UIButton displaying a square - objective-c

Question

Here is my code to draw my square in my class shape.h (Subclass UIView)
- (void)drawRect:(CGRect)rect
{
//Square
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(context, 2.0);
CGContextSetStrokeColorWithColor(context,
[UIColor blueColor].CGColor);
CGRect rectangle = CGRectMake(20,20,80,80);
CGContextAddRect(context, rectangle);
CGContextStrokePath(context);
}
What i need help with is taking my code and implementing it into a button in my ViewController(h). Saying that whenever i touch the button i would like my square to appear. Im not sure if i'm explaining my self correctly, correct me if im wrong.

Answer 1

I would do it another way:
This is you IBAction that is called, when the button is pressed:
-(IBAction)buttonPressed:(id)sender
{
UIView *square = [[UIView alloc] init];
square.frame = CGRectMake(20, 20, 80, 80);
square.backgroundColor = [UIColor blueColor];
[self.view addSubview:square];
}
This is the IBAction for a circle:
-(IBAction)buttonPressed:(id)sender
{
UIView *circle = [[UIView alloc] init];
circle.frame = CGRectMake(20, 20, 80, 80);
circle.backgroundColor = [UIColor blueColor];
circle.layer.cornerRadius = circle.frame.size.height/2;
[self.view circle];
}
Is that what you wanted? You don't need an extra subclass of UIView for this.
To connect the IBAction to the UIButton, right click in interface builder from the button to this method in code or like this:
[button addTarget:self action:#selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
If you like to draw something more complex (like a triangle) you can subclass UIView. The Code above was for some really easy things. Here is some sample code for a triangle but I think you get the point:
ViewController.m:
#import "ViewController.h"
#import "triangle.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 100, 50)];
[button setTitle:#"Press me" forState:UIControlStateNormal];
button.backgroundColor = [UIColor blackColor];
button.titleLabel.textColor = [UIColor whiteColor];
[button addTarget:self action:#selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:button];
}
-(IBAction)buttonPressed:(id)sender
{
triangle *view = [[triangle alloc] initWithFrame:CGRectMake(0, 80, 200, 200)];
view.backgroundColor = [UIColor whiteColor];
[self.view addSubview:view];
}
#end
triangle.m:
#import "triangle.h"
#implementation triangle
-(void)drawRect:(CGRect)rect
{
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextBeginPath(ctx);
CGContextMoveToPoint (ctx, CGRectGetMinX(rect), CGRectGetMinY(rect)); // top left
CGContextAddLineToPoint(ctx, CGRectGetMaxX(rect), CGRectGetMidY(rect)); // mid right
CGContextAddLineToPoint(ctx, CGRectGetMinX(rect), CGRectGetMaxY(rect)); // bottom left
CGContextClosePath(ctx);
CGContextSetRGBFillColor(ctx, 100/255.f, 100/255.f, 100/255.f, 1);
CGContextFillPath(ctx);
}
#end