Circular Progress Bar with CAShapeLayer and CABasicAnimation

Question

I am trying to make Circular Progress View using the idea from here

This is my code for the CircleView:

#import "CircleView.h"

@interface CircleView()

@property (nonatomic, strong) CAShapeLayer *circleLayer;

@end

@implementation CircleView

-(instancetype)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];

if (self) {
    self.backgroundColor = UIColor.clearColor;

    UIBezierPath *circlePath = [UIBezierPath bezierPathWithArcCenter:CGPointMake(self.frame.size.width / 2., self.frame.size.height / 2.0) radius: (self.frame.size.width - 10) / 2 startAngle:0.0 endAngle:M_PI * 2 clockwise:YES];

    CAShapeLayer *downLayer = [[CAShapeLayer alloc] init];
    downLayer.path = circlePath.CGPath;
    downLayer.fillColor = UIColor.clearColor.CGColor;
    downLayer.strokeColor = UIColor.lightGrayColor.CGColor;
    downLayer.lineWidth = 10.0;

    downLayer.strokeEnd = 1.0;

    self.circleLayer = [[CAShapeLayer alloc] init];
    self.circleLayer.path = circlePath.CGPath;
    self.circleLayer.fillColor = UIColor.clearColor.CGColor;
    self.circleLayer.strokeColor = UIColor.redColor.CGColor;
    self.circleLayer.lineWidth = 10.0;

    self.circleLayer.strokeEnd = 0.0;

    [self.layer addSublayer:downLayer];
    [self.layer addSublayer: self.circleLayer];
}

return self;
}

-(void)animateCircle:(NSTimeInterval)duration fromPart:(CGFloat)fromPart toPart: (CGFloat)toPart {

CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];

animation.duration = duration;

animation.fromValue = @(fromPart);
animation.toValue = @(toPart);

animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];

self.circleLayer.strokeEnd = toPart;

[self.circleLayer addAnimation:animation forKey:@"animateCircle"];

}

@end

The problem is when I try to make this animation more than once. Then it shows only the animation from the last call and as if the previous calls have already finished animating. For example if I make the following two calls:

[self.circleView animateCircle:1 fromPart:0.0 toPart:0.25];
[self.circleView animateCircle:1 fromPart:0.25 toPart:0.5];

It will show only animating the colouring from 0.25 percentage of the circle to 0.5 percentage of the circle. Can I change that? I need to show all animations one after another. (Need to show the progress of a download)

Answer 1

You need to remove these 2 below lines and it will work as expected.

animation.fromValue = @(fromPart);
animation.toValue = @(toPart);

Because you use CircleView to display progress of a download so your method don't need fromPart value when animating circle. You can update animateCircle method like below code.

-(void)animateCircle:(NSTimeInterval)duration toPart: (CGFloat)toPart {

  CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];

  animation.duration = duration;

  animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];

  self.circleLayer.strokeEnd = toPart;

  [self.circleLayer addAnimation:animation forKey:@"animateCircle"];

}

Result