Flutter 类型判断：使用 switch case 和 runtimeType

在 Flutter 中，可以使用'runtimeType'属性获取对象的类型，然后使用'switch case'语句来判断类型。示例代码如下：

void main() {
  var obj1 = 'hello';
  var obj2 = 123;
  var obj3 = true;

  switch (obj1.runtimeType) {
    case String:
      print('obj1 is a String');
      break;
    case int:
      print('obj1 is an int');
      break;
    case bool:
      print('obj1 is a bool');
      break;
    default:
      print('obj1 is of unknown type');
  }

  switch (obj2.runtimeType) {
    case String:
      print('obj2 is a String');
      break;
    case int:
      print('obj2 is an int');
      break;
    case bool:
      print('obj2 is a bool');
      break;
    default:
      print('obj2 is of unknown type');
  }

  switch (obj3.runtimeType) {
    case String:
      print('obj3 is a String');
      break;
    case int:
      print('obj3 is an int');
      break;
    case bool:
      print('obj3 is a bool');
      break;
    default:
      print('obj3 is of unknown type');
  }
}

输出结果：

obj1 is a String
obj2 is an int
obj3 is a bool