CODEWITHSUNDEEP
iphonexcode
user1217340
user1217340

Reputation: 29

Drawing a circle after button click in xcode

I am trying to draw a circle after clicking a button. I can create a rectangle but cannot draw a circle.

Is there a way to make this:

-(IBAction) buttonTouched 
{
}

call or signal this to work:

- (void)drawRect:(CGRect)rect 
{ 
}

Thanks for any input!

*Edit** Sorry, it's not working. Not sure what I'm doing wrong:

1) Created a new view-based project named "test". 2) Created a Objective-C class UIView named "view". 3) In IB dragged a button onto the view, linked it to "buttonTouched" - Touched Up Inside.

testViewController.h
#import <UIKit/UIKit.h>
#import "view.h"
@interface testViewController : UIViewController {
}
-(IBAction) buttonTouched;
@end


testViewController.m
#import "testViewController.h"
#import "view.h"
@implementation testViewController
- (IBAction)buttonTouched {
    [[self view] setNeedsDisplay];
}

view.m

#import "view.h"

@implementation view

- (id)initWithFrame:(CGRect)frame {    
   self = [super initWithFrame:frame];
    if (self) {
    }
    return self;
}

- (void)drawRect:(CGRect)rect {
    CGContextRef contextRef = UIGraphicsGetCurrentContext();

    CGContextFillEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
    CGContextSetRGBFillColor(contextRef, 0, 0, 255, 1.0);

    CGContextStrokeEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
    CGContextSetRGBFillColor(contextRef, 0, 0, 255, 1.0);
}


- (void)dealloc {
    [super dealloc];
}

@end

Upvotes: 1

Views: 12026

Answers (3)

BDGapps
BDGapps

Reputation: 3356

This should do what you want it to. Check Sample code

     // The color is by this line CGContextSetRGBFillColor( context , red , green , blue , alpha);


     // Draw a circle (filled)
     CGContextFillEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
     CGContextSetRGBFillColor(contextRef, 0, 0, 255, 1.0);

     // Draw a circle (border only)
     CGContextStrokeEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));
     CGContextSetRGBFillColor(contextRef, 0, 0, 255, 1.0);

Upvotes: 6

SachinVsSachin
SachinVsSachin

Reputation: 6427

-(void)drawRect:(CGRect)rect {
    CGContextRef contextRef = UIGraphicsGetCurrentContext();
    CGContextSetRGBFillColor(contextRef, 0, 0, 255, 0.1);
    CGContextSetRGBStrokeColor(contextRef, 0, 0, 255, 0.5);
    // Draw a circle (filled)
    CGContextFillEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));

    // Draw a circle (border only)
    CGContextStrokeEllipseInRect(contextRef, CGRectMake(100, 100, 25, 25));

    // Get the graphics context and clear it
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    CGContextClearRect(ctx, rect);

    // Draw a green solid circle
    CGContextSetRGBFillColor(ctx, 0, 255, 0, 1);
    CGContextFillEllipseInRect(ctx, CGRectMake(100, 100, 25, 25));

    // Draw a yellow hollow rectangle
    CGContextSetRGBStrokeColor(ctx, 255, 255, 0, 1);
    CGContextStrokeRect(ctx, CGRectMake(195, 195, 60, 60));

    // Draw a purple triangle with using lines
    CGContextSetRGBStrokeColor(ctx, 255, 0, 255, 1);
    CGPoint points[6] = { 
        CGPointMake(100, 200), CGPointMake(150, 250),
        CGPointMake(150, 250), CGPointMake(50, 250),
        CGPointMake(50, 250), CGPointMake(100, 200) 
    };
    CGContextStrokeLineSegments(ctx, points, 6);
}

Upvotes: 0

rob mayoff
rob mayoff

Reputation: 385870

If you want the system to call drawRect:, you call setNeedsDisplay:

// In your view controller...
- (IBAction)buttonTouched {
    [self.view setNeedsDisplay];
}

// In your UIView subclass...
- (void)drawRect:(CGRect)rect {
    [UIColor.redColor setFill];
    [[UIBezierPath bezierPathWithOvalInRect:self.bounds] fill];
}

Upvotes: 1

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