Question

在Flutter中，无论我尝试解码哪个json文件，我都得到相同的标题错误。最初，我认为这与我的项目有关，但是在启动新的模板Flutter项目后，我仍然收到相同的错误。我的根文件夹中有json文件，并将它们添加到pubspec.yaml文件中：

  assets:
      - Sample-JSON-data.json
      - Sample-employee-JSON-data.json

当前的Main.dart代码：

    var jsonString = 'Sample-JSON-data.json';
    var response = jsonDecode(jsonString);
    print(response);

我已经在多个测试站点上验证了我的json数据，并在Flutter Documentation中尝试了各种方法。杰森数据：

{
    "type": "FeatureCollection",
    "features": [
        {
            "type": "Feature",
            "geometry": {
                "type": "Point",
                "coordinates": [
                    151.0763783444317,
                    -33.98045132346684
                ]
            }
        },
        {
            "type": "Feature",
            "geometry": {
                "type": "Point",
                "coordinates": [
                    151.07774912725728,
                    -33.97470462237792
                ]
            }
        },
        {
            "type": "Feature",
            "geometry": {
                "type": "Point",
                "coordinates": [
                    151.07774912725728,
                    -33.97470462237792
                ]
            }
        },
        {
            "type": "Feature",
            "geometry": {
                "type": "Point",
                "coordinates": [
                    151.07774912725728,
                    -33.97470462237792
                ]
            }
        },
        {
            "type": "Feature",
            "geometry": {
                "type": "Point",
                "coordinates": [
                    151.0763783444317,
                    -33.98045132346684
                ]
            }
        },
        {
            "type": "Feature",
            "geometry": {
                "type": "Point",
                "coordinates": [
                    151.07774912725728,
                    -33.97470462237792
                ]
            }
        },
        {
            "type": "Feature",
            "geometry": {
                "type": "Point",
                "coordinates": [
                    151.07774912725728,
                    -33.97470462237792
                ]
            }
        },
        {
            "type": "Feature",
            "geometry": {
                "type": "Point",
                "coordinates": [
                    151.07774912725728,
                    -33.97470462237792
                ]
            }
        },
        {
            "type": "Feature",
            "geometry": {
                "type": "Point",
                "coordinates": [
                    151.0763783444317,
                    -33.98045132346684
                ]
            }
        }
    ]
}

Answer 1

jsonDecode期望输入是有效的JSON，序列化为String fe。 { "message": "Hello World!" }。这样就可以了：jsonDecode('{"message": "Hello World!"}')。

您要传递给它的是文件名，它不会自动为您读取文件。您可以在此处检查操作方法：

Flutter - Read text file from assets

Answer 2

实际上，您不是从json文件中加载数据。

尝试：

var jsonString = await rootBundle.loadString('Sample-JSON-data.json')

颤振：意外字符（在字符1处）

2 个答案: