Designing an interface for an android app, I stumbled upon a paradox and I'm a bit confused about what to do and why to do.
User wants to delete his/her post's comments.
The button to initiate the delete of an item can be an icon. After clicking this it is considered good practice for irreversible actions have a confirmation / cancel option as either a screen or a little inline control (depending on the magnitude of the delete). At this point the user needs more reassurance of what exactly will happen. They must have confidence that the button they click will have the desired effect. Text is better in this scenario, but you don't have to rely on it alone. You can add some additional visual affordance on which is the primary or secondary action.
Since your delete is an irreversible action, it should have less visual weight than cancel.