Android :: Dialog Activity To Return Before Continuing Executing Of Main Thread

How would I force the current thread to wait until another has finished before continuing. In my program the user selects a MODE from an AlertDialog, I want to halt executing of the program before continuing as the mode holds important configuration for the gameplay.

new AlertDialog.Builder(this)
.setItems(R.array.game_modes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
switch (which) {
case 0:
setMode(TRAINING_MODE);
case 1:
setMode(QUIZ_MODE);
default:
setMode(TRAINING_MODE);
break; ............
//continue loading the rest of onCreate();
contineOnCreate(); } })
.create().show();

If this is impossible can anyone give a possible solution?