CODEWITHSUNDEEP
iosobjective-cxcodecore-graphicsxcode5
barrylachapelle
barrylachapelle

Reputation: 987

Using a custom class (drawrect) on viewController

I am a noob with obj C, and I feel like I am doing everything right so please don't hate me for this ;)...I am trying to make a custom class that draws a rectangle onto a view controller.

So far I have made a class called 'Planet' with the drawrect code. I then added the Planet class (custom class tab) to a view controller on the storyboard. I get no errors but I also get no rectangle.

Planet.h

#import <UIKit/UIKit.h>
@interface Planet : UIViewController
@end

Planet.m

#import "Planet.h"

@implementation Planet

-(void) drawRect:(CGRect)rect{
     CGRect rectangle = CGRectMake(0, 100, 320, 100);
     CGContextRef context = UIGraphicsGetCurrentContext();
     CGContextSetRGBFillColor(context, 1.0, 0.0, 0.0, 1.0);
     CGContextSetRGBStrokeColor(context, 1.0, 0.0, 0.0, 1.0);
     CGContextFillRect(context, rectangle);
}

@end

And a screen of my view controller calling the Planet class.

Xcode screenshot

Outputs...

No error

Upvotes: 0

Views: 823

Answers (4)

bobnoble
bobnoble

Reputation: 5824

Instead of Planet being a subclass of UIViewController, make it a subclass of UIView. The add an instance of Planet to the view of the view controller, maybe in the viewWillAppear method, e.g.:

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];

    Planet *myPlanet = [[Planet alloc] initWithFrame:self.view.frame];
    [self.view addSubview:myPlanet];
}

Upvotes: 0

Prad
Prad

Reputation: 51

use

 [self.view setNeedsDisplay];

in view will appear added subview as planet(UIView).

Upvotes: 0

Greg
Greg

Reputation: 25459

To fix this issue just change the class in storyboard from Planet to what it was previously. Drag a UIView to the view controller and change class for that view to Planet.

You should avoid override of drawRect: if you don't need it because it's very expensive. Instead you should use Layer. You can do something like that to draw rectangle with CALayer:

// Remember to import QuartzCore.h framework
#import <QuartzCore/QuartzCore.h>

CALayer *myLayer = [CALayer layer];
myRect = CGRectMake(0.0f, 0.0f, 150.0f, 200.0f);
[myLayer setBounds:myRect];
[myLayer setBackgroundColor:[[UIColor blackColor] CGColor]];
[myLayer setBorderColor:[[UIColor clearColor] CGColor]];
[myLayer setBorderWidth:1.0f];

//You can change radius
[myLayer setCornerRadius:15.0];
[self.layer addSublayer:myLayer];

It's much less expensive than drawRect:.

Upvotes: 0

santhu
santhu

Reputation: 4792

UIView has drawRect method.Not UIViewController.

UIViewController and UIView both are subclasses of UIResponder. And UIViewController is not a subclass of UIView. And UIView alone has drawRect method.so if you write drawRect in UIViewController, it just thinks its user defined function and won't call it.

If you still have doubt, put a breakpoint in that drawRect function and see whether it is called or not.

Upvotes: 3

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