iOS开发教程之扇形动画的实现

-(instancetype)initWithCenter:(CGPoint)center radius:(CGFloat)radius bgColor:(UIColor *)bgColor repeatCount:(NSInteger)repeatCount { if (self = [super init]) {  //设置self的frame和center  self.backgroundColor = bgColor;  self.frame = CGRectMake(0, 0, radius * 2, radius * 2);  self.center = center;  _repeatCount = repeatCount;  //特别注意：贝塞尔曲线的radius必须为self高度的四分之一，CAShapeLayer的线宽必须为self高度的二分之一  UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(radius, radius) radius:radius / 2 startAngle:-M_PI/2 endAngle:M_PI *3 / 2 clockwise:YES];  CAShapeLayer *maskLayer = [CAShapeLayer layer];  maskLayer.path = path.CGPath;  maskLayer.fillColor = [UIColor clearColor].CGColor;  maskLayer.strokeColor = bgColor.CGColor;  maskLayer.lineWidth = radius; //等于半径的2倍，以圆的边缘为中心，向圆内部伸展一个半径，向外伸展一个半径，所以看上去以为圆的半径是self高度的一半。  self.layer.mask = maskLayer;  _maskLayer = maskLayer; } return self;}-(void)startAnimaiton { //开始执行扇形动画 CABasicAnimation *strokeEndAni = [CABasicAnimation animationWithKeyPath:@"strokeEnd"]; strokeEndAni.fromValue = @0; strokeEndAni.toValue = @1; strokeEndAni.duration = 1; //重复次数 strokeEndAni.repeatCount = _repeatCount; [_maskLayer addAnimation:strokeEndAni forKey:@"ani"];}

/**初始化对象@param center 中心@param radius self宽度的一半@param bgColor 背景色@param repeatCount 动画重复次数@return self*/-(instancetype)initWithCenter:(CGPoint)center radius:(CGFloat)radius bgColor:(UIColor *)bgColor repeatCount:(NSInteger)repeatCount;-(void)startAnimaiton;-(void)puaseAnimation;