MainView.java

public class MainView {
    private final Bus bus;
    private WeakReference<AppCompatActivity> activityRef;
  
    public MainView(AppCompatActivityactivity, Bus bus) {
        activityRef = new WeakReference<>(activity);
        this.bus = bus;
    }

    @Nullable
    public AppCompatActivity getActivity() {
        return activityRef.get();
    }
}