Block Fridays from DatePicker

Question

I'm working on a project with DatePicker. I'm already using setMinDate and setMaxDate, and now I want to block all Fridays.

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    DatePicker date = findViewById(R.id.datePicker4);
    date.setMinDate(System.currentTimeMillis());
    c.add(Calendar.DAY_OF_MONTH,13);
    date.setMaxDate(c.getTimeInMillis());

    date.init(c.get(Calendar.YEAR), c.get(Calendar.MONTH), c.get(Calendar.DAY_OF_MONTH), new DatePicker.OnDateChangedListener() {
        @Override
        public void onDateChanged(DatePicker datePicker, int year, int month, int dayOfMonth) {
            startActivity(new Intent(MainActivity.this,clock.class));
        }
    });
}