Cancel CountDownTimer in Recyclerview

Question

I have an Recyclerview with countDownTimers which shows the time left to play in Days, Hours, Minutes and Seconds. Now I have the problem, that when I leave the activity, the countDownTimers are still running. Here is my Adapter:

Public class RvAdapterShowVsTeamChallenges extends RecyclerView.Adapter<RvAdapterShowVsTeamChallenges.ViewHolderClass> {

private Boolean boFirstTime = true;

private int [] ayColors = {R.drawable.circle_red,R.drawable.circle_purple,R.drawable.circle_orange,R.drawable.circle_blue,R.drawable.circle_tile};

private Context context;

private CountDownTimer countDownTimerTest;

private DatabaseWrite databaseWrite;

private SharedPrefs sharedPrefs;




public RvAdapterShowVsTeamChallenges(final Context context)
{
    this.context = context;
}


public class ViewHolderClass extends RecyclerView.ViewHolder{

    private TextView txtChallenger;
    private TextView txtOponnent;
    private TextView txtChallengerScore;
    private TextView txtOponnentScore;
    private TextView txtTime;

    private TextView txtChallengerLetters;
    private TextView txtOponnentLetters;

    private ProgressBar prgChallenger;
    private ProgressBar prgOponnent;



    public ViewHolderClass(View itemView) {
        super(itemView);

        sharedPrefs = new SharedPrefs(context);


        txtChallenger = (TextView) itemView.findViewById(R.id.txtChallenger);
        txtOponnent = (TextView) itemView.findViewById(R.id.txtOponnent);

        txtChallengerScore = (TextView) itemView.findViewById(R.id.txtChallengerScore);
        txtOponnentScore = (TextView) itemView.findViewById(R.id.txtOponnentScore);

        txtChallengerLetters = (TextView)itemView.findViewById(R.id.txtChallengerLetter);
        txtOponnentLetters = (TextView)itemView.findViewById(R.id.imgOponnent);

        txtTime = (TextView) itemView.findViewById(R.id.txtTime);


        prgChallenger = (ProgressBar) itemView.findViewById(R.id.prgTimeLeft);
        prgOponnent = (ProgressBar) itemView.findViewById(R.id.prgOponnent);




    }
}



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

    View itemview1 = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_show_vs_team_challenges,null);


    if(boFirstTime)
    {
        for(int i=0; i<ShowVsTeam.ayListTimeLeftChallenge.size(); i++)
        {
            long substractFalseValue =  ((ShowVsTeam.ayListTimeLeftChallenge.get(i)-1209600033)/1000);

            long total = ((substractFalseValue + 1209600)*1000);

            long difference = (total - System.currentTimeMillis());
            ShowVsTeam.ayListTimeLeftChallenge.set(i, difference);
        }

        boFirstTime = false;
    }


    countDownTimerTest = new CountDownTimer(1800000,1000) {
        @Override
        public void onTick(long millisUntilFinished) {

            for(int i=0; i<ShowVsTeam.ayListTimeLeftChallenge.size(); i++)
            {
                long lngUntilNow = ShowVsTeam.ayListTimeLeftChallenge.get(i);

                long lngNow = (lngUntilNow-(1000/ShowVsTeam.ayListTimeLeftChallenge.size()));

                ShowVsTeam.ayListTimeLeftChallenge.set(i, Long.valueOf(lngNow));
            }

            notifyDataSetChanged();
        }

        @Override
        public void onFinish() {

        }
    }.start();



    return new ViewHolderClass(itemview1);
}

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


    holder.txtChallenger.setText(sharedPrefs.getTeamnameServer(context));
    holder.txtOponnent.setText(ShowVsTeam.aylistOponnentTeamsChallenge.get(position));

    holder.txtChallengerScore.setText(ShowVsTeam.ayListScoreChallengerChallenge.get(position));
    holder.txtOponnentScore.setText(ShowVsTeam.ayListScoreOppnnentChallenge.get(position));

    String strLetterChallenger = sharedPrefs.getTeamnameServer(context).substring(0,1);
    String strLetterOpponnent = ShowVsTeam.aylistOponnentTeamsChallenge.get(position).substring(0,1);


    holder.txtChallengerLetters.setText(strLetterChallenger);
    holder.txtOponnentLetters.setText(strLetterOpponnent);
    holder.txtOponnentLetters.setBackgroundResource(ayColors[position]);

    holder.prgChallenger.setProgress(Integer.parseInt(ShowVsTeam.ayListScoreChallengerChallenge.get(position)));
    holder.prgOponnent.setProgress(Integer.parseInt(ShowVsTeam.ayListScoreOppnnentChallenge.get(position)));


    long seconds = TimeUnit.MILLISECONDS.toSeconds(ShowVsTeam.ayListTimeLeftChallenge.get(position));
    int intDay = (int)TimeUnit.SECONDS.toDays(seconds);
    long lngHours = TimeUnit.SECONDS.toHours(seconds) - (intDay *24);
    long lngMinutes = TimeUnit.SECONDS.toMinutes(seconds) - (TimeUnit.SECONDS.toHours(seconds)* 60);
    long lngSeconds = TimeUnit.SECONDS.toSeconds(seconds) - (TimeUnit.SECONDS.toMinutes(seconds) *60);

    holder.txtTime.setText(String.valueOf(intDay)+"d:"+String.valueOf(lngHours)+"h:"+String.valueOf(lngMinutes)+"m:"+String.valueOf(lngSeconds)+"s");

}


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


}

I tried to cancel the CountDownTimer onStop() in my Activity but I get a Nullpointer, although the countDownTimers are still running.

In Adapter

public void finishTimer(){
    if(countDownTimerTest!=null){
        countDownTimerTest.cancel();
    }
}

In Activity

    @Override
protected void onStop() {

    if(rvAdapterShowVsTeamChallenges!=null){
        rvAdapterShowVsTeamChallenges.finishTimer();
    }

    super.onStop();
    }
}

Can you help me?

UPDATE

ADAPTER

public class RvAdapterShowVsTeamChallenges extends RecyclerView.Adapter<RvAdapterShowVsTeamChallenges.ViewHolderClass> {

private Boolean boFirstTime = true;

private int [] ayColors = {R.drawable.circle_red,R.drawable.circle_purple,R.drawable.circle_orange,R.drawable.circle_blue,R.drawable.circle_tile};

private Context context;


private DatabaseWrite databaseWrite;

private SharedPrefs sharedPrefs;

private CountDownTimerTest countDownTimerTest;


public RvAdapterShowVsTeamChallenges(final Context context)
{
    this.context = context;
}


public class ViewHolderClass extends RecyclerView.ViewHolder{

    private TextView txtChallenger;
    private TextView txtOponnent;
    private TextView txtChallengerScore;
    private TextView txtOponnentScore;
    private TextView txtTime;

    private TextView txtChallengerLetters;
    private TextView txtOponnentLetters;

    private ProgressBar prgChallenger;
    private ProgressBar prgOponnent;



    public ViewHolderClass(View itemView) {
        super(itemView);

        sharedPrefs = new SharedPrefs(context);


        txtChallenger = (TextView) itemView.findViewById(R.id.txtChallenger);
        txtOponnent = (TextView) itemView.findViewById(R.id.txtOponnent);

        txtChallengerScore = (TextView) itemView.findViewById(R.id.txtChallengerScore);
        txtOponnentScore = (TextView) itemView.findViewById(R.id.txtOponnentScore);

        txtChallengerLetters = (TextView)itemView.findViewById(R.id.txtChallengerLetter);
        txtOponnentLetters = (TextView)itemView.findViewById(R.id.imgOponnent);

        txtTime = (TextView) itemView.findViewById(R.id.txtTime);


        prgChallenger = (ProgressBar) itemView.findViewById(R.id.prgTimeLeft);
        prgOponnent = (ProgressBar) itemView.findViewById(R.id.prgOponnent);

    }
}



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

    View itemview1 = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_show_vs_team_challenges,null);


    if(boFirstTime)
    {
        for(int i=0; i<ShowVsTeam.ayListTimeLeftChallenge.size(); i++)
        {
            long substractFalseValue =  ((ShowVsTeam.ayListTimeLeftChallenge.get(i)-1209600033)/1000);

            long total = ((substractFalseValue + 1209600)*1000);

            long difference = (total - System.currentTimeMillis());
            ShowVsTeam.ayListTimeLeftChallenge.set(i, difference);
        }

        boFirstTime = false;
    }


    return new ViewHolderClass(itemview1);
}

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


    holder.txtChallenger.setText(sharedPrefs.getTeamnameServer(context));
    holder.txtOponnent.setText(ShowVsTeam.aylistOponnentTeamsChallenge.get(position));

    holder.txtChallengerScore.setText(ShowVsTeam.ayListScoreChallengerChallenge.get(position));
    holder.txtOponnentScore.setText(ShowVsTeam.ayListScoreOppnnentChallenge.get(position));

    String strLetterChallenger = sharedPrefs.getTeamnameServer(context).substring(0,1);
    String strLetterOpponnent = ShowVsTeam.aylistOponnentTeamsChallenge.get(position).substring(0,1);


    holder.txtChallengerLetters.setText(strLetterChallenger);
    holder.txtOponnentLetters.setText(strLetterOpponnent);
    holder.txtOponnentLetters.setBackgroundResource(ayColors[position]);

    holder.prgChallenger.setProgress(Integer.parseInt(ShowVsTeam.ayListScoreChallengerChallenge.get(position)));
    holder.prgOponnent.setProgress(Integer.parseInt(ShowVsTeam.ayListScoreOppnnentChallenge.get(position)));


    long seconds = TimeUnit.MILLISECONDS.toSeconds(ShowVsTeam.ayListTimeLeftChallenge.get(position));
    int intDay = (int)TimeUnit.SECONDS.toDays(seconds);
    long lngHours = TimeUnit.SECONDS.toHours(seconds) - (intDay *24);
    long lngMinutes = TimeUnit.SECONDS.toMinutes(seconds) - (TimeUnit.SECONDS.toHours(seconds)* 60);
    long lngSeconds = TimeUnit.SECONDS.toSeconds(seconds) - (TimeUnit.SECONDS.toMinutes(seconds) *60);

    holder.txtTime.setText(String.valueOf(intDay)+"d:"+String.valueOf(lngHours)+"h:"+String.valueOf(lngMinutes)+"m:"+String.valueOf(lngSeconds)+"s");

}


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


private class CountDownTimerTest extends CountDownTimer {

    private CountDownTimerTest(long millis, long interval) {
        super(millis, interval);
    }

    @Override
    public void onTick(long millisUntilFinished) {

        for(int i=0; i<ShowVsTeam.ayListTimeLeftChallenge.size(); i++)
        {
            long lngUntilNow = ShowVsTeam.ayListTimeLeftChallenge.get(i);

            long lngNow = (lngUntilNow-(1000/ShowVsTeam.ayListTimeLeftChallenge.size()));

            ShowVsTeam.ayListTimeLeftChallenge.set(i, Long.valueOf(lngNow));
        }

        notifyDataSetChanged();

    }

    @Override
    public void onFinish() {


    }
}


public void startTimer(){

    if(countDownTimerTest==null){
        countDownTimerTest= new CountDownTimerTest(1800000,1000);
    }

    countDownTimerTest.start();
}


public void cancelTimer(){

    countDownTimerTest.cancel();
    }

}

Activity

public class ShowVsTeam extends AppCompatActivity {

public int intTextBo = 0;

private String  strMethod;

static ArrayList<String> ayListChallengerTeamsRequest;
static ArrayList<String> ayListChallengerPlayedRequest;
static ArrayList<String> ayListChallengerNumberOfMembersRequest;
static ArrayList<String> ayListChallengerAcceptedRequest;
static ArrayList<String> ayListOponnentTeamsRequest;
static ArrayList<String> ayListOponnnetPlayedRequest;
static ArrayList<String> ayListOponnentNumberOfMembersRequest;

static ArrayList<String> ayListOnlyChallengerTeamsRequest;
static ArrayList<String> ayListOnlyAcceptedRequest;
static ArrayList<String> ayListOnlyRequiredRequest;


static ArrayList<String> aylistOponnentTeamsChallenge;
static ArrayList<String> ayListScoreChallengerChallenge;
static ArrayList<String> ayListScoreOppnnentChallenge;

static ArrayList<Long> ayListTimeLeftRequestChallenger;
static ArrayList<Long> ayListTimeLeftRequestOponnent;
static ArrayList<Long> ayListTimeLeftChallenge;


private TextView txtToolbarTitle;
static TextView txtNo;

private Toolbar toolbar;


private RecyclerView recyclerViewRequests;
private RecyclerView.Adapter rvAdapterRequests;
private RecyclerView.LayoutManager rvLayoutManagerRequests;

private RecyclerView recyclerViewChallenges;
private RecyclerView.Adapter rvAdapterChallenges;
private RecyclerView.LayoutManager rvLayoutManagerChallenges;

private RvAdapterShowVsTeamChallenges rvAdapterShowVsTeamChallenges;


private SharedPrefs sharedPrefs;
private DatabaseWrite databaseWrite;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    requestWindowFeature(Window.FEATURE_NO_TITLE);
    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.show_vs_team);

    initialize();
    declare();
    navigation();
    getVS();
}

private void initialize() {

    txtNo = (TextView)findViewById(R.id.txtNo);

    toolbar = (Toolbar)findViewById(R.id.toolbar);
    txtToolbarTitle = (TextView)toolbar.findViewById(R.id.txtToolbarTitle);


    recyclerViewRequests = (RecyclerView)findViewById(R.id.recyclerShowVsTeamRequests);
    rvLayoutManagerRequests = new LinearLayoutManager(this);
    rvAdapterRequests = new RvAdapterShowVsTeamRequests(this);


    recyclerViewChallenges = (RecyclerView)findViewById(R.id.recyclerShowVsTeamChallenges);
    rvLayoutManagerChallenges  = new LinearLayoutManager(this);
    rvAdapterChallenges  = new RvAdapterShowVsTeamChallenges(this);

    rvAdapterShowVsTeamChallenges = new RvAdapterShowVsTeamChallenges(this);

    sharedPrefs = new SharedPrefs(this);


}

 private void declare() {

     recyclerViewRequests.setLayoutManager(rvLayoutManagerRequests);
     recyclerViewChallenges.setLayoutManager(rvLayoutManagerChallenges);

}


private void navigation() {

    txtToolbarTitle.setText("BeforeTeam");

    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayShowTitleEnabled(false);
}


private void getVS()
{
    strMethod = "showVsTeamRequests";

    databaseWrite = new DatabaseWrite(this);
    databaseWrite.passTheClassShowVsTeam(this);
    databaseWrite.execute(strMethod,sharedPrefs.getTeamnameServer(this));


    strMethod = "showVsTeamChallenges";

    databaseWrite = new DatabaseWrite(this);
    databaseWrite.passTheClassShowVsTeam(this);
    databaseWrite.execute(strMethod,sharedPrefs.getTeamnameServer(this));
}


public void showVsTeamRequests()
{
    recyclerViewRequests.setAdapter(rvAdapterRequests);


}

public void showVsteamChallenges()
{
    recyclerViewChallenges.setAdapter(rvAdapterChallenges);
    rvAdapterShowVsTeamChallenges.startTimer();
}


@Override
public void onBackPressed() {
    super.onBackPressed();

    rvAdapterShowVsTeamChallenges.cancelTimer();
}

@Override
protected void onStop() {
    super.onStop();

    rvAdapterShowVsTeamChallenges.cancelTimer();
}

@Override
protected void onPause() {
    super.onPause();

    rvAdapterShowVsTeamChallenges.cancelTimer();
    }
}

Answer 1

I was actually using the onViewDetachedFromWindow and onViewAttachedFromWindow functions. However, when the activity destroyed, I saw that the onViewRecycled function works one time. These codes worked for me perfectly:

Add onViewRecycled to your RecycleViewAdapter

@Override
public void onViewRecycled(@NonNull ViewHolder holder) {
    super.onViewRecycled(holder);
    //add cancel function
    if (holder.timer != null) {
        holder.timer.cancel();
    }
}

After that, add onDestroy to your Activity

@Override
protected void onDestroy() {
    super.onDestroy();
    //set adapter
    recylerView.setAdapter(null);
}