Randomizing strings without duplication

I have string with 5 different sayings and I'm trying to make them random without any duplication and repeat the saying once they all have been picked.

so far i have

final String[] mySays = { " x ", " y ", " z" , " a ", " b",}

@Override public void onClick(View v) { //change number to however number there is of "saying" int aNumber = (int) (Math.random() * 5); textOne.setText(mySays[aNumber]);

what can i add to this?

any help is greatly appreciated.