I haven't tested this code but it should work:
AlertDialog dialog = ...
dialog.getButton(DialogInterface.BUTTON_POSITIVE).performClick();
Alternatively, if you don't want to keep a reference to the dialog but are in control of its setup, you could extract the on click code into another method:
AlertDialog.Builder builder = ...
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
onPositiveButtonClicked();
}
});
and implement onPositiveButtonClicked() in your Activity. Instead of programatically clicking the OK button you can call onPositiveButtonClicked() and dismissDialog(id). If you need to handle multiple dialogs, have onPositiveButtonClicked take an id parameter.