To implement sheet level access step by step or more deep level App objects level access please refer this document:
I checked but not working.
I have a user who has access to an application and he can see all the sheets.How to restrict all the sheets.
Only one sheet can be visible and under that sheet one object can be visible to user.
I suggest you to use Audit on QMC to know which security rule is granting access to all sheets for that user.
Keep in mind that you can't hide a single chart object but you can show it with no data.
As I said before you can't restrict user access to object level but you can create a security rule to deny your user to access your chart dimensions and measures.
Doing this you'll get the message "no data" within the chart object.
Hope this helps.
you should use something as below in your security rule:
( (resource.objectType="measure" and resource.name like "*") or (resource.objectType="dimension" and resource.name like "*") )
Hope it helps.