flutter - 如何创建自定义异常并在 dart 中处理它

Question

我编写了这段代码来测试自定义异常在 dart 中的工作方式。
我没有得到所需的输出，有人可以向我解释如何处理吗？？

void main() 
{   
  try
  {
    throwException();
  }
  on customException
  {
    print("custom exception is been obtained");
  }
  
}

throwException()
{
  throw new customException('This is my first custom exception');
}

Answer 1

你可以看看Exception part of A Tour of the Dart Language .
以下代码按预期工作(custom exception has been obtained 显示在控制台中):

class CustomException implements Exception {
  String cause;
  CustomException(this.cause);
}

void main() {
  try {
    throwException();
  } on CustomException {
    print("custom exception has been obtained");
  }
}

throwException() {
  throw new CustomException('This is my first custom exception');
}