android - 来自具有日期差异的firebase数据库的android倒数计时器

Question

我想通过从 firebase 数据库获取结束日期字符串来为 android 制作倒数计时器。当我尝试将结束日期字符串作为简单变量时，它可以工作，但是当我从 firebase 数据库中获得完全相同的日期字符串时，它不起作用或者我不知道该怎么办。这是我的代码

public class DashboardFragment extends Fragment {
  private View dashboardFragment;
 private DatabaseReference timeRef;
public  String END_TIME="";
 private TextView days, hour, minute,second;
  private CountDownTimer mCountDownTimer;
   private long mTimeLeftInMillis;
  @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        dashboardFragment= inflater.inflate(R.layout.fragment_dashboard, container, false);
 linear_layout_1 = dashboardFragment.findViewById(R.id.linear_layout_1);
        linear_layout_2 = dashboardFragment.findViewById(R.id.linear_layout_2);
        days = dashboardFragment.findViewById(R.id.days);
        hour = dashboardFragment.findViewById(R.id.hour);
        minute = dashboardFragment.findViewById(R.id.minute);
        second = dashboardFragment.findViewById(R.id.second);

 timeRef=FirebaseDatabase.getInstance().getReference().child("Time");
   mTimeLeftInMillis=dateFormat();
     ValueEventListener timeEvent=new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {
                if (snapshot.exists()){
                    END_TIME =snapshot.child("endTime").getValue(String.class);
                  
            
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        };
        timeRef.addListenerForSingleValueEvent(timeEvent);


startTimer();

         return dashboardFragment;

    }

 private  long dateFormat() {
        long diff=0;
        SimpleDateFormat formatter=new SimpleDateFormat("dd.MM.yyyy, HH:mm");
        formatter.setLenient(false);
        String endTime_=END_TIME;
        long endTime=0;
        Date endDate;
        try {

            endDate=formatter.parse(endTime_);
            endTime= Objects.requireNonNull(endDate).getTime();
        }catch ( ParseException e){
            e.printStackTrace();
        }
        long startTime = System.currentTimeMillis();
        diff=endTime-startTime;
        return diff;
    }

    private void startTimer() {



     mCountDownTimer= new CountDownTimer(mTimeLeftInMillis, 1000) {
             @Override
             public void onTick(long millisUntilFinished) {
               mTimeLeftInMillis = millisUntilFinished;

                       long Days = mTimeLeftInMillis / (24 * 60 * 60 * 1000);
                       long Hours = mTimeLeftInMillis / (60 * 60 * 1000) % 24;
                       long Minutes = mTimeLeftInMillis / (60 * 1000) % 60;
                       long Seconds = mTimeLeftInMillis / 1000 % 60;
                       //
                       days.setText(String.format("%02d", Days));
                       hour.setText(String.format("%02d", Hours));
                       minute.setText(String.format("%02d", Minutes));
                       second.setText(String.format("%02d", Seconds));
                       
             }

             @Override
             public void onFinish() {

             }
         };
mCountDownTimer.start();

    }

正如我之前所说的，当我设置时，

END_TIME="06.05.2021 05:56"

唯一的问题是当我从 firebase 数据库中获取相同的字符串时它不起作用。任何人都知道我非常感激的解决方案。

标签： androidfirebasefirebase-realtime-databasecountdown