Java – Make the dialog box appear once

I have an alert dialog in my app that starts as soon as the application starts. I want my alertDialog to only show up on first launch after the activity is installed I don’t want alertDialog to pop up again unless the user removes the app and then installs it again. I tried to see how to implement this approach and tried to learn to write the right code, but I couldn’t seem to do it properly. Then someone can help me implement this method and solve this problem.

    public class MainActivity extends Activity {

@Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
    boolean initialDialogDisplayed = preferences.getBoolean("InitialDialog", false);
    if (!initialDialogDisplayed) {
        Editor editor = preferences.edit();
        editor.putBoolean("InitialDialog", true);
        editor.commit();

final AlertDialog.Builder alertDialog = new AlertDialog.Builder(this);

alertDialog.setTitle("Alert");
        alertDialog.setIcon(R.drawable.ic_launcher);
        alertDialog.setMessage("Dialog");

alertDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {

}
         });

alertDialog.show();
                final EditText et = (EditText) findViewById(R.id.editText1);
                Button getAnswer = (Button) findViewById(R.id.button1);
                getAnswer.setOnClickListener(new OnClickListener() {
                    @Override
                    public void onClick(View v) {       
                        if (et.getText().toString().length()==0) {
                            Toast.makeText(getApplicationContext(),"Can't Be Blank!",Toast.LENGTH_LONG).show();             

}else{
                            EditText et = (EditText) findViewById(R.id.editText1);
                            String searchTerm = et.getText().toString().trim();         
                            Intent in = new Intent(MainActivity.this, ListView.class);
                            in.putExtra("TAG_SEARCH", searchTerm);
                            startActivity(in);
                        }

}
                });
            }
         }

@Override
        protected void onStop() {
             TODO Auto-generated method stub
            super.onStop();
        }}

You can store flag values through SharedPreferences.

 SharedPreferences settings = getSharedPreferences("pref_name", 0);
 boolean installed = settings.getBoolean("installed", false);

if(!installed){

showDialog

SharedPreferences.Editor editor = settings.edit();
   editor.putBoolean("installed", true);
   editor.commit();

}

Link: http://developer.android.com/guide/topics/data/data-storage.html#pref