如何在 forEach 循环中传递变量函数 [英] How to pass variables functions in forEach loops

问题描述

我目前正在编写一些代码来创建一个六边形网格，每个六边形都用渐变着色.但是，我对 swiftUI 还是很陌生，不完全理解为什么我的代码不起作用.

I am currently working on some code to create a grid of hexagons, each one individually coloured with a gradient. However I am quite new to swiftUI and don't fully understand why my code doesn't work.

ForEach(0 ..< 11, id: \.self) { Xnum in
    ForEach(0 ..< 11, id: \.self) { Ynum in
        self.MyNewPath(in: CGRect(), Xcoord: Double(Xnum), Ycoord: Double(Ynum), Type: 1)
            .fill(RadialGradient(
                gradient: Gradient(colors: [Color.red, Color.blue]),
                center: .init(
                    x: self.gradientParametersX(Xpos: Double(Xnum)),
                    y: self.gradientParametersY(Ypos: Double(Ynum), Xpos: Double(Xnum))),
                startRadius: CGFloat(2.0),
                endRadius: CGFloat(70.0)))
            .gesture(
                TapGesture().onEnded {_ in
                    self.dataEditor(Xplace: Int(Xnum), Yplace: Int(Ynum))
                }
            )
    }
}

返回类型:

• MyNewPath() - Path(六边形)
• gradientParametersY() - CGFloat
• gradientParametersY() - CGFloat

Return Types:

• MyNewPath() - Path (of a hexagon)
• gradientParametersY() - CGFloat
• gradientParametersY() - CGFloat

编译器无法在合理的时间内对该表达式进行类型检查；尝试将表达式分解为不同的子表达式

错误似乎集中在将 Xnum 和 Ynum 传递给函数 gradientParametersX() 和 gradientParametersY().

The error appears to be centred around the passing of Xnum and Ynum to functions gradientParametersX() and gradientParametersY().

例如当我通过 7.0 和 0.0 时:

When I pass 7.0 and 0.0 for example:

x: self.gradientParametersX(Xpos: Double(7.0)),
y: self.gradientParametersY(Ypos: Double(0.0), Xpos: Double(7.0))),

...没有错误.

推荐答案

尝试在单独的函数中单独创建网格项，如下所示(代码快照不可测试，所以只是简单地演示想法)

Try to separate grid item creation in separate function as below (the code snapshot is not testable, so just scratchy to demo idea)

    ...
    ForEach(0 ..< 11, id: \.self) { Xnum in
        ForEach(0 ..< 11, id: \.self) { Ynum in
            self.createItem(for: Xnum, Ynum: Ynum)
        }
    }
    ...

private func createItem(for Xnum: Int, Ynum: Int) -> some View {
    self.MyNewPath(in: CGRect(), Xcoord: Double(Xnum), Ycoord: Double(Ynum), Type: 1)
        .fill(RadialGradient(
            gradient: Gradient(colors: [Color.red, Color.blue]),
            center: .init(
                x: self.gradientParametersX(Xpos: Double(Xnum)),
                y: self.gradientParametersY(Ypos: Double(Ynum), Xpos: Double(Xnum))),
            startRadius: CGFloat(2.0),
            endRadius: CGFloat(70.0)))
        .gesture(
            TapGesture().onEnded {_ in
                self.dataEditor(Xplace: Int(Xnum), Yplace: Int(Ynum))
            }
        )
}

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