How to Retrieve a List object from the firebase in android

Question

I am having trouble retrieving a List from the Firebase. I have no trouble storing it, but as soon as I try to cast dataSnapshot.getValue() to ArrayList my app crashes, givi

Answer 1

Apparently, the GenericTypeIndicator doesn't work for all List objects particularly when the object contains none primitive types like maps. So, if it didn't work for your use case as it didn't for me, try this alternate solution:

 @Override
 public void onDataChange(DataSnapshot dataSnapshot) {

    List tDlist = new ArrayList<>();

    for (DataSnapshot d: dataSnapshot.getChildren()){
        TaskDes tD = d.getValue(TaskDes.class);
        tDlist.add(tD);
    }

    notifyDataSetChanged();
 }

As mentioned in the previous answers make sure your class( like TaskDes in this case) has a public constructor which is empty so the getValue method can deserialize correctly to your java class.