I have a .xib file for my viewController. It contains a TableView and a UIView. The UIView is backed by a custom class - CommentsBarView (trying to position a small bar with a comments field underneath my tableView).
So in my Document Outline list I have:
view
tableView
comments bar view
UITextView
UILabel
Custom class for "comments bar view" is CommentsBarView.
I have outlets connected from within CommentsBarView to the textfield and label.
(and from the ViewController to the tableView).
When I load my with controller with:
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
I can access the tableView property and change the appearance of the tableVIew, however, from my commentsBarView initWithCoder I can not set the text value on my textView and label:
- (id) initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
if (self) {
[self.commentTextView setText:#"Helo, World!"];
[self.characterCountLabel setText:#"200"];
}
return self;
}
It seems as if these properties are not available at initWithCoder time.
If I manually, from my controllers initWithNibName, accesses self.commentsBar.label.text = 200, there is no problem.
Am I experiencing a timing issue where the views are not ready yet or can I not nest a view inside a viewControllers view and have it backed by a custom UIView subclass?
IB is confusing me a bit.
Thanks for any help given.
When loading from a XIB file, the IBOutlets are not ready in the init methods of the objects being unarchived.
You need to override awakeFromNib in your CommentsBarView to have access to the ready and connected IBOutlets.
Once you get used to IB it becomes better. Since Cocoa is a MVC (Model-View-Controller) you should probably not create a UIView subclass and set your UIView to it. You should probably put the UIView back to just a UIView. I generally subclass a UIView if I need to have a customized look. For example; a good time to subclass a UIView is if you want it to have a gradient. Then you can reuse your subclass for any UIView you wish to show the gradient.
In your case you are trying to "control" the UITextView and UILabel. You can instead wire-up outlets of your UITextView and UILabel directly to your UIViewController (File Owner). That is the "controller" of the MVC in this case. Think of your UIView as a container that is simply holding the two controls for this example. Now you can use the viewDidLoad method or some other method of you UIViewController to set the values of you UITextView and UILabel. It is generally the UIVeiwController that interprets the data from the Model in Cocoa and places the data where it needs to be. It is not a rock-solid rule, but a good one.
Related
I have a simple UIView subclass where I place a UILabel within, in order to give such UIView a certain frame, background color and text format for its label from a UIViewController.
I'm reading the View Programming Guide for iOS but there are some things that I'm not fully understanding... when your view has only system standard subviews, such my UILabel, should I override the drawRect: method? Or is that only intended for Core Animation staff? If I shouldn't setup standard subviews within such method, what is the correct place to do so? Should I then override the init method?
Thanks in advance
No, you should not override the drawRect for initializing the sub views because it causes a performance hit. That should be done either in the init, initWithFrame, or initWithCoder methods. For example, this is how you do it using the initWithFrame method
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
//initialize sub views
}
return self;
How can a subview access the methods from its superview? I have a button, and when pressed I would like the button to call a method from its superview, but I do not know how.
suppose your super View class name is
MainView.h
sub View Name
SubView.h
So In sub class you can do
MainView *myMainView = (Mainview *)[self superview];
[myMainView someMethod];
Make sure someMethod is public Method.
Other way you could have reference to all the view is set a tag
For example
myMainView.tag = 100; or self.tag = 100;
In the subview you could do
MainView *myMainView = (Mainview *)[self viewWithTag:100];
[myMainView someMethod];
a weird construct but just call the method:
inside a view you have have self.superview
since self.superview is a UIView*, the compiler will claim it is invalid to call method XYZ on it. Cast it to id or to your class name to use it
e.g.
[(id)self.superview myMethod];
or even
id myValue = [(id)self.superview myMethod:param1];
One method is to use delegates.
#protocol ButtonHandlingDelegate <NSObject>
- (void) subviewButtonWasPressed;
#end
In your Subview add this:
#property (nonatomic, weak) id selectionDelegate;
When subview is created, set delegate to superview.
Define Superview as delegate in .h file
#interface SuperView : UIView <ButtonHandlingDelegate>
in Superview .m file
- (void) subviewButtonWasPressed{
// Do somethign about it
}
All of the answers listed are hacky and bad style. You should be using delegation through the subview's ViewController. What you will want to do is create a protocol for your subview with a void method called something like specialButtonPressedOnView:(SUBVIEWCLASS *)view. Then in the subview's view controller you should make yourself the delegate for this protocol and respond to the delegate method from the VC's context.
Using self.superview is a bad idea because you cannot guarantee what your superview is going to be and generally blindly calling method on objects (ESPECIALLY those cast to id) is a really bad idea.
The other answer that suggested having the superview implement the subview's protocol is also not good style because you're creating a dependency between your views. If you were thinking of going down this path your subview should probably just be a subclass of the superview.
One of the core parts of the MVC design pattern is making sure that your views are reusable and totally independent. They are just structures that you can inject your content into, to which they will respond with pretty UI, and they don't need to know anything about what's being passed to them and don't have to ask other views for help. So either using delegation through the subview's ViewController or subclassing is probably the best direction. Both methods preserve the MVC pattern and are much safer than the other suggestions.
I'm trying to add a tableview as subview to my tableViewController, but I want to setup the cells in storyboard. It will be a static tableview.
This is the code for calling the tableview on button click.
- (IBAction)botaoAdicionar:(id)sender {
AtividadesPraticadasTableView *tableview = [[AtividadesPraticadasTableView alloc] initWithFrame:CGRectMake(0, 170, 320, 320) style:UITableViewStylePlain];
[self.view addSubview:tableview];
}
In the tableview class I have this:
#implementation AtividadesPraticadasTableView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
Now, I have a viewcontrollerin storyboard with a tableview, which the class of the tableviewI changed to this file AtividadesPraticadasTableView. It has three static custom cells in storyboard, therefore it opens a blank default tableview.
What am I missing?
Static table views are entirely contained within the storyboard, and require information from the storyboard to display their content.
You've defined a static table view controller in the storyboard, populated it and set the tableView's custom class to your custom class, but when you want to add the table view you are just instantiating a table view of that class. That isn't going to get any of the information you've added to the storyboard.
In addition, the static cells information is read and understood by the UITableViewController, not the UITableView, so you are at the wrong level there too.
You need to do the following:
Get a reference to the storyboard, either from your original view controller's storyboard property (if it is on the same storyboard as your static table) or using storyboardWithName:bundle:.
instantiate the table view controller from that storyboard, using instantiateViewControllerWithIdentifier:. This will create a table view controller object containing all your static cells
Add this as a child view controller to your original view controller, using addChildViewController:
Add the table view controller's tableView as a subview
It may be simpler to add a container view in the storyboard to hold this view, and reveal it when the button is pressed, as Mike Slutsky suggested - this will do all of the instantiating and adding and child view controller-ing work for you, but the principle is still the same.
Also, adding a table view as a subview to a table view controller sounds very dodgy - a table view controller already has a table view as its view, and you can't really add subviews to that.
The thing your missing is the association between the programatically instantiated tableview and the UITableView that you put in your storyboard. You cannot just draw UITableViews in your storyboard and start instantiating new UITableViews in the controller's code and expect xcode to know which UITableView you wanted to use from the storyboard. Use an IBOutlet to connect a global variable for the controller to the UITableView in the storyboard, then the controller will know what you're trying to refer to. If you want that UITableView to appear on a button click, simply set the UITableView to hidden by default in the storyboard and then unhide it when the button is pressed.
The thing You are missing called manual. Check this protocol for TableView dataSource https://developer.apple.com/library/ios/documentation/uikit/reference/UITableViewDataSource_Protocol/Reference/Reference.html#//apple_ref/occ/intf/UITableViewDataSource
P.S. Here good tutorial for storyboards http://maniacdev.com/ios-5-sdk-tutorial-and-guide/xcode-4-storyboard
I have a UIViewController say viewControllerA which contains some view element like UIButton, UILabel etc. Now my question is should I create those view elements in a separate UIView class and then add in UIViewController, or should I create those view elements directly inside the UIViewController. Accordingly to MVC isn't it appropriate to create view elements inside a separate UIView class and then add this in UIViewController?
The standard place to build the view hierarchy in a UIViewController is in the -viewDidLoad method. That method gets called whenever the UIViewController's view is created. The view controller's view will be loaded from the NIB/Storyboard if applicable; your outlets will be wired up; and then -viewDidLoad is called for you to perform further customization:
- (void)viewDidLoad
{
[super viewDidLoad];
UILabel *aLabel = [[UILabel alloc] initWithFrame:CGRectMake(0.0,0.0,100.0,40.0)];
[self.view addSubView:aLabel];
}
In Cocoa/Cocoa Touch you don't always want to subclass everything the way you would in, say, Java. There are often other preferred means of extending the functionality in built-in classes such as Objective-C categories, delegation, and pre-defined properties.
It's certainly possible to do this sort of thing another way, but this is the most "Cocoa-like" way to do it. Actually, the most "Cocoa-like" way would be to create the view hierarchy in Interface Builder, but if you want to do it programmatically this is the usual way.
I want to show my own custom UIView in storyboard. By far I have done following but my custom view is not showing up.
Dragged and dropped a UIView instance in my screen.
Defined the class for this UIView as my custom class.
Have connected this UIView with an IBOutlet in my view controller.
I even tried with below code in viewWillAppear.
self.myView = [[MyCustomView alloc] initWithFrame:frame];
This works if I create an instance of my custom view and add as a subview to my IBOutlet property for my view. So, below code is working but I want to keep track of only my IBOutlet iVar and do not want to play with another object for changes on my custom view:
self.myExtraView = [[MyCustomView alloc] initWithFrame:frame];
[self.myView addSubview:self.myExtraView];
Any idea how to do this in a better way so that I could have just one reference of my custom view and could change properties on it as per will.
Found the issue. With storyboard we must initialize anything in initWithCode method. I was implementing the regular init method.