Handlerpublic class MyHandler extends Handler private final

public class MyHandler extends Handler {
    private final WeakReference<MainActivity> mWeakReference;

    public MyHandler(@NonNull Looper looper, MainActivity activity) {
        super(looper);
        this.mWeakReference = new WeakReference<>(activity);
    }

    @Override
    public void handleMessage(@NonNull Message msg) {
        MainActivity mainActivity = mWeakReference.get();
        switch (msg.what) {
            
        }
    }
}