Flutter 模型动态化赋值研究分析

/// 编码
Map<String, Object?>toJson()
/// 解码
... fromJson(Map<String, Object?>? map) 

var model = AppModel(
    appIcon: "assets/icon_light_unselected.png",
    appSize: "53.2M",
    appName: "QQ音乐 - 让生活充满音乐",
    appDate: "13:50",
    appDescription: """【全新设计 纯净享受】
-重塑全新视觉，轻盈/纯净/无扰/为Mac系统量身设计，从内而外纯净享受；
-全新结构设计，整体交互优化/人性化和易用性大提升，操作体验豪华升级"；
""",
    appVersion: "版本 7.6.0",
    isShowAll: false
);
print("appName before: ${model["appName"]}");//appName before: QQ音乐 - 让生活充满音乐
model["appName"] = "哈哈哈哈";
print("appName after: ${model["appName"]}");//appName after: 哈哈哈哈

///升级模型
class AppModel {
    AppModel({
      this.appIcon = "-",
      this.appSize = "-",
      this.appName = "-",
      this.appDate = "-",
      this.appDescription = "-",
      this.appVersion = "-",
      this.isShowAll = false,
    });
    /// App图标
    String appIcon;
    /// App名称
    String appName;
    /// App大小
    String appSize;
    /// App更新日期
    String appDate;
    /// App更新文案
    String appDescription;
    /// App版本
    String appVersion;
    /// App更新文案
    bool isShowAll;
    static AppModel? fromJson(Map<String, Object?>? map) {
    if (map == null) {
      return null;
    }
    return AppModel(
      appIcon: map["appIcon"].toString(),
      appSize: map["appSize"].toString(),
      appName: map["appName"].toString(),
      appDate: map["appDate"].toString(),
      appDescription: map["appDescription"].toString(),
      appVersion: map["appVersion"].toString(),
      isShowAll: map["isShowAll"] as bool,
      );
    }
    Map<String, Object?>toJson() {
      return {
        "appIcon": this.appIcon,
        "appSize": this.appSize,
        "appName": this.appName,
        "appDate": this.appDate,
        "appDescription": this.appDescription,
        "appVersion": this.appVersion,
        "isShowAll": this.isShowAll,
      };
    }
    Object? operator [](String key){
      final map = this.toJson();
      final result = map[key];
      return result;
    }
    void operator []=(String key, dynamic value){
      switch (key) {
        case "appName":
          this.appName = value;
          break;
        case "appIcon":
          this.appIcon = value;
          break;
        case "appSize":
          this.appSize = value;
          break;
        case "appName":
          this.appName = value;
          break;
        case "appDate":
          this.appDate = value;
          break;
        case "appDescription":
          this.appDescription = value;
          break;
        case "appVersion":
          this.appVersion = value;
          break;
        case "isShowAll":
          this.isShowAll = value;
          break;
        default:
          break;
      }
    }
}