无限旋转

废话不多说，直接上代码

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    button.frame = CGRectMake(60, 10, 222, 66);
    [button setTitle:@"点我" forState:UIControlStateNormal];
    [button addTarget:self action:@selector(clickTest:) forControlEvents:UIControlEventTouchUpInside];
    button.backgroundColor=[UIColor orangeColor];
    [self.view addSubview:button];
    
    _imgV=[[UIImageView alloc]initWithFrame:CGRectMake(60, button.bottom+40, WIDTH-120, WIDTH-120)];
    _imgV.image=[UIImage imageNamed:@"mohuImage.png"];
    _imgV.contentMode=UIViewContentModeScaleAspectFill;
    _imgV.layer.masksToBounds=YES;
    _imgV.layer.cornerRadius=(WIDTH-120)/2.0;
    [self.view addSubview:_imgV];
    
    [_imgV.layer removeAnimationForKey:@"rotation"];
    CABasicAnimation *animation = [[CABasicAnimation alloc] init];
    animation.fromValue = @(0);
    animation.toValue = @(M_PI * 2);
    animation.duration = 6;
    animation.keyPath = @"transform.rotation.z";
    animation.repeatCount = NSIntegerMax;
    animation.removedOnCompletion = NO;
    [_imgV.layer addAnimation:animation forKey:@"rotation"];

- (void)clickTest:(UIButton*)button {
    if (button.selected) {
        [self resumeAnimate];
    }else {
        [self pauseAnimate];
    }
    button.selected=!button.selected;
}

- (void)pauseAnimate
{
    CFTimeInterval pausedTime = [_imgV.layer convertTime:CACurrentMediaTime() fromLayer:nil];
    _imgV.layer.speed = 0.0;
    _imgV.layer.timeOffset = pausedTime;
}

- (void)resumeAnimate
{
    CFTimeInterval pausedTime = [_imgV.layer timeOffset];
    _imgV.layer.speed = 1.0;
    _imgV.layer.timeOffset = 0.0;
    _imgV.layer.beginTime = 0.0;
    CFTimeInterval timeSincePause = [_imgV.layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;
    _imgV.layer.beginTime = timeSincePause;
}