MainActivity.java

package net.rehacktive.waspdbexample;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ListView;
import android.widget.ProgressBar;

import net.rehacktive.waspdb.WaspDb;
import net.rehacktive.waspdb.WaspFactory;
import net.rehacktive.waspdb.WaspHash;
import net.rehacktive.waspdb.WaspListener;
import net.rehacktive.waspdb.WaspObserver;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends ActionBarActivity {

    ProgressBar progressBar;
    // wasp objects
    WaspDb db;
    WaspHash hash;
    WaspObserver observer;

    UserAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        progressBar = (ProgressBar) findViewById(R.id.progressBar);

        ListView userList = (ListView) findViewById(R.id.userlist);
        adapter = new UserAdapter(this);
        userList.setAdapter(adapter);

        if(db==null) {
            progressBar.setVisibility(View.VISIBLE);
            WaspFactory.openOrCreateDatabase(getFilesDir().getPath(), "example", "Passw0rd", new WaspListener<WaspDb>() {
                @Override
                public void onDone(WaspDb waspDb) {
                    db = waspDb;
                    hash = db.openOrCreateHash("users");

                    progressBar.setVisibility(View.INVISIBLE);

                    getUsers();

                    observer = new WaspObserver() {
                        @Override
                        public void onChange() {
                            List<User> users = hash.getAllValues();
                            adapter.setUsers(users);
                            adapter.notifyDataSetChanged();
                        }
                    };

                    hash.register(observer);
                }
            });
        }
    }

    private void getUsers() {
        List<User> users = hash.getAllValues();
        if(users==null)
            users = new ArrayList<>();

        adapter.setUsers(users);
        adapter.notifyDataSetChanged();
    }

    private void addUser() {
        User user = new User("user "+System.currentTimeMillis(), "");
        hash.put(user.getUser_name(),user);
    }

    private void flushUsers() {
        hash.flush();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        hash.unregister(observer);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.add_user) {
            addUser();
            return true;
        }

        if (id == R.id.flush_user) {
            flushUsers();
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}