *)[parent.view viewWithTag:222];
parent.titleHolders.contentSize = CGSizeMake(320 * 4,60);
UILabel *testLabel = [[UILabel alloc] init];
[testLabel setFrame:CGRectMake(0, 0, 100, 40)];
[testLabel setText:#"My Test label"];
[parent.titleHolders addSubview:testLabel];
scroll.backgroundColor = [UIColor blueColor];
how ever does not work. I tried even accessing the view from the parents "view with tag" method.
neither works.
I know the code is fine because when I move it to the parent vc all works as expected. I need to be able to manipulate the view from the container though. Can anyone help?
As nhgrif says, don't do that.
You should treat another view controller's views as private.
Again, as nhgrif says, create a public method in the parent view controller that takes the information needed and does the displaying itself.
If the view controllers are just being initialized then the parent view controller's view hierarchy may not exist yet. In that case you'd want to set properties to hold the value(s) you want to display, and then display them in your viewWillAppear method.
With storyboards and iOS >= 6, you can set up the child view controller using an embed segue, and then in your prepareForSegue method you can set the parent view controller up as the child view controller's delegate. That's a clean way to have the child communicate back to the parent. (I have a sample app on github that demonstrates this technique if you need a more detailed explanation.)
As far as programming ethics, correctness, good practices and whatnot, I think others have that covered. What you want to do surely isn't the clean way to go, but I often find myself going for such shortcuts, but you really need to know what you're doing, and if it isn't coming back to bite you later. The good thing is that it takes one line of code to achieve and has very low overhead. The problem is that such approach is highly dependent on the view structure, so if you change it, it will no longer work.
With that being said. What you tried doesn't work because the 'parentViewController' property isn't set on any arbitrary view. It should only be defined on the main view of the view controller, the one you can access from 'viewController.view'.
I will assume from your comment that your view structure is something like:
UIView
UIView
UIScrollView
Container
So basically starting from Container you need to go up one level and then down to UIScrollView like this:
UIScrollView = [((UIView*)[self.superview.subviews objectAtIndex:0]).subviews objectAtIndex:0];
I am unsure if you can search by tag from the upper view, since the one you're searching for is somewhere nested inside, farther than one level down. Assuming you can actually do that, this should also work and be more fail proof.
UIView *upperView = self;
while([upperView superview]){
upperView = [upperView superview];
}
UIScrollView *scroll = [upperView viewWithTag:222];
This might be a stupid question, but I'll shoot.
I made a little test project to test out a concept I had for a sliding view controller type of thing. I naively assumed I could create a UIView (let's call it peekView) with an outlet in a controller, and call something like [slidingControllerSlideFrom:self.view] from any visible view controller, the implementation of such being:
- (void)slidingControllerSlideFrom(UIView*)controllersMainView
{
// push side controller to top of navigation stack
self.peekView = controllersMainView;
// sliding animation
}
But there is no effect. No crash, no warning, no change of view in the pushed controller.
Of course, the pushed controller crashes when trying to add self's view as a subview, but assigning it to a predefined UIView just results in nothing.
So, why? And if a mere 'why' is not enough of a question- what happens when I try to assign one controller's view another controller's subview, and what was the reason for designing UIKit where you cannot set views from self.view?
To do that you have two options:
1 - If the controller in the peekView is always the same one in a given scene, use a "Container View". Those are explained here. Basically, they allow you to add a view in your scene that is managed by another controller.
2 - If the controller in the peekView depends on different conditions, you will have to create something similar to a custom tabbarcontroller. That means that you instantiate the controller that you need, add it's view as a subview of peekView (not assign the controller's view to the peekView itself) and then use didmovetoparentviewcontroller to notify the child controller. This question might help.
UPDATE:
Just saw your comment, so let me answer what you actually asked: The peekview property is actually just a reference to the real UIView you placed in the screen. When you do this:
self.peekView = controllersMainView;
You are changing the reference, but no the view object itself. That's why you are not seeing any changes. There are ways of adding a new view to the controller from code, but it is much simpler to simply use addSubview to add your controllers view to a UIView that is already in the controller.
Check out the discussion here: subView Slide up from bottom of the screen
and here: SubView slide in animation, iphone
Hopefully that gives you a bit of framework on how to approach this task!
I cannot find where the view and viewcontroller get hooked? Is it in the xib file?
I learned that each viewcontroller can control several views, but where are those two get hooked?
I recommend you to read the whole ViewController Programming Guide if you have doubts like that:
ViewController Programming Guide
In case you want to jump right to your issue, check this section:
Resource Managment in ViewControllers
You can find a nice graph explaining where the views are created and linked in the ViewController:
A ViewController is just that, a class to manage the UIViews (there will be many) that it contains. The main view is automatically wired up for you and you are responsible for wiring up all the other views you add. Keep in mind that UIButtons, UILabels, UIViews, etc are all objects that inherit from UIView.
Like Antonio indicated, start with the Apple docs:
The view controller has its own view. Each child view (subview) view has a parent view (superview). You can nest views inside of views. In your case, the top view in the hierarchy is the view controller's view.
At design time, you can add a child view to any view in Interface Builder by simply dragging a new view onto the parent view. You can also adjust the view hierarchy from the Document Outline in Interface Builder.
When creating a view hierarchy in Interface Builder, the view hierarchy is stored in the .xib file.
At run time, your views are instantiated from the information in the .xib file, and each child view's superview property points to its parent view. Each view also has a subviews property that lists each of its child views.
You can add a view to any other view at run time by instantiating a new view and passing it to the parent view's addSubview method. Obviously, once instantiated, you can alter the view hierarchy by setting the superview and subviews properties and calling related methods.
I have one nib file and have two view on it, i want to know how cold i change view from one to the other.
thanks for help
Two methods you should be overly familiar with:
[parentView addSubview:childView];
[childView removeFromSuperview];
You should not just be thinking in views, which are arranged in a hierarchy, but also of view controllers, which have a different but vaguely related hierarchy of their own. Check out the View Controller Programming Guide
Also, the UIViewController Class Reference and UIView Class Reference are things you should be overly familiar with.
if you have two views on other view, and they lies under each other, you may use bringSubviewToFront method to show desired view.
you can also use hidden property of UIView object to show/hide custom view:
//method 1
[parentView bringSubviewToFront: myView1];
//method 2
myView1.hidden=YES;
myView2.hidden=NO;