Json int to double解析Flutter

Question

问题是我想从这个：{“cost”：0}解析到双倍。所以我现在所拥有的：

null

factory ShippingMethod.fromJson(Map<String, dynamic> json) {
    dynamic cost = json['cost'];
    print(cost.runtimeType);  // printing runtime type and I get it twice!
    return ShippingMethod(
      code: json['code'],
      title: json['title'],
      description: json['description'],
      cost: cost.toDouble(),
      taxClassId: json['tax_class_id'],
    );
  }

I/flutter (  480): int    // first it gives me int 
I/flutter (  480): String  // second it gives me String
E/flutter (  480): [ERROR:flutter/lib/ui/ui_dart_state.cc(166)] Unhandled Exception: NoSuchMethodError: Class 'String' has no instance method 'toDouble'.
E/flutter (  480): Receiver: "0"
E/flutter (  480): Tried calling: toDouble()

此外，以下是我从服务器获得的信息：

...
"pickup": {
                        "code": "pickup.pickup",
                        "title": "Standard",
                        "description": "If the cost of the order ...",
                        "cost": 0,
                        "tax_class_id": 0,
                        "text": "0.00 TMT"
                    }
...

飞镖让我开心！..是虫子还是怎么的？

Answer 1

1. 要将字符串转换为double，我们有一个函数:double.parse（string）
2. JSON[“cost”]返回一个int值，因此我们应该将其转换为字符串，然后将其传递给“double.parse（string）”。

解决方案代码：

double.parse(json["cost"].toString());