Updated for Swift 3:
class TriangleView : UIView {
override init(frame: CGRect) {
super.init(frame: frame)
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func draw(_ rect: CGRect) {
guard let context = UIGraphicsGetCurrentContext() else { return }
context.beginPath()
context.move(to: CGPoint(x: rect.minX, y: rect.maxY))
context.addLine(to: CGPoint(x: rect.maxX, y: rect.maxY))
context.addLine(to: CGPoint(x: (rect.maxX / 2.0), y: rect.minY))
context.closePath()
context.setFillColor(red: 1.0, green: 0.5, blue: 0.0, alpha: 0.60)
context.fillPath()
}
}
Swift 2:
import UIKit
class TriangleView : UIView {
override init(frame: CGRect) {
super.init(frame: frame)
}
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func drawRect(rect: CGRect) {
var ctx : CGContextRef = UIGraphicsGetCurrentContext()
CGContextBeginPath(ctx)
CGContextMoveToPoint(ctx, CGRectGetMinX(rect), CGRectGetMaxY(rect))
CGContextAddLineToPoint(ctx, CGRectGetMaxX(rect), CGRectGetMaxY(rect))
CGContextAddLineToPoint(ctx, (CGRectGetMaxX(rect)/2.0), CGRectGetMinY(rect))
CGContextClosePath(ctx)
CGContextSetRGBFillColor(ctx, 1.0, 0.5, 0.0, 0.60);
CGContextFillPath(ctx);
}
}
这将从MinX,MaxY开始
下一部分设置要使用的 colored颜色 .在本例中,255127,0,α0.6
然后在视图控制器中
Swift 3:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let triangle = TriangleView(frame: CGRect(x: 10, y: 20, width: 25 , height: 30))
triangle.backgroundColor = .white
view.addSubview(triangle)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
Swift 2:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let triangle = TriangleView(frame: CGRectMake(10, 20, 25, 30))
triangle.backgroundColor = .whiteColor()
view.addSubview(triangle)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
然而,这将导致同样的问题,因为这个视图的框架仍然是一个矩形.UIKit使用矩形,你必须使用另一个框架,比如Sprite Kit.