I know that it is possible to create an instance from a symbol like is shown in this link:
Create an instance of an object from a String in Dart?
But this doesn't work for me since what I want to do is create an instance without having the class.
This problem is caused because I have One class with an internal List:
class MyNestedClass {
String name;
}
class MyClass {
int i, j;
String greeting;
List<MyNestedClass> myNestedClassList;
}
And I want to convert a map to this class:
{
"greeting": "hello, there",
"i": 3,
"j": 5,
"myNestedClassList": [
{
"name": "someName1"
},{
"name": "someName2"
}
]
}
right now I am doing something like this:
static void jsonToObject(String jsonString, Object object) {
Map jsonMap = JSON.decode(jsonString); //Convert the String to a map
mapToObject(jsonMap, object); //Convert the map to a Object
}
static void mapToObject(Map jsonMap, Object object) {
InstanceMirror im = reflect(object); //get the InstanceMirror of the object
ClassMirror cm = im.type; //get the classMirror of the object
jsonMap.forEach((fieldNameStr, fieldValue) { // For each element in the jsonMap
var fieldName = new Symbol(fieldNameStr); // convert the fieldName in the Map to String
if (isPrimitive(fieldValue)) { // if fieldValue is primitive (num, string, or bool
im.setField(fieldName, fieldValue); //set the value of the field using InstanceMirror
} else if (fieldValue is List) { // else if the fieldValue is a list
ClassMirror listCm = (cm.declarations[fieldName] as VariableMirror).type; //get the class mirror of the list
var listReflectee = listCm.newInstance(const Symbol(''), []).reflectee; //create an instance of the field
for(var element in fieldValue) { //for each element in the list
if(!isPrimitive(element)) { // if the element in the list is a map (i.e not num, string or bool)
var listType = listCm.typeArguments[0]; //get the TypeMirror of the list (i.e MyNestedClass from List<MyNestedClass>)
//This is the line that doesn't work correctly
//It should be something like:
//
// ClassMirror.fromSymbol(listType.simpleName).newInstance(const Symbol(''), []);
//
var listObject = (listType as ClassMirror).newInstance(const Symbol(''), []); //create an instance of the specified listType
mapToObject(element, listObject); //convert the element to Object
}
listReflectee.add(element); //add the element to the list
};
} else { //else (the field value is a map
ClassMirror fieldCm = (cm.declarations[fieldName] as VariableMirror).type; // get the field ClassMirror from the parent declarations
var reflectee = fieldCm.newInstance(const Symbol(''), []).reflectee; //create an instance of the field
mapToObject(fieldValue, reflectee); // convert the fieldValue, which is a map, to an object
im.setField(fieldName, reflectee); // set the value of the object previously converted to the corresponding field
}
});
}
As you can see the lines that are not actually working are:
var listType = listCm.typeArguments[0]; //get the TypeMirror of the list (i.e MyNestedClass from List<MyNestedClass>)
var listObject = (listType as ClassMirror).newInstance(const Symbol(''), []); //create an instance of the specified listType
since they are creating an instance on localClassMirror
and not on MyNestedClass
. I'm looking for a method similar to:
ClassMirror.fromSymbol(listType.simpleName).newInstance(const Symbol(''), []);
you can see the full source code in the next URL:
DSON Source Code