iPhone CALayer animation

Question

I am drawing a line animation, connecting 2 points with a line. This is my code:

-(void) drawObject{     
    rootLayer   = [CALayer layer];
    rootLayer.frame = self.view.bounds;
    [self.view.layer addSublayer:rootLayer];

    lineStartPath = CGPathCreateMutable();
    CGPathMoveToPoint(lineStartPath, nil, 160, 50);
    CGPathAddLineToPoint(lineStartPath, nil, 160, 50);
    CGPathCloseSubpath(lineStartPath);

    lineEndPath = CGPathCreateMutable();
    CGPathMoveToPoint(lineEndPath, nil, 160, 50);
    CGPathAddLineToPoint(lineEndPath, nil, 160, 300);
    CGPathCloseSubpath(lineEndPath);

    shapeLayer = [CAShapeLayer layer];
    shapeLayer.path = lineStartPath;
    UIColor *strokeColor = [UIColor colorWithHue:0.557 saturation:0.55 brightness:0.96 alpha:1.0];
    shapeLayer.strokeColor = strokeColor.CGColor;
    shapeLayer.lineWidth = 3.0;

    [rootLayer addSublayer:shapeLayer];

    [self performSelector:@selector(startAnimation) withObject:nil afterDelay:1.0];
}

-(void) startAnimation{
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"path"];
    animation.duration = 0.5;
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
    animation.fromValue = (id)lineStartPath;
    animation.toValue = (id)lineEndPath;
    [shapeLayer addAnimation:animation forKey:@"animatePath"];
}

The weak point is after the animation is ended, the line disappears. I want that after my line is drawn between those 2 points, id does not disappear. Give me a hint please.

score 2 · Accepted Answer · edited Jun 09 '19 at 12:29

2

Try adding

shapeLayer.path = lineEndPath;

at the beginning of startAnimation.

It's explained in this video: Session 424 - Core Animation in Practice, Part 1 from the WWDC 2010 (around 38:00).

~~and replace [shapeLayer addAnimation:animation forKey:@"animatePath"]; with [shapeLayer addAnimation:animation forKey:@"path"];.~~

edited Jun 09 '19 at 12:29

Cœur

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answered Feb 21 '11 at 11:14

Jilouc

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The key when you add an animation can be whatever you want, it is only used to get the animation back using `[myLayer animationForKey:@"myKey"];` – David Rönnqvist Jul 13 '12 at 05:58

iPhone CALayer animation

1 Answers1

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