DCAdams DCAdams - 5 months ago 26
Objective-C Question

How do I remove a UIBezierPath drawing?

I'm creating an app where you eventually have to sign, and I was wondering how you would clear the signature if they messed up?

EDIT:

Line Class:

#import "LinearInterpView.h"

@implementation LinearInterpView
{
UIBezierPath *path; // (3)
}

- (id)initWithCoder:(NSCoder *)aDecoder // (1)
{
if (self = [super initWithCoder:aDecoder])
{
self.backgroundColor = UIColor.whiteColor;
[self setMultipleTouchEnabled:NO]; // (2)
[self setBackgroundColor:[UIColor whiteColor]];
path = [UIBezierPath bezierPath];
[path setLineWidth:2.0];
}
return self;
}

- (void)drawRect:(CGRect)rect // (5)
{
[[UIColor blackColor] setStroke];
[path stroke];
}


- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint p = [touch locationInView:self];
[path moveToPoint:p];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint p = [touch locationInView:self];
[path addLineToPoint:p]; // (4)
[self setNeedsDisplay];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
[self touchesMoved:touches withEvent:event];
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
[self touchesEnded:touches withEvent:event];
}

-(void) clearPath{

path = nil;
path = [UIBezierPath bezierPath];
[self setNeedsDisplay];

}

@end


And then in my other class "SecondViewController", I have a button which is connected to the IBAction clearMethod:

-(IBAction)clearMethod:(id)sender{

LinearInterpView *theInstance = [[LinearInterpView alloc] init];
[theInstance clearPath];

}


It contains the Line Class and calls the clearPath Method.

The part that is not working is what is inside of the clearPath function:

-(void) clearPath{

path = nil;
[self setNeedsDisplay];

}

Answer

set the bezierPath to nil which clears the old bezier path! and call [self setNeedsDisplay] on the view where you draw the signature!