UIView with a Dashed line
calayer, ios, iphone, quartz-2d, uiview
Solution
Note: The code from Prince did really help me out, so I will give him +10 for the tips. But in the end, I add to come with my own code. I will also add some context to it, so it can be useful for future readers
The final code was like this:
-(void)updateLine{
// Important, otherwise we will be adding multiple sub layers
if ([[[self layer] sublayers] objectAtIndex:0])
{
self.layer.sublayers = nil;
}
CAShapeLayer *shapeLayer = [CAShapeLayer layer];
[shapeLayer setBounds:self.bounds];
[shapeLayer setPosition:self.center];
[shapeLayer setFillColor:[[UIColor clearColor] CGColor]];
[shapeLayer setStrokeColor:[[UIColor blackColor] CGColor]];
[shapeLayer setLineWidth:3.0f];
[shapeLayer setLineJoin:kCALineJoinRound];
[shapeLayer setLineDashPattern:
[NSArray arrayWithObjects:[NSNumber numberWithInt:10],
[NSNumber numberWithInt:5],nil]];
// Setup the path
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, beginPoint.center.x, beginPoint.center.y);
CGPathAddLineToPoint(path, NULL, endPoint.center.x, endPoint.center.y);
[shapeLayer setPath:path];
CGPathRelease(path);
[[self layer] addSublayer:shapeLayer];
}
In my case, the beginPoint and endPoint are movable by the user, by using KVO. So when one of them moves:
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
if ([keyPath isEqual:@"position"])
{
[self updateLine];
}
}
I did play a lot with Prince's code. I tried on the `draw:` method, which add a thin line between the dashed line (a bit weird...) and I also tried on `initWithFrame:`. By itself his code, without any modifications, would give me this kind of errors on the console:
<Error>: CGContextSaveGState: invalid context 0x0
<Error>: CGContextSetLineWidth: invalid context 0x0
<Error>: CGContextSetLineJoin: invalid context 0x0
<Error>: CGContextSetLineCap: invalid context 0x0
<Error>: CGContextSetMiterLimit: invalid context 0x0
<Error>: CGContextSetFlatness: invalid context 0x0
<Error>: CGContextAddPath: invalid context 0x0
<Error>: CGContextDrawPath: invalid context 0x0
<Error>: CGContextRestoreGState: invalid context 0x0
Problem
What I have: To create this line, I basically have an `UIView` and I do the following: ``` void setLayerToLineFromAToB(CALayer *layer, CGPoint a, CGPoint b, CGFloat lineWidth) { CGPoint center = { 0.5 * (a.x + b.x), 0.5 * (a.y + b.y) }; CGFloat length = sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y)); CGFloat angle = atan2(a.y - b.y, a.x - b.x); layer.position = center; layer.bounds = (CGRect) { {0, 0}, { length + lineWidth, lineWidth } }; layer.transform = CATransform3DMakeRotation(angle, 0, 0, 1); } ``` Note: This code was found here on stackoverflow, so if someone can give me the reference to it I would appreciate. What I want: Ok so the "only" thing I need is to create this pattern on the `UIView`. I know I am able to do this using Quartz2D (a simple way to do it can be found here). But I want to do it by manipulating the `CALayer` and not going to to the draw method. Why? Because of the transformation I am making on my `UIView`, I am not able to draw correctly using the `draw` method. Edit 1: Just to illustrate my problem: Normally what you have is `UIView` and then you basically just draw something in it (in this case a simple line). The solution I found to get rid of the "gray" area, was to instead of drawing something, just transform the `UIView` itself. It work well, if you want a fully filled line, the problem comes when you want a dashed one.