Since you'll be traveling through time, you might end up in an era that (Gasp!) doesn't have wifi. Create an intent filt

import android.os.Bundle;
import android.view.View;

public class TimeTravelActivity extends Activity {

  public String targetYear;

  private NetworkConnectionReceiver receiver = new NetworkConnectionReceiver();

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

    Intent intent = getIntent();
    targetYear = intent.getStringExtra("EXTRA_YEAR");
    EnergySource source = (EnergySource)intent.getParcelableExtra("EXTRA_ENERGY");
    //NetworkConnectionReceiver mReceiver = new NetworkConnectionReceiver();
    IntentFilter filter = new IntentFilter("android.net.conn.CONNECTIVITY_CHANGE");
    registerReceiver(receiver,filter);
  }
  @Override
protected void onResume(){
super.onResume();
IntentFilter filter = new IntentFilter("android.net.comm.CONNECTIVITY_CHANGE");
registerReceiver(receiver,filter);
}
@Override
protected void onPause(){
super.onPause();
//IntentFilter filter = new IntentFilter("android.net.comm.CONNECTIVITY_CHANGE");
//unregisterReceiver(receiver);
}
}