My code is working so far but I had to create a Class for the UIView. This is a bit inconvenient because I need to interact with the ViewController too.
BTW, I did try [self setNeedsDisplay] on the ViewDidLoad of the UIViewController subclass file but it didn't work.
Here's the code, which works on UIView Subclass but doesn't get called on a UIViewController one:
- (void)drawRect:(CGRect)rect
{
UIColor *currentColor = [UIColor redColor];
CGContextRef context = UIGraphicsGetCurrentContext();
someNum = 1;
CGContextBeginPath(context);
CGContextMoveToPoint(context, 30, 40);
[self addDotImageX:30 andY:40];
CGContextSetLineWidth(context, 2);
CGContextSetStrokeColorWithColor(context, currentColor.CGColor);
CGContextStrokePath(context);
}
Any ideas on what to try? BTW, this is a TabBar App. I know those can somehow block the calls to drawRect.
The Tabs where created programatically, not through a Nib. Eg:
NSMutableArray *listOfViewControllers = [[NSMutableArray alloc] init];
UIViewController *vc;
vc = [[Education alloc] init];
vc.title = #"Education";
[listOfViewControllers addObject:vc];
vc.tabBarItem.image = [UIImage imageNamed:#"info.png"];
[vc release];
I would appreciate any ideas. I've been through the answers on this site related to setNeedsDisplay not calling drawRect and haven't found an answer for my particular case.
Thanks.
You are mixing up two classes. A UIViewController is not a UIView, meaning it doesn't inherits from UIView. But the good news is it has a view, declared as property: It's composition. The drawRect method is only available in a UIView class/subclass.
If you like to force the controller's view to redraw you can call
[self.view setNeedsDisplay];
in the viewController.
You can set your own custom view as the view of your viewController with the loadView method. It could look like this:
- (void)loadView
{
MySubclassOfUIView *rootView = [[MySubclassOfUIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// do more view configuration ...
self.view = rootView;
[rootView release];
}
So you can keep your drawing code separated in your MySubclassOFUIView.m file.
About the UIViewController:
The UIViewController class provides
the fundamental view-management model
for iPhone applications. The basic
view controller class supports the
presentation of an associated view,
support for managing modal views, and
support for rotating views in response
to device orientation changes.
And the purpose of a UIView:
The UIView class defines a rectangular
area on the screen and the interfaces
for managing the content in that area.
At runtime, a view object handles the
rendering of any content in its area
and also handles any interactions with
that content.
Have a look at Cocoa Core Competencies / Model-View-Controller in Apple's official documentation, it describes the MVC design pattern.
You can't override drawRect in a UIViewController, because UIViewController doesn't have a drawRect method.
As I understand, you're making some custom drawing, so it's ok for you to subclass UIView (though if you can have the same results without doing so, it's better). But then if you want to control its behavior, then you should subclass UIViewController.
Make sure you understand how MVC works!
Set your class's class which has been inherited from UIViewController in the interface builder
class which is inherited from UIView and don't override the -drawRect: method in the class which has been inherited from UIViewController. Define the -drawRect: method in the class which has been subclassed from UIView.
Related
Simple question about inheritance
I have a standard program with a master view:
MasterViewController.h
enter code here#interface MasterViewController : UIViewController
using a subview for drawing:
MasterViewController.m
frame = CGRectMake(xo, yo, side*width, side*height); // maxSide
backView = [[BackView alloc] initWithFrame:frame];
[backView setBackgroundColor:[UIColor whiteColor]];
[self infoToBackView];
[self.view addSubview:backView];
BackView.h
#interface BackView : UIView
and BackView.m has its drawRect:
- (void)drawRect {
:
:
}
The problem I have is that I want BackView to inherit from MasterViewController, i.e. I want
Backview.h to be
#interface BackView : MasterViewController
which allows it to inherit the variables it needs from MasterViewController.
The problem is that this does not work; BackView must inherit from UIView to be able to draw with DrawRect. Therefore, before calling the UIView BackView, I must send it the variables it needs for drawing:
[self infoToBackView];
[backView setNeedsDisplay];
where infoToBackView is a method sending the needed variables to BackView.
The $64,000 question: How can I have a BackView that inherits from MasterViewController AND has drawRect?
BackView is a View, it is design to DRAW something.
ViewController are design to manage a view Herarchy.
They are not the same things. One is a plane, the other is an aiport! You cannot fly an airport...
UIView's subclass are design to draw. If you want to draw (text, shapes..) on screen, create a subclass of UIView. If you want to manage a scene in your app storyboard, create a subclass of UIViewController.
drawRect: is a method of UIView
Now you can pass variable to your view from your viewController, like a label (another kind of View) received a text to know what to display.
For example in your ViewController, you can have:
self.myBackView.color = [UIColor blueColor];
self.myBackView.progress = .5;
self.myBackView.text = #"MVC is awesome";
For a better understanding of the MVC design pattern, please reffer to Apple doc : https://developer.apple.com/library/mac/documentation/General/Conceptual/DevPedia-CocoaCore/MVC.html
Is there any way that I can add uiview as a subview over a view controller using UIStoryboard, using xib's we can do that, but i'm unable do that using storyboard.
My storyboard is not holding any of the uiview as a subview when I drag and drop on it, it was placing under the view controller.
Is there any way that I can add it programmatically on my view controller using storyboard.? I'm stuck please help me out
Am I right, you want to hold UIView in storyboards without view controller or superview ?
You can't do that. You should use XIBs to hold custom views.
It doesn't matter you add it programmatically or via drag and drop, in storyboards you can't hold "isolated" views, every view must have a superview and therefore a UIViewController.
Check apple's guide, make sure you understand UIViewController,UIView,UIStoryboard classes and relations between them. Also this.
Hope it helped.
Yes, you can override UIViewController's loadView method to do it as i have written code below.
Because loadView is the method which is called first of all other viewController's loading methods. So you can set it here.
Hope this will work for you as I have tested it on my code.
- (void)loadView {
self.view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, [UIScreen mainScreen].bounds.size.height)];
self.view.backgroundColor = [UIColor blackColor];
// enter your customization code here
}
write this line in function
-(void) ViewDidLoad:
[self.view addSubView:...];
I set an image like this to my view:
self.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"map3.jpg"]];
Right now I have it in a button action method. But how do I make it set directly when the app is launched?
If you want to set the backgroundColor of a UIViewController's view, then move your code into viewDidLoad and adapt likewise:
self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"map3.jpg"]];
A UIViewController doesn't have a backgroundColor directly, but its view does, like any other UIView.
One way is to put that logic within your view controller's -viewDidLoad method for the UIImageView property.
UIView
If you are in a UIView class place the code in either initWithFrame: or initWithCoder:
initWithFrame gets called when you instantiate the view from code (e.g. UIView *myView = [[UIView alloc] initWithFrame:CGRectZero];
initWithCoder: gets called whenever the UIView is loaded from an XIB file.
http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html
UIViewController
If in a UIViewController a common place to put it would be in viewDidLoad
http://developer.apple.com/library/ios/#documentation/uikit/reference/UIViewController_Class/Reference/Reference.html
I am building a cocoa application with one main window controller with a xib. That xib contains many custom view classes. I would like to add an NSViewController to the xib, but i'm running into some trouble.
In interface builder I can drag the NSViewController into the xib, assign it its custom controller class, and assign its view to the appropriate view in the xib. Here's the problem: neither the initWithNibName:Bundle: or loadView get called.
What am I missing?
EDIT:
People seem to be misunderstanding the question so I'll clarify.
The window already has a view controller. What I am seeking to do is assign separate view controllers to several of the subviews. I need to know how to associate my NSViewController subclass with the appropriate NSView subclass (which is a child of the main window).
Or in other words, I am trying to use multiple NSViewController subclasses to controll many different custom views (one each) within a single .xib file. Those controllers and subviews have their own .xibs which should ultimately become visible in the same window.
The pattern I use for NSViewController is to have a xib per view controller. Then, when you need that view controller you alloc it and use the initWithNibName:Bundle: method. As soon as you use its view, loadView will get called.
Example:
self.editViewController = [[[MyEditViewController alloc] initWithNibName:#"MyEditViewController" bundle: nil] autorelease];
[self.window setContentView: editViewController.view];
I used to get stuck with that as well and gave up on that thing - the blue circle with a white bordered view in it from the IB palette. I now create my controllers from code and only set a reference in IB to the owning controller class via the file owner: right click the file owner, enter the class name in the Identity inspector and then make a connection from the file's owner view to the view.
In your code you then do at an appropriate initialisation point:
[self setMyViewController = [[MyViewController alloc] initWithNibName: #"MyView" bundle: [NSBundle mainBundle]]
For your specific case this could be in windowDidLoad method when your window is loaded from its nib and ready for work. You can then add the view to your windows content view. Also you might want to consider to have a 1:1 relation between view and view controller. It makes life a lot easier in terms of maintenance.
EDIT: Like #pcperini suggests in his comments you can use the palette component, but you'll still need to instantiate the controller in your code. If you want to use the palette component, create a property in your main controller or AppDelegate:
#property (...) MyViewController *myViewController;
Add the line of code to actually create the controller (see above). Then, using the bindings inspector bind the palette component to the myViewController property.
So, what you are missing is that you are actually not instantiating the controller object.
EDIT 2: Here's the code (the awakeFromNib is the method of the top controller). It creates two child controllers each handling a different subview:
- (void) awakeFromNib {
[[self startEndTopicHeader] setHeader: #"Event timeline boundary"];
[[self startDateHeaderView] setHeader: #"Event (start) date"];
[[self endDateHeaderView] setHeader: #"Event end date"];
[self setStartDateViewController: [[EventTimeViewController alloc] initWithNibName: #"EventTimeView" bundle: [NSBundle mainBundle]]];
[[[self startDateViewController] view] setFrame: [[self dummyStartView] bounds]];
[[self dummyStartView] addSubview: [[self startDateViewController] view]];
[[self startDateViewController] setParentController: self];
[self setEndDateViewController: [[EventTimeViewController alloc] initWithNibName: #"EventTimeView" bundle: [NSBundle mainBundle]]];
[[[self endDateViewController] view] setFrame: [[self dummyEndView] bounds]];
[[self dummyEndView] addSubview: [[self endDateViewController] view]];
[[self endDateViewController] setParentController: self];
}
I am trying to work my way through basic iPhone programming and I have a good basic understanding of how Interface Builder works, so I decided to try my hand at doing the views programmatically. I have gone through the ViewController Apple guide and searched everywhere and I cannot seem to find a solution to my problem. This leads me to believe it is a very simple solution, but I am just really banging my head against the wall. Basically all I am trying to do is create a view that gets main window as a subview. I know that if self.view is not defined then the loadView method is supposed to be called, and everything is supposed to be set up there. Here is the current state of my code:
The delegate:
- (void)applicationDidFinishLaunching:(UIApplication *)application {
StartMenuViewController *aViewController = [[StartMenuViewController alloc] init];
self.myViewController = aViewController;
[aViewController release];
UIView *controllersView = [myViewController view];
window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
[window setBackgroundColor:[UIColor redColor]];
[window addSubview:controllersView];
[window makeKeyAndVisible];
}
The view controller:
- (id)init {
if (self = [super init]) {
self.title = #"Start Menu";
}
return self;
}
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
UIView *startView = [[UIView alloc] initWithFrame:[UIScreen mainScreen].applicationFrame];
[startView setAutoresizingMask:UIViewAutoresizingFlexibleHeight|UIViewAutoresizingFlexibleWidth];
[startView setBackgroundColor:[UIColor greenColor]];
self.view = startView;
[startView release];
}
Thanks for the help in advance!
Are you sure that you're inheriting from UIViewController and not overriding the implementation of - (UIView*)view?
EDIT: More info:
UIViewController has a special implementation of the "-(UIView*) view" message so that when it's called, the loadView method is called if the view member variable is not set. So, if you provide an implementation of "- (id)view" in your subclass, (or a property named view) it will break the auto-calling of "- loadView".
Just to document a "loadView is not called" case:
I wrote a 2 UITableViewController(s) to handle detail data for a master ViewController. Since the devil was in #2, I made a simple UITableViewController for #1, and referenced it in the XIB for the "master" ViewController.
When I was done with #2, I could simply copy the code to #1, remove the complicated code, and go on with life.
But to my dismay and several days work, no matter what I did, viewLoad was not being called for my simple #1 UITableViewController.
Today I finally realised that I was referencing the UITableViewController in the XIB to the master ViewController program. - and of course, loadView was never being called.
Just to help some other dork that makes the same mistake....
Best Regards,
Charles
viewDidLoad only if the view is unarchived from a nib, method is invoked after view is set.
loadView only invoked when the view proberty is nil. use when creating views programmatically. default: create a UIView object with no subviews.
(void)loadView {
UIView *view = [[UIView alloc] initWithFrame:[UIScreen
mainScreen].applicationFrame];
[view setBackgroundColor:_color];
self.view = view;
[view release];
}
By implementing the loadView method, you hook into the default memory management behavior. If memory is low, a view controller may receive the didReceiveMemoryWarning message. The default implementation checks to see if the view is in use. If its view is not in the view hierarchy and the view controller implements the loadView method, its view is released. Later when the view is needed, the loadView method is invoked
again to create the view.
I would strongly recommend you use interface builder for at least your initial Window/View.
If you create a new project in XCode you should be able to select from one of many pre-defined iPhone templates that come with everything setup.
Unless I am reading this wrong, you did not associate any view with the the controller's view property like this
myViewController.view = controllersView;
So as far as Cocoa is concerned the view you are setting in the window has no controller to call loadView on. loadView is a View controller, not view, method. The view you assign to the window is not associated with any view controller. So your view controller loadView method is never called. Get it? The view you are trying to display, has no view controller associated with it.
When you use interface builder to create views you can link the UIView object you created in IB to the view property in the controller in IB which the framework automatically
But if not done in IB you have to set it