My code looks like this:
TextView task_text = (TextView) view.findViewById(R.id.task_text);
task_text.setPaintFlags( task_text.getPaintFlags() | Pain
To remove a flag, this should work:
task_text.setPaintFlags( task_text.getPaintFlags() & (~ Paint.STRIKE_THRU_TEXT_FLAG));
Which means set all the set flags, except of Paint.STRIKE_THRU_TEXT_FLAG.
To check if a flag is set (Edit: for a moment I forgot it is java...):
if ((task_text.getPaintFlags() & Paint.STRIKE_THRU_TEXT_FLAG) > 0)