Is there a way to make an alert only appear when the app is opened? I'm creating an alert in onStart() in my MainActivity and whenever I go back to that activity in the app, it shows the alert again which can be annoying to the user. Or is there a way to create a "got it" button and then turn off the alert? Here is my code:

```
protected void onStart() {
    super.onStart();
    new AlertDialog.Builder(this)
            .setTitle("Instructions")
            .setMessage("Hello! To begin, select a map from the list to train with. Make sure" +
                    " you are on the correct floor.")
            .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                }
            })
            .setIcon(R.drawable.ic_launcher)
            .show();

}

```