Question

我正在从JSON提取数据，但出现此错误。

...
switch (vModel->getDrawMode())
{
case 0: //GL_POINTS
    //glPointSize(6.0);
  glDrawArrays(GL_POINTS, 0, vModel->getVertices().size());
  break;

case 1: //GL_LINES
    //glEnable(GL_LINE_SMOOTH);
    //GLint range[2];
    //glGetIntegerv(GL_ALIASED_LINE_WIDTH_RANGE,range);
  glDrawArrays(GL_LINES, 0, vModel->getVertices().size());
  break;

case 2: //GL_LINE_LOOP
  glDrawArrays(GL_LINE_LOOP, 0, vModel->getVertices().size());
  break;

case 3: //GL_LINE_STRIP
  glDrawArrays(GL_LINE_STRIP, 0, vModel->getVertices().size());
  break;
}

上述错误的代码段-

    > I/flutter ( 4999): NoSuchMethodError: The method '[]' was called on null.     
    > I/flutter ( 4999): Receiver: null
    > I/flutter ( 4999): Tried calling: []("thumbnail")

打印输出（parsedJson）-

factory ImageLinks.fromJson(Map<String, dynamic> parsedJson) {
    final finger = parsedJson["thumbnail"];
    print(finger);
    return ImageLinks(
      thumb: finger,
    );
  }

请帮助！

Answer 1

我想您正在使用http软件包。您是否解码了响应数据？

Map<String, dynamic> parsedJson = jsonDecode(jsonString);

NoSuchMethodError：方法'[]'在null |上被调用。解析JSON

1 个答案: