问题描述
@property(nonatomic,strong)CADisplayLink *timer;//定时器#pragma mark - lazyInstall-(CAShapeLayer*)shapeLayer { if (!_shapeLayer) {//创建出CAShapeLayerself.shapeLayer = [CAShapeLayer layer];self.shapeLayer.frame = CGRectMake(0, 0, 57, 80);self.shapeLayer.position = self.potrait.center;self.shapeLayer.fillColor = [UIColor clearColor].CGColor;//设置线条的宽度和颜色self.shapeLayer.lineWidth = 2.0f;self.shapeLayer.strokeColor = [UIColor greenColor].CGColor; //创建出圆形贝塞尔曲线UIBezierPath *circlePath = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 57, 80) cornerRadius:3];//让贝塞尔曲线与CAShapeLayer产生联系self.shapeLayer.path = circlePath.CGPath; } return _shapeLayer;}#pragma mark - Timer-(void)startCycle {//用定时器模拟数值输入的情况 [self.layer addSublayer:self.shapeLayer];_shapeLayer.strokeStart = 0; _shapeLayer.strokeEnd = 1; _timer = [CADisplayLink displayLinkWithTarget:self selector:@selector(circleAnimationType)]; _timer.frameInterval = 1; //设置刷新60次响应一次 [_timer addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];}- (void)circleAnimationType {//用定时器调用的方法 if (_shapeLayer.strokeStart != 1) {_shapeLayer.strokeStart += 倒计时时间; }}-(void)endCycle { [_timer invalidate]; _timer = nil;_shapeLayer.strokeStart = 1; _shapeLayer.strokeEnd = 0;// [_timer setFireDate:[NSDate distantFuture]];}
其中-(void)startCycle是开始倒计时方法，-(void)endCycle是结束倒计时方法。经过不断的开始和结束，动画的倒计时时长越来越短，是为什么？？求大神解惑
问题解答
回答1：if(!_timer){
_timer = [CADisplayLink displayLinkWithTarget:self selector:@selector(circleAnimationType)];_timer.frameInterval = 1; //设置刷新60次响应一次[_timer addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
}
