UIBezierPath和CABasicAnimation画一条从左至右有动画的线，画曲线

  根据转载文章改写

动态 画从左到右的直线

   UIBezierPath *path = [UIBezierPath bezierPath];
    [path moveToPoint:(CGPointMake(30, 100))];
    [path addLineToPoint:(CGPointMake(300, 100))];
    
    CAShapeLayer *shaperLayer = [CAShapeLayer layer];
//    shaperLayer.frame = CGRectMake(30, 100, 300, 20);
//    shaperLayer.backgroundColor = [UIColor yellowColor].CGColor;
//    shaperLayer.fillColor = [UIColor blueColor].CGColor;
    shaperLayer.path = path.CGPath;
    shaperLayer.strokeColor = [UIColor redColor].CGColor;
    
    
    CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:NSStringFromSelector(@selector(strokeEnd))];
    anim.fromValue = @0;
    anim.toValue = @1;
    anim.duration = 5;
    
    [shaperLayer addAnimation:anim forKey:NSStringFromSelector(@selector(strokeEnd))];
    [self.view.layer addSublayer:shaperLayer];
   

画曲线

    UIBezierPath *path = [UIBezierPath bezierPath];

    [path moveToPoint:CGPointMake(20, 300)];
    [path addQuadCurveToPoint:CGPointMake(300, 300)
                 controlPoint:CGPointMake(100, 100)];

    path.lineCapStyle = kCGLineCapRound;
    path.lineJoinStyle = kCGLineJoinRound;
    path.lineWidth = 5.0;

    
    CAShapeLayer *shaperLayer = [CAShapeLayer layer];
    shaperLayer.path = path.CGPath;
    shaperLayer.strokeColor = [UIColor redColor].CGColor;
    shaperLayer.fillColor = [UIColor yellowColor].CGColor;
    
    
    CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:NSStringFromSelector(@selector(strokeEnd))];
    anim.fromValue = @0;
    anim.toValue = @1;
    anim.duration = 1;
    
    [shaperLayer addAnimation:anim forKey:NSStringFromSelector(@selector(strokeEnd))];
    
    [self.view.layer addSublayer:shaperLayer];

转载文章

//view 是曲线的背景 view

UIView *view = [[ UIView alloc ] initWithFrame : CGRectMake ( 10 , 0 ,300 ,300 )];

    view. backgroundColor = [ UIColor whiteColor];

[ self . view addSubview :view];

// 第一、 UIBezierPath 绘制线段

    UIBezierPath *firstPath = [ UIBezierPath bezierPathWithOvalInRect : CGRectMake (0,0, 5 , 5 )];

CGPoint p1 = CGPointMake ( 0 , 0 );

CGPoint p2 = CGPointMake ( 300 , 0 );

[firstPath addLineToPoint :p1];

[firstPath addLineToPoint :p2];

    UIBezierPath *lastPath = [ UIBezierPath bezierPathWithOvalInRect : CGRectMake (300,0, 0 , 0 )];

[firstPath appendPath :lastPath];

// 第二、 UIBezierPath 和 CAShapeLayer 关联

    CAShapeLayer *lineLayer2 = [ CAShapeLayer layer ];

lineLayer2. frame = CGRectMake ( 0 ,50 ,320 ,40 );

lineLayer2. fillColor = [ UIColor yellowColor ].CGColor ;

lineLayer2. path = firstPath. CGPath ;

    lineLayer2. strokeColor = [ UIColor redColor ]. CGColor ;

//第三，动画

    CABasicAnimation *ani = [ CABasicAnimation animationWithKeyPath : NSStringFromSelector ( @selector (strokeEnd))];

ani. fromValue = @0 ;

ani. toValue = @1 ;

ani. duration = 5 ;

    [lineLayer2 addAnimation :ani forKey : NSStringFromSelector ( @selector (strokeEnd))];

[view. layer addSublayer :lineLayer2];