null日期时间差显示在textview中

Question

在我的应用程序中，我正在计算日期时差。在firebase中插入节点时，我节省了创建节点的当前时间。在适配器中，我希望以秒为单位或几天显示cardview的差异。 问题是适配器中没有编译时错误。但是textview中没有显示任何内容。

这是我在firebase中插入节点的活动

        addMovie.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            String currentDateTime = DateFormat.getDateTimeInstance().format(new Date());

            String title = etTitle.getText().toString();
            String desc = etDesc.getText().toString();
            String url = etUrl.getText().toString();
            String cst = etCast.getText().toString();
            savedData(title, desc, url,cst,currentDateTime);
}

    private void savedData(String title, String desc, String url,String cast,String time) {
    String key = updateId;
    if (updateId == null) {
        key = databaseReference.push().getKey();
    }

    uploadImage(selectedimg, key);
    Movie movie = new Movie(title, desc, url, key,cast,time);
    Toast.makeText(this, "movie "+movie.getCast(), Toast.LENGTH_SHORT).show();
    movieReference.child(key).setValue(movie);
    etTitle.setText("");
    etDesc.setText("");
    etUrl.setText("");
    movieImage.setImageResource(0);
    pd.dismiss();
}

这是我的适配器

public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {

ArrayList<Movie> movies;
movieItemListener listener;
Context context;
FirebaseDatabase firebaseDatabase;
DatabaseReference databaseReference;
DecimalFormat df;


public MyAdapter(ArrayList<Movie> movies) {
    this.movies = movies;
}

public MyAdapter(@NonNull Context context, ArrayList<Movie> movies, movieItemListener listener) {
    this.context = context;
    this.movies = movies;
    this.listener = listener;
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.movie_layout, parent, false);
    MyViewHolder viewHolder = new MyViewHolder(view);
    return viewHolder;
}

@Override
public void onBindViewHolder(final MyViewHolder holder, final int position) {


    df = new DecimalFormat("#.#");
    final Movie movie = movies.get(position);

    String currentTime = DateFormat.getDateTimeInstance().format(new Date());
    final String saveTime = movie.getCurrentDateTime();

    Toast.makeText(context, "abc"+getTimeDiff(currentTime, saveTime), Toast.LENGTH_SHORT).show();

    holder.tvDate.setText(getTimeDiff(currentTime, saveTime));

    holder.tvRatings.setText(df.format(movie.getAvgRating()));

    firebaseDatabase = FirebaseDatabase.getInstance();
    databaseReference = firebaseDatabase.getReference().child("movies");

    databaseReference.child(movie.getId()).addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            holder.tvRatings.setText(df.format(dataSnapshot.child("avgRating").getValue()));
            holder.tvViews.setText(String.valueOf(dataSnapshot.child("viewsCount").getValue()) + " Views");
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

    holder.tvTitle.setText(movie.getTitle());

    holder.overflow.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            showPopupMenu(holder.overflow, position, movie);
        }
    });
}

private String getTimeDiff(String currentTime, String saveTime) {
    String diff="";
    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd/M/yyyy hh:mm:ss");

    try {
        Date date1 = simpleDateFormat.parse(currentTime);
        Date date2 = simpleDateFormat.parse(saveTime);

        diff= printDifference(date1, date2);
        Toast.makeText(context, "in diff ", Toast.LENGTH_SHORT).show();

    } catch (ParseException e) {
        e.printStackTrace();
    }
  return diff;
}


public String printDifference(Date startDate, Date endDate) {

    long different = endDate.getTime() - startDate.getTime();

    long secondsInMilli = 1000;
    long minutesInMilli = secondsInMilli * 60;
    long hoursInMilli = minutesInMilli * 60;
    long daysInMilli = hoursInMilli * 24;

    long elapsedDays = different / daysInMilli;
    different = different % daysInMilli;

    long elapsedHours = different / hoursInMilli;
    different = different % hoursInMilli;

    long elapsedMinutes = different / minutesInMilli;
    different = different % minutesInMilli;

    long elapsedSeconds = different / secondsInMilli;

    String days=String.valueOf(elapsedDays);
    String hours=String.valueOf(elapsedHours);
    String minutes=String.valueOf(elapsedMinutes);
    String seconds=String.valueOf(elapsedSeconds);

 /*  if(elapsedSeconds>59)
       return minutes;
    else if(elapsedMinutes>59)
        return hours;
    else if(elapsedHours>24)
        return days;
    else*/
        return seconds;
}


private void showPopupMenu(View view, final int position, final Movie movie) {
    PopupMenu popup = new PopupMenu(context, view);
    MenuInflater inflater = popup.getMenuInflater();
    inflater.inflate(R.menu.movie_menu, popup.getMenu());
    popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
        @Override
        public boolean onMenuItemClick(MenuItem item) {
            switch (item.getItemId()) {
                case R.id.action_edit:
                    listener.onUpdate(movie);
                    notifyDataSetChanged();
                    return true;
                case R.id.action_delete:
                    listener.onDelete(movie, position);
                    return true;
                default:
            }
            return false;
        }
    });
    popup.show();
}

@Override
public int getItemCount() {
    return movies.size();
}
}

我一直在寻找很长一段时间但未能找到解决方案。 有谁知道我在这做错了什么？

Answer 1

您正在使用错误的模式，这会导致异常，并且diff将作为空蜇返回，因此您可以使用

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss");

    try {
        Date date1 = simpleDateFormat.parse(currentTime);
        Date date2 = simpleDateFormat.parse(saveTime);

即使是更好的解决方案，使用

DateFormat df = DateFormat.getDateTimeInstance();    
    try {
        Date date1 = df.parse(currentTime);
        Date date2 = df.parse(saveTime);

Answer 2

我完全不明白，但希望所以这可能在您的节点中工作，保存当前日期为

long currentDateTime=new Date().getTime();

然后在你的getTimeDifference方法

private String getTimeDifference(){
   long difference=new Date().getTime()-movie.getCurrentDateTime();
   DateFormat formatter = new SimpleDateFormat("HH:mm:ss:SSS");
   return formatter.format(new Date(difference));
}