自定义颜色导致Live Activities无法显示问题求助

你使用的Color Codable扩展没有适配从Assets目录加载的自定义颜色。原扩展仅支持系统预定义颜色（如.red）和基于RGB/HSL数值初始化的颜色，但对于Color("YourCustomColor")这类依赖资源名称的颜色，编码解码过程中会丢失关键的资源标识信息，导致解码后的Color对象无效，最终触发Live Activity渲染失败，所以锁屏上完全看不到活动内容。

修改Color的Codable扩展，增加对资源名称类型Color的支持。核心思路是在编码时识别资源颜色并存储其名称，解码时根据存储的信息还原对应的颜色：

extension Color: Codable {
    private enum CodingKeys: String, CodingKey {
        case resourceName
        case rgbComponents
        case systemColorName
    }
    
    public init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        
        // 优先尝试解码资源名称对应的颜色
        if let resourceName = try container.decodeIfPresent(String.self, forKey: .resourceName) {
            self.init(resourceName)
        }
        // 其次解码RGB数值颜色
        else if let rgb = try container.decodeIfPresent((Double, Double, Double, Double).self, forKey: .rgbComponents) {
            self.init(red: rgb.0, green: rgb.1, blue: rgb.2, opacity: rgb.3)
        }
        // 最后处理系统预定义颜色
        else if let systemName = try container.decodeIfPresent(String.self, forKey: .systemColorName) {
            switch systemName {
            case "red": self = .red
            case "blue": self = .blue
            case "green": self = .green
            case "yellow": self = .yellow
            case "orange": self = .orange
            // 根据你的需求添加更多系统颜色
            default: self = .clear
            }
        }
        else {
            throw DecodingError.dataCorrupted(.init(codingPath: decoder.codingPath, debugDescription: "无法解析该类型的Color"))
        }
    }
    
    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        
        // 尝试识别资源颜色（通过解析description，注意：该方式依赖Apple的格式实现，若后续格式变更需调整）
        let colorDescription = self.description
        if colorDescription.contains("NamedColor") {
            let nameComponents = colorDescription.components(separatedBy: "\"")
            guard nameComponents.count >= 2 else {
                // 无法提取名称时 fallback 到RGB编码
                try encodeAsRGB(to: &container)
                return
            }
            try container.encode(nameComponents[1], forKey: .resourceName)
            return
        }
        
        // 识别系统颜色
        switch self {
        case .red: try container.encode("red", forKey: .systemColorName)
        case .blue: try container.encode("blue", forKey: .systemColorName)
        case .green: try container.encode("green", forKey: .systemColorName)
        case .yellow: try container.encode("yellow", forKey: .systemColorName)
        case .orange: try container.encode("orange", forKey: .systemColorName)
        // 按需添加更多系统颜色
        default:
            // 其他情况按RGB编码
            try encodeAsRGB(to: &container)
        }
    }
    
    // 辅助方法：将Color转为RGB组件编码
    private func encodeAsRGB(to container: inout KeyedEncodingContainer<CodingKeys>) throws {
        #if os(iOS) || os(tvOS) || os(watchOS)
        let uiColor = UIColor(self)
        var red: CGFloat = 0, green: CGFloat = 0, blue: CGFloat = 0, alpha: CGFloat = 0
        uiColor.getRed(&red, green: &green, blue: &blue, alpha: &alpha)
        try container.encode((Double(red), Double(green), Double(blue), Double(alpha)), forKey: .rgbComponents)
        #elseif os(macOS)
        let nsColor = NSColor(self)
        guard let rgbColor = nsColor.usingColorSpace(.sRGB) else {
            throw EncodingError.invalidValue(self, .init(codingPath: container.codingPath, debugDescription: "无法转换为sRGB颜色空间"))
        }
        try container.encode((rgbColor.redComponent, rgbColor.greenComponent, rgbColor.blueComponent, rgbColor.alphaComponent), forKey: .rgbComponents)
        #endif
    }
}

上面通过解析description识别资源颜色的方式存在一定风险（Apple可能修改描述格式）。如果需要更稳定的实现，可以自定义一个CodableColor结构体来封装不同类型的颜色：

enum CodableColor: Codable, Hashable {
    case resource(name: String)
    case rgb(red: Double, green: Double, blue: Double, opacity: Double)
    case system(name: String)
    
    // 转换为SwiftUI Color
    var color: Color {
        switch self {
        case .resource(let name):
            return Color(name)
        case .rgb(let red, let green, let blue, let opacity):
            return Color(red: red, green: green, blue: blue, opacity: opacity)
        case .system(let name):
            switch name {
            case "red": return .red
            case "blue": return .blue
            case "green": return .green
            default: return .clear
            }
        }
    }
}

// 在ContentState中使用CodableColor替代Color
struct ContentState: Codable, Hashable {
    var elapsedTime: Int
    var remainingTime: Int
    var meetingDuration: Double
    var mainColor: CodableColor
}

// 在视图中使用时转换为Color
.background(context.state.mainColor.color)

• 确保自定义颜色资源在WidgetExtension目标的资源目录中也存在，否则Live Activity无法加载该颜色。
• Live Activity的ContentState必须完全可安全编码解码，任何无效的对象都会导致Activity无法渲染。

内容的提问来源于stack exchange，提问作者LucasC