如何改变fillColor of UIGraphicsGetCurrentContext？
如何改变fillColor of UIGraphicsGetCurrentContext？
提问于 2017-07-14 11:25:04
我编写了这个自定义UIView类来绘制自定义形状
class ShapeView: UIView {
var color: UIColor?
init(frame: CGRect, color: UIColor) {
super.init(frame: frame)
self.color = color
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func draw(_ rect: CGRect) {
super.draw(rect)
drawShape(rect: rect, color: self.color!)
}
func drawShape(rect: CGRect,color: UIColor) {
guard let ctx = UIGraphicsGetCurrentContext() else { return }
ctx.setFillColor(UIColor.clear.cgColor)
ctx.beginPath()
ctx.move(to: CGPoint(x: rect.width / 2, y: 0))
ctx.addLine(to: CGPoint(x: rect.width, y: rect.height / 2))
ctx.addLine(to: CGPoint(x: rect.width / 2 , y: rect.height))
ctx.addLine(to: CGPoint(x: 0, y: rect.height / 2))
ctx.closePath()
ctx.setFillColor(color.cgColor)
ctx.fillPath()
ctx.strokePath()
}
override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
let path = UIBezierPath(ovalIn: self.frame)
return path.contains(point)
}当用户按下该形状内的某个位置时，我需要更改该形状的fillColor，让我们用此代码//来表示黑色，而调试颜色并没有改变，这看起来像是我做错了什么。
在一些UIViewController类中，我编写了这个方法
class SomeClass: UIViewController {
var shape1: ShapeView?
var frame: CGRect?
override func viewDidLoad() {
let x = view.frame.midX
let y = view.frame.midY
self.frame = CGRect(x: x, y: y, width: 100, height: 100)
super.viewDidLoad()
self.shape1 = ShapeView(frame: frame!, color: .red)
shape1?.backgroundColor = .clear
view.addSubview(shape1!)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let location = touches.first!.location(in: self.view)
if (shape1?.point(inside: location, with: event))! {
print("inside shape1")
shape1?.drawShape(rect: frame!, color: .black)
} else {
print("outside shape1")
shape1?.drawShape(rect: frame!, color: .red)
}
}任何想法！
回答 2
Stack Overflow用户
回答已采纳
发布于 2017-07-14 12:37:59
不要直接调用您的drawShape() func --每次对象绘制自己时都会调用它：
override func draw(_ rect: CGRect) {
super.draw(rect)
drawShape(rect: rect, color: self.color!)
}因此，它将立即将填充颜色更改为shape1的color属性。
相反，可以这样做(没有测试，只需在这里输入)：
if (shape1?.point(inside: location, with: event))! {
print("inside shape1")
shape1?.color = UIColor.black
} else {
print("outside shape1")
shape1?.color = UIColor.red
}
shape1?.setNeedsDisplay()编辑：您还可以像这样修改ShapeView类：
var color: UIColor? {
didSet {
self.setNeedsDisplay()
}
}这将消除在touches处理程序中“手动”调用.setNeedsDisplay()的需要。
编辑2：您可以将它粘贴到游乐场页面中，并且它应该不受更改地运行.
import UIKit
import PlaygroundSupport
class ShapeView: UIView {
var color: UIColor? {
didSet {
self.setNeedsDisplay()
}
}
init(frame: CGRect, color: UIColor) {
super.init(frame: frame)
self.color = color
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func draw(_ rect: CGRect) {
super.draw(rect)
drawShape(rect: rect, color: self.color!)
}
func drawShape(rect: CGRect,color: UIColor) {
guard let ctx = UIGraphicsGetCurrentContext() else { return }
ctx.setFillColor(UIColor.clear.cgColor)
ctx.beginPath()
ctx.move(to: CGPoint(x: rect.width / 2, y: 0))
ctx.addLine(to: CGPoint(x: rect.width, y: rect.height / 2))
ctx.addLine(to: CGPoint(x: rect.width / 2 , y: rect.height))
ctx.addLine(to: CGPoint(x: 0, y: rect.height / 2))
ctx.closePath()
ctx.setFillColor(color.cgColor)
ctx.fillPath()
ctx.strokePath()
}
override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
let path = UIBezierPath(ovalIn: self.frame)
return path.contains(point)
}
}
class VCA : UIViewController {
var shape1: ShapeView?
var frame: CGRect?
override func viewDidLoad() {
let x = view.frame.midX
let y = view.frame.midY
self.frame = CGRect(x: x, y: y, width: 100, height: 100)
super.viewDidLoad()
self.shape1 = ShapeView(frame: frame!, color: .red)
shape1?.backgroundColor = .clear
view.addSubview(shape1!)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let location = touches.first!.location(in: self.view)
if (shape1?.point(inside: location, with: event))! {
print("inside shape1")
shape1?.color = UIColor.black
} else {
print("outside shape1")
shape1?.color = UIColor.red
}
}
}
let vcA = VCA()
vcA.view.backgroundColor = .yellow
PlaygroundPage.current.liveView = vcA.view在操场页面上运行的结果的屏幕记录：
Stack Overflow用户
发布于 2017-07-14 12:44:59
就像这样，
import UIKit
class ShapeView: UIView {
override init(frame: CGRect) {
super.init(frame: frame)
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func draw(_ rect: CGRect) {
super.draw(rect)
drawShape(rect: rect)
}
func drawShape(rect: CGRect) {
guard let ctx = UIGraphicsGetCurrentContext() else
{ return }
ctx.setFillColor(UIColor.red.cgColor)
ctx.beginPath()
ctx.move(to: CGPoint(x: rect.width / 2, y: 0))
ctx.addLine(to: CGPoint(x: rect.width, y: rect.height / 2))
ctx.addLine(to: CGPoint(x: rect.width / 2 , y: rect.height))
ctx.addLine(to: CGPoint(x: 0, y: rect.height / 2))
ctx.closePath()
ctx.fillPath()
ctx.strokePath()
}
override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
let path = UIBezierPath(ovalIn: self.frame)
return path.contains(point)
}} 和
class SomeClass: UIViewController {
var shape1: ShapeView?
var frame: CGRect?
override func viewDidLoad() {
super.viewDidLoad()
let x = view.frame.midX
let y = view.frame.midY
shape1 = ShapeView(frame: CGRect(x: x, y: y, width: 100, height: 100))
view.addSubview(shape1!)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let location = touches.first!.location(in: self.view)
if (shape1?.point(inside: location, with: event))! {
print("inside shape1")
shape1?.backgroundColor = .green
} else {
print("outside shape1")
shape1?.backgroundColor = .black
}
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/45101814
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