Question

我有一个动画片，它是一个按照计时器在屏幕上移动的动画，每次敲击时都会缩短。我的问题是动画只播放一次。我尝试调用动画重置并再次开始吧，但没有任何反应。这是一些代码：

-(IBAction)targetTapped:(id)sender {
    [Time invalidate];

    targX = arc4random() %619;
    targY = arc4random() %925;

    NSLog([NSString stringWithFormat:@"X = %li", (long)targX]);
    NSLog([NSString stringWithFormat:@"Y = %li", (long)targY]);

    Target.center = CGPointMake(targX, targY);

    Score = Score + 1;

    if (Score >= 225) {
        timeMax = 0.5;
    }
    else {
        timeMax = 5 - (Score * 0.02);
    }

    Time = [NSTimer scheduledTimerWithTimeInterval:timeMax target:self selector:@selector(Lose) userInfo:nil repeats:NO];

    UIBezierPath *path = [UIBezierPath bezierPath];
    [path moveToPoint:CGPointMake(0.0,895.0)];
    [path addLineToPoint:CGPointMake(768.0, 895.0)];

    CAShapeLayer *pathLayer = [CAShapeLayer layer];
    pathLayer.frame = self.view.bounds;
    pathLayer.path = path.CGPath;
    pathLayer.strokeColor = [[UIColor blueColor] CGColor];
    pathLayer.fillColor = nil;
    pathLayer.lineWidth = 5.0f;
    pathLayer.lineJoin = kCALineJoinBevel;

    [self.view.layer addSublayer:pathLayer];

    CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    pathAnimation.duration = timeMax;
    pathAnimation.fromValue = [NSNumber numberWithFloat:0.0f];
    pathAnimation.toValue = [NSNumber numberWithFloat:1.0f];
    [pathLayer animationForKey:@"strokeEnd"];
    [pathLayer addAnimation:pathAnimation forKey:@"strokeEnd"];
}

Answer 1

您可以创建一次pathLayer：

[self.pathLayer removeAnimationForKey:@"strokeEnd"];

if (self.pathLayer == nil) {
    UIBezierPath *path = [UIBezierPath bezierPath];
    [path moveToPoint:CGPointMake(0.0,895.0)];
    [path addLineToPoint:CGPointMake(768.0, 895.0)];
    CAShapeLayer *pathLayer = [CAShapeLayer layer];
    pathLayer.frame = self.view.bounds;
    pathLayer.path = path.CGPath;
    pathLayer.strokeColor = [[UIColor blueColor] CGColor];
    pathLayer.fillColor = nil;
    pathLayer.lineWidth = 5.0f;
    pathLayer.lineJoin = kCALineJoinBevel;

    [self.view.layer addSublayer:pathLayer];

    self.pathLayer = pathLayer;
}

CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
pathAnimation.duration = timeMax;
pathAnimation.fromValue = [NSNumber numberWithFloat:0.0f];
pathAnimation.toValue = [NSNumber numberWithFloat:1.0f];
[self.pathLayer addAnimation:pathAnimation forKey:@"strokeEnd"];

如何重置CABasicAnimation？

1 个答案: