How to change text based on time and date?

Question

So I need one of two options but don't know where to start with either.

• I have a list card views in a recyclerview. Each card view needs to have countdown timer implemented and able to run simultaneously. (Seems like the harder option) OR

• Update the text in a card view based on if a specified time has elapsed or system time reaches a specified minute and hour.

Answer 1

To make the cards with different timers you will need threads. And the easiest way in Android is AsyncTask. So you create a bunch of AsyncTasks (probably you'd want an ArrayList to which you will add the AsyncTasks) and then with a cycle simply .execute() them.

Making an AsyncTask is very easy. You simply make a new class that is derived from AsyncTask and implement the doInBackground() method.

P.S. If you're developing for Android 3.0 and higher you will need to launch AsyncTasks this way:

.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);

This will make them run simultaneously

Answer 2

UPDATE

As stated by others in other posts you have to know when to start and stop the timer because this is making you problems. I manged to make this work without canceling the recycler so here is my code. Hope it helps. Any feedback is appreciated.

public class ViewHolderContentCard extends RecyclerView.ViewHolder {

public TextView cardTv;
public CountdownUtils countdownUtils;

public ViewHolderContentCard(final View itemView) {
    super(itemView);

    cardTv = (TextView) itemView.findViewById(R.id.cardCountDownTvID);

    countdownUtils = new CountdownUtils(cardTv);
}}

 public class ContentRecyclerAdapterCard extends RecyclerView.Adapter<ViewHolderContentCard> {
private ArrayList<Content> mContentArrayList;

public ContentRecyclerAdapterCard(ArrayList<Content> contentArrayList) {

    this.mContentArrayList = contentArrayList;

}

@Override
public ViewHolderContentCard onCreateViewHolder(ViewGroup parent, int viewType) {

    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.cardview_content, parent, false);

    ViewHolderContentCard viewHolderContentCard = new ViewHolderContentCard(view);
    return viewHolderContentCard;
}

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

    holder.cardTextTv.setText(mContentArrayList.get(position).getmTitle());

    //update count down
    holder.countdownUtils.updateCountdownTv(mContentArrayList.get(position));
}

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

public class CountdownUtils {

private TextView mTextView;
private CountDownTimer mTimer;

public CountdownUtils(TextView textView) {
    mTextView = textView;
}

public void updateCountdownTv(Content content) {

    //cancel old timer to make sure one timer is updating one card
    cleanUpTimer();

    //get beginning and expiration period
    String dateFrom = content.getmDateFrom();
    String dateTo = content.getmDateTo();
    String timeFrom = content.getmTimeFrom();
    String timeTo = content.getmTimeTo();

    //process dates and update the countdown
    processCountDownAndUpdateUI(mTextView, dateFrom, dateTo, timeFrom, timeTo);
}

private void processCountDownAndUpdateUI(final TextView textView, String dateFrom, String dateTo, String timeFrom, String timeTo) {

    try {
        //format date and time
        Date beginningPeriod = getDateFromString(dateFrom, timeFrom);
        Date expirationPeriod = getDateFromString(dateTo, timeTo);

        //check beginning period with current time
        if (System.currentTimeMillis() < beginningPeriod.getTime()) {

            //we know that the is not available yet so display staring period - update the UI
            textView.setText("Starting from: " + dateFrom + " " + timeFrom);

        } else if (expirationPeriod.getTime() > System.currentTimeMillis()) {

            long availabilityPeriod = getAvailabilityPeriod(expirationPeriod);

            if (availabilityPeriod != 0) {
                //we have a valid avilability period so we need to start the countdown - update the UI
                startCountDownTimer(textView, availabilityPeriod);
            }
        }
    } catch (ParseException e) {
        e.printStackTrace();
    }
}

private void startCountDownTimer(final TextView textView, long availabilityPeriod) {

    //create countdown timer, count each second
    mTimer = new CountDownTimer(availabilityPeriod, 1000) {

        @Override
        public void onTick(long millisUntilFinished) {

            //format string will be displayed
            String timeSting = String.format("%d days %02d:%02d:%02d",
                    TimeUnit.MILLISECONDS.toDays(millisUntilFinished),
                    TimeUnit.MILLISECONDS.toHours(millisUntilFinished) - TimeUnit.DAYS.toHours(TimeUnit.MILLISECONDS.toDays(millisUntilFinished)),
                    TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millisUntilFinished)),
                    TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished)));

            //display countdown
            textView.setText(timeSting);
        }

        @Override
        public void onFinish() {

            //expired inform the user
            textView.setText("Expired");
        }
    }.start();
}

private long getAvailabilityPeriod(Date periodFrom) {

    long availabilityPeriod = 0;

    //get expiration date as long
    long expPeriod = periodFrom.getTime();

    //check availability period
    if (expPeriod > System.currentTimeMillis()) {
        availabilityPeriod = expPeriod - System.currentTimeMillis();
    }

    return availabilityPeriod;
}

private Date getDateFromString(String date, String time) throws ParseException {

    //extract data as date and time
    Date formattedDate = new SimpleDateFormat("yyyy/MM/dd HH:mm").parse(date + " " + time);

    return formattedDate;
}

public void cleanUpTimer() {
    if (mTimer != null){
        mTimer.cancel();
    }    }}