SwiftUIの複雑なレイアウト

余白をつけて、３分割する

 
GeometryReader { geometry in
            
            VStack {
                
                GeometryReader { geometry1 in
                    HStack(spacing: 0) {
                        
                        Text("1").frame(width: geometry1.size.width / 3)
                            .background(Color.green)
                        
                        Text("2").frame(width: geometry1.size.width / 3)
                            .background(Color.orange)
                        
                        Text("3").frame(width: geometry1.size.width / 3)
                            .background(Color.yellow)
                        
                    }
                    .background(Color.blue)
                }
                
            }
            .frame(width: geometry.size.width * 0.9)
            .frame(width: geometry.size.width)
            
        }
    }

さらに分割

struct Main_Footer: View {
    
    var body: some View {
        
        GeometryReader { geometry in
            
            VStack {
                
                GeometryReader { geometry in
                    HStack(spacing: 0) {
                        
                        Text("1").frame(width: geometry.size.width * 0.3)
                            .background(Color.green)
                        
                        Text("2").frame(width: geometry.size.width * 0.4)
                            .background(Color.orange)
                        
                        HStack(spacing: 0) {
                            Text("3")
                                .frame(maxWidth: .infinity)
                                .background(Color.blue)
                            Text("4")
                                .frame(maxWidth: .infinity)
                                .background(Color.black)

                        }
                        .frame(width: geometry.size.width * 0.3)
                        .background(Color.yellow)
                        
                        
                    }
                    .background(Color.blue)
                }
                
            }
            .frame(width: geometry.size.width * 0.9)
            .frame(width: geometry.size.width)
            
        }
    }
}

 GeometryReader { geometry in
            VStack {
                GeometryReader { geometry in
                    HStack(spacing: geometry.size.width * 0.03) {
                        
                        Text("1")
                            .frame(maxWidth: .infinity, maxHeight: .infinity)
                            .background(Color.white)
                        
                        Text("2")
                            .frame(maxWidth: .infinity, maxHeight: .infinity)
                            .background(Color.white )
                    }

                }
            }
            .frame(width: geometry.size.width * 0.9, height: geometry.size.height)
            .frame(width: geometry.size.width)
        }

Bindingでデフォルト設定

struct Row: View {
    
    let title: String
    
    @Binding var value: String
    
    
    init(title: String , value: Binding<String> = .constant("未")) {
        self.title = title
        _value = value
    }
    
    var body: some View {
        
        HStack {
            Text(title)
                .font(.caption)
                
            Text(value)
        }
    }
}

Codableでクラス継承対応

import UIKit

var data = """
{
    "A": "A",
    "B": "B",
    "C": "C",
}
"""

class A : Codable {
    
    var A:String = "A"
    
    enum CodingKeys: String, CodingKey {
        case A = "A"
    }
    
    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(A, forKey: .A)
    }
}

class B: A {
    
    var B:String = "B"

    enum CodingKeys: String, CodingKey {
        case B = "B"
        case A = "A"
    }
    
    override func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(B, forKey: .B)
        try container.encode(A, forKey: .A)
    }
}

var b = B()
b.A = "やべい"
b.B = "すごい"

var enc = try! JSONEncoder().encode(b)
print(String(data: enc, encoding: .utf8)!)


var a = A()
a.A = "どすこい"

var enc1 = try! JSONEncoder().encode(a)
print(String(data: enc1, encoding: .utf8)!)