基本思路其实很简单，就是通过贝塞尔曲线画出路径，然后
使用CAShapeLayer 渲染路径，然后通过strokeEnd 动画实现
路径的效果，这里注意，这个过程中过遇到过一个问题，就是
对号动画完成之后，整个对号不见了，后来经过仔细调查，发现，是自己初始化 checkLayer的时候，将strokeEnd属设置为0了，注意，虽然我们是通过"strokeEnd"设置的动画，但是我们进行动画之后，并不会真正的改变layer.strokeEnd属性的值，所以我们初始化对号layer的时候,还是要将strokeEnd设置为1
下面贴出所有代码

//
//  ViewController.m
//  LBProgressCircle
//
//  Created by mac on 2024/5/31.
//#import "ViewController.h"@interface ViewController ()@property (nonatomic, strong) UIView *loadingView;//进度圆环曲线
@property (nonatomic, strong) UIBezierPath *circlePath;
//整个圆环
@property (nonatomic, strong) CAShapeLayer *wholeCircleLayer;
//进度圆环layer
@property (nonatomic, strong) CAShapeLayer *progressLayer;
//对号圆环
@property (nonatomic, strong) CAShapeLayer *checkRoundLayer;
//对号layer
@property (nonatomic, strong) CAShapeLayer *checkLayer;@end@implementation ViewController- (void)viewDidLoad {[super viewDidLoad];self.view.backgroundColor = [UIColor lightGrayColor];[self.view addSubview:self.loadingView];[self.loadingView.layer addSublayer:self.wholeCircleLayer];[self.loadingView.layer addSublayer:self.progressLayer];[self.loadingView.layer addSublayer:self.checkLayer];[self.loadingView.layer addSublayer:self.checkRoundLayer];[self handle];// Do any additional setup after loading the view.
}- (void)handle
{self.progressLayer.strokeEnd = 0;__block CGFloat second = 0;NSTimer *time = [NSTimer scheduledTimerWithTimeInterval:0.1 repeats:YES block:^(NSTimer * _Nonnull timer) {if (second >= 1) {return;}second += 0.1;[self updateProgress:second];}];
}- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{[self handle];
}- (void)updateProgress:(CGFloat)progress
{self.progressLayer.strokeEnd = progress;if (progress >= 1) {[self showProgressCirce:NO];[self.checkRoundLayer addAnimation:[self animation] forKey:@"strokeEnd"];dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{self.checkLayer.hidden = NO;[self.checkLayer addAnimation:[self animation] forKey:@"strokeEnd"];});} else {self.checkLayer.hidden = YES;[self showProgressCirce:YES];}
}- (void)showProgressCirce:(BOOL)showCircle
{self.checkRoundLayer.hidden = showCircle;self.wholeCircleLayer.hidden = !showCircle;self.progressLayer.hidden = !showCircle;
}#pragma mark - lazy load- (UIView *)loadingView
{if (!_loadingView) {_loadingView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];_loadingView.backgroundColor = [UIColor blackColor];}return _loadingView;
}- (UIBezierPath *)circlePath
{if (!_circlePath) {_circlePath = [UIBezierPath bezierPathWithArcCenter:CGPointMake(27.5, 44) radius:19 startAngle:-M_PI_2 endAngle:-M_PI_2 + M_PI * 2 clockwise:YES];_circlePath.lineCapStyle = kCGLineCapRound;_circlePath.lineJoinStyle = kCGLineJoinRound;}return _circlePath;
}- (CAShapeLayer *)progressLayer
{if (!_progressLayer) {_progressLayer = [[CAShapeLayer alloc] init];_progressLayer.path = self.circlePath.CGPath;_progressLayer.strokeStart = 0;_progressLayer.strokeEnd = 0;_progressLayer.strokeColor = [UIColor redColor].CGColor;_progressLayer.fillColor = [UIColor clearColor].CGColor;_progressLayer.lineWidth = 2;}return _progressLayer;
}- (CAShapeLayer *)wholeCircleLayer
{if (!_wholeCircleLayer) {_wholeCircleLayer = [[CAShapeLayer alloc] init];_wholeCircleLayer.path = self.circlePath.CGPath;_wholeCircleLayer.strokeStart = 0;_wholeCircleLayer.strokeEnd = 1;_wholeCircleLayer.strokeColor = [[UIColor redColor] colorWithAlphaComponent:0].CGColor;_wholeCircleLayer.fillColor = [UIColor clearColor].CGColor;_wholeCircleLayer.lineWidth = 2;}return _wholeCircleLayer;
}- (CAShapeLayer *)checkRoundLayer
{if (!_checkRoundLayer) {UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(27.5, 44) radius:16 startAngle:- M_PI_2 endAngle:- M_PI_2 + M_PI * 2 clockwise:YES];path.lineCapStyle = kCGLineCapRound;path.lineJoinStyle = kCGLineJoinRound;_checkRoundLayer = [[CAShapeLayer alloc] init];_checkRoundLayer.path = path.CGPath;_checkRoundLayer.strokeColor = [UIColor whiteColor].CGColor;_checkRoundLayer.fillColor = [UIColor clearColor].CGColor;_checkRoundLayer.hidden = YES;_checkRoundLayer.lineWidth = 2;}return _checkRoundLayer;
}- (CAShapeLayer *)checkLayer
{if (!_checkLayer) {UIBezierPath *path = [[UIBezierPath alloc] init];path.lineCapStyle = kCGLineCapRound;path.lineJoinStyle = kCGLineJoinRound;[path moveToPoint:CGPointMake(19, 43)];CGPoint pl = CGPointMake(25, 49);[path addLineToPoint:pl];CGPoint p2 = CGPointMake(36, 39);[path addLineToPoint:p2];_checkLayer = [[CAShapeLayer alloc] init];_checkLayer.fillColor = [UIColor clearColor].CGColor;//线条颜色_checkLayer.strokeColor = [UIColor whiteColor].CGColor;_checkLayer.lineWidth = 2;_checkLayer.path = path.CGPath;_checkLayer.hidden = YES;}return _checkLayer;
}- (CABasicAnimation *)animation
{CABasicAnimation *checkAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];checkAnimation.duration = 0.5;checkAnimation.fromValue = @(0);checkAnimation.toValue = @(1);return checkAnimation;
}@end