public class frontPage extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {

public static ArrayList<String> posts = new ArrayList<>();
ArrayAdapter<String> adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_front_page);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    loadSavedPreferences();
    ListView entryList = (ListView) findViewById(R.id.entryList);

    if (posts != null && posts.size() > 0) {
            adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, posts.toArray(new String[1]));
            entryList.setAdapter(adapter);
    }

    entryList.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
        @Override
        public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
            posts.remove(position);
            adapter.notifyDataSetChanged();

            Toast.makeText(frontPage.this, "Item Deleted", Toast.LENGTH_LONG).show();
            return true;
        }
    });


private void savePreferences() {
    SharedPreferences sharedPreferences = getPreferences(Context.MODE_PRIVATE);
    String entryString = "";

    for(int i = 0; i < posts.size(); i++) {
        entryString += posts.get(i) + "|";
    }
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString("posts", entryString);
    editor.commit();

}

private void loadSavedPreferences() {
    SharedPreferences sharedPreferences = getPreferences(Context.MODE_PRIVATE);
    String entryString = sharedPreferences.getString("posts", "");
    StringTokenizer tokenizer = new StringTokenizer(entryString, "|");
    while(tokenizer.hasMoreTokens()) {
        posts.add(tokenizer.nextToken());
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString("posts", entryString);
        editor.commit();
    }
}

@Override
protected void onDestroy() {
    super.onDestroy();
    savePreferences();
    finish();
}