删除UIBezierPath绘图？

Question

我在致力于数字签名UIView。我通过这段代码创建它，但我无法删除按钮单击时的贝塞尔路径。点击按钮时不会创建新的BezierPath。我分享我的代码，请看我的代码。

 //Create Class for UIView 
     #import "SignView.h" 
     { 
      UIBezierPath *path; 
     } 
     - (id)initWithCoder:(NSCoder *)aDecoder 
     { 
      if (self = [super initWithCoder:aDecoder]) 
      { 
       [self setMultipleTouchEnabled:NO]; 
       [self setBackgroundColor:[UIColor whiteColor]]; 
       path = [UIBezierPath bezierPath]; 
       [path setLineWidth:2.0]; 
      } 
      return self; 
     } 

     - (void)drawRect:(CGRect)rect 
     { 
      [[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]; 
      [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)erase 
     { 
      path = nil; 
      path = [UIBezierPath bezierPath]; 
      [path setLineWidth:2.0]; 
      [self setNeedsDisplay]; 

     } 

     //viewController.m 

     - (IBAction)clearSign:(id)sender { 
      SignView *clrView = [[SignView alloc]init]; 
      [clrView erase]; 
     } 

Answer 1

请更改擦除方法如下：

- (void)erase 
     { 
      [path removeAllPoints]; 
      path = [UIBezierPath bezierPath]; 
      [path setLineWidth:2.0]; 
      [self setNeedsDisplay]; 

     } 

要删除功能工作，你可以在下面使用appocahes：

方法1

如果您正在通过代码使用t加载符号视图他下面的代码：

//ViewController.m 

    #import "SignView.h " 

    @interface MySignatureViewController : UIViewController { 
     SignView* signView; 
    } 

    -(void)viewDidLoad{ 
     signView= [[ mySmoothLineView alloc] initWithFrame: desiredFrame]; 
     [signView setBackgroundColor:[UIColor clearColor]]; 
     [self.view addSubview: signView]; 
    } 

    - (IBAction)clearSign:(id)sender { 
       [signView erase]; 
      } 

方法2

如果您使用的故事板

//ViewController.m 


     #import "SignView.h " 

     @interface MySignatureViewController : UIViewController { 
      @property (nonatomic, weak)SignView* signView; 
     } 



     - (IBAction)clearSign:(id)sender { 
        [self.signView erase]; 
       }