ios - 我如何在单击按钮时从 uiview 中删除 UIBezierPath。？

Question

我正在 uiview 上进行数字签名。我通过此代码正常创建它，但我无法在单击按钮时删除贝塞尔曲线路径。我正在分享我的代码请查看我的代码。

#import "Signature.h"

 @implementation Signature {
UIBezierPath *path;
UIImage *incrementalImage;
CGPoint pts[5]; // we now need to keep track of the four points of a Bezier segment and the first control point of the next segment
uint ctr;
  }

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

  }

   - (id)initWithFrame:(CGRect)frame
 {
self = [super initWithFrame:frame];
if (self) {
    [self setMultipleTouchEnabled:NO];
    path = [UIBezierPath bezierPath];
    [path setLineWidth:2.0];
}
return self;
   }

 - (void)drawRect:(CGRect)rect
    {
[incrementalImage drawInRect:rect];
[path stroke];
 }

    - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
  {
ctr = 0;
UITouch *touch = [touches anyObject];
pts[0] = [touch locationInView:self];
   }

    - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
      {
UITouch *touch = [touches anyObject];
CGPoint p = [touch locationInView:self];
ctr++;
pts[ctr] = p;
if (ctr == 4)
{
    pts[3] = CGPointMake((pts[2].x + pts[4].x)/2.0, (pts[2].y + pts[4].y)/2.0); // move the endpoint to the middle of the line joining the second control point of the first Bezier segment and the first control point of the second Bezier segment

    [path moveToPoint:pts[0]];
    [path addCurveToPoint:pts[3] controlPoint1:pts[1] controlPoint2:pts[2]]; // add a cubic Bezier from pt[0] to pt[3], with control points pt[1] and pt[2]

    [self setNeedsDisplay];
    // replace points and get ready to handle the next segment
    pts[0] = pts[3];
    pts[1] = pts[4];
    ctr = 1;
}
      }

   - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
   {
[self drawBitmap];
[self setNeedsDisplay];
[path removeAllPoints];
ctr = 0;
  }

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

    - (void)drawBitmap
      {
UIGraphicsBeginImageContextWithOptions(self.bounds.size, YES, 0.0);

if (!incrementalImage) // first time; paint background white
{
    UIBezierPath *rectpath = [UIBezierPath bezierPathWithRect:self.bounds];
    [[UIColor greenColor] setFill];
    [rectpath fill];
}
[incrementalImage drawAtPoint:CGPointZero];
[[UIColor blackColor] setStroke];
[path stroke];
incrementalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
    }

    - (void)erase {
NSLog(@"Erase Testing...");
 // self->path   = nil;  //Set current path nil
 //path   = [UIBezierPath bezierPath];
// [self setNeedsDisplay];
  }

我在另一个类的取消按钮单击上调用了删除方法，但我无法删除 uibezeripath。

Answer 1

尝试使用它来删除 UIBezierPath，

[path removeAllPoints];

如果你使用 CAShapeLayer *rectLayer = [[CAShapeLayer alloc] init]; 那么也调用这一行，

[rectLayer removeFromSuperlayer];