SwiftUI ForEach 理解变量用法

Posted 2023-02-23

【中文标题】SwiftUI ForEach 理解变量用法

【英文标题】：SwiftUI ForEach understanding variable usage

【发布时间】：2019-11-27 09:53:30

【问题描述】：

以下代码对我有用...

VStack 
    ForEach(0..<self.rows, id: \.self)  row in
        HStack 
            ForEach(0..<self.columns, id: \.self)  column in

                //let data = self.item(row: row, column: column)

                Group 
                    if self.item(row: row, column: column) != nil 

                        self.content(self.item(row: row, column: column)!).frame(width: geometry.size.width/CGFloat(self.columns))

                     else 
                        Spacer()
                    
                
            
        
    

但是，当我取消注释 data 变量并将 item() 调用替换为数据使用情况时，甚至添加 return Group 它停止工作并且无法推断返回类型？

【问题讨论】：

您不能在函数构建器中声明变量，比较***.com/q/56616368/1187415 是否有类似问题。

【参考方案1】：

在 Xcode 12 beta 中，只需将类型添加到参数。

我的示例代码： （我更喜欢划分 SwiftUi 的东西.. 否则太乱了..） 查看附近的颜色

struct Issue: Identifiable
        var id  = UUID()
        var name = ""
        var fakeMsg = ""
        var operatorInCharge = ""
        var solved = false
    
    
    

struct CurrentIssuesView: View 
    
    let roomIssues = [
        Issue(name: "ROOM 1", fakeMsg: "2020-09-05 proiettore", operatorInCharge: "m.a", solved: true),
        Issue(name: "ROOM 1", fakeMsg: "2020-09-04 wifi", operatorInCharge: "a.b"),
        Issue(name: "ROOM 2", fakeMsg: "2020-09-04 Audio", operatorInCharge: "m.c", solved: true),
        Issue(name: "ROOM 3", fakeMsg: "2020-09-04 KBD", operatorInCharge: "m.d")
    ]
    
    
    var body: some View 
        
        let vs = VStack
            
            Text("Current ISSUES")
            
            List(roomIssues)  (issue: Issue) in
                
                let color = issue.solved ? Color.green : Color.red
                HStack
                    Text(issue.name).font(.system(size: 20)).foregroundColor(color)
                    Text(issue.fakeMsg)
                
            
        
        return vs
    

我明白了：