[1.17.1] How to change the property of an entity by command

[Tats]

Thanks to this forum, I succeeded to summon my own entity.

Now I want to control it by command, but can not access to it.

 

MyEntity.java has a property, ‘isFlying’ like this:

public class MyEntity extends Animal {
	public boolean isFlying = false;
	…
}

 

And I want to change the flag by command like these, of course failed (showed no error message):

data merge entity @e[type=mymod:myentity, limit=1, name="myentity"] {isFlying: 1b}
data merge entity @e[type=mymod:myentity, limit=1, name="myentity"] {Attributes: [{Name:"generic.isFlying", Base:1b}]}

 

Any good way to change the flag of the entity object?

Thanks in advance.

[Tats]

Thank you for your reply!

At first, the property changed only in server side,  so I used SynchedEntityData, then it worked!!