CODEWITHSUNDEEP
iosuiview
CodeGuy
CodeGuy

Reputation: 28905

Simple UIView drawRect not being called

I can't figure out what the problem is here. I have a very simple UIViewController with a very simple viewDidLoad method:

-(void)viewDidLoad {

    NSLog(@"making game view");
    GameView *v = [[GameView alloc] initWithFrame:CGRectMake(0,0,320,460)];

    [self.view addSubview:v];

    [super viewDidLoad];
}

And my GameView is initialized as follows:

@interface GameView : UIView {

and it simply has a new drawRect method:

- (void)drawRect:(CGRect)rect
{

    [super drawRect:rect];

    NSLog(@"drawing");
}

In my console, I see "making game view" being printed, but "drawing" never is printed. Why? Why isn't my drawRect method in my custom UIView being called. I'm literally just trying to draw a circle on the screen.

Upvotes: 7

Views: 11830

Answers (4)

jtf
jtf

Reputation: 125

I had a view that was offscreen, that I would load onscreen and then redraw. However, while cleaning up auto-layout constraints in XCode, it decided my offscreen view should have a frame (0,0,0,0) (x,y,w,h). And with a (0,0) size, the view would never load.

Make sure your NSView has a nonzero frame size, or else drawRect will not be called.

Upvotes: 0

Zack Weiner
Zack Weiner

Reputation: 674

If you're using a CocoaTouch lib or file you may need to override the initWithCoder method instead of viewDidLoad.

Objective-C:

- (instancetype)initWithCoder:(NSCoder *)coder
{
    self = [super initWithCoder:coder];
    if (self) {
        //Do Stuff Here
    }
    return self;
}

Upvotes: 0

Newbie indeed
Newbie indeed

Reputation: 87

Check if your view is being displayed. If a view is not currently on screen, drawRect will not be getting called even if you add the view to its superview. A possibility is that your view is blocked by the some other view.

And as far as I know, you don't need to write [super drawRect];

Note that even if viewDidLoad is called on a view controller it doesn't necessarily indicate the view controller's view is displayed on screen. Example: Assume a view controller A has an ivar where a view controller B is stored and view controller A's view is currently displayed. Also assume B is alloced and inited. Now if some method in A causes B's view to be accessed viewDidLoad in B will be called as a result regardless whether it's displayed.

Upvotes: 0

Eytan
Eytan

Reputation: 1835

Have you tried specifying the frame in the initialization of the view? Because you are creating a custom UIView, you need to specify the frame for the view before the drawing method is called.

Try changing your viewDidLoad to the following:

NSLog(@"making game view");
GameView *v = [[GameView alloc] initWithFrame:CGRectMake(0,0,320,460)];


if (v == nil)
    NSLog(@"was not allocated and/or initialized");

[self.view addSubview:v];

if (v.superview == nil)
    NSLog(@"was not added to view");

[super viewDidLoad];

let me know what you get.

Upvotes: 12

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