title: Android - Want app to perform tasks every second
body: <p>I'm trying to get my countdown app to perform its function of updating my current time and date TextView and fire off its MyOnItemSelectedListener every second so that the app counts down dynamically instead of just when onCreate is initiated. If there is a more efficient method then rapidly firing off MyOnItemSelectedListener I would appreciate the criticism. </p>
  
  <pre><code>public class TheCount extends Activity {
  TextView description=null;
  TextView dates=null;
  TextView times=null;
  TextView output=null;
  TextView cDateDisplay=null;
  TextView cTimeDisplay=null;
  private int mYear;
  private int mMonth;
  private int mDay;
  private int mHour;
  private int mMinute;
  private int mSecond;
  CountdownHelper helper=null;
  String countdownId=null;
  
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.thecount);
      helper=new CountdownHelper(this);
      cTimeDisplay = (TextView)findViewById(R.id.lblCurTime);
      cDateDisplay = (TextView)findViewById(R.id.lblCurDate);
  
      final Calendar c = Calendar.getInstance();
      mYear = c.get(Calendar.YEAR);
      mMonth = c.get(Calendar.MONTH);
      mDay = c.get(Calendar.DAY_OF_MONTH);
      mHour = c.get(Calendar.HOUR_OF_DAY);
      mMinute = c.get(Calendar.MINUTE);
      mSecond = c.get(Calendar.SECOND);
  
      Spinner spinner = (Spinner) findViewById(R.id.spinner1);
      ArrayAdapter&lt;CharSequence&gt; adapter = ArrayAdapter.createFromResource(
              this, R.array.countoptions, android.R.layout.simple_spinner_item);
      adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
      spinner.setAdapter(adapter);
  
      description =(TextView)findViewById(R.id.lblDescriptFed);
      dates =(TextView)findViewById(R.id.lblDateFed);
      times =(TextView)findViewById(R.id.lblTimeFed);
      output =(TextView)findViewById(R.id.lblOutput);
  
      countdownId=getIntent().getStringExtra(MainActivity.ID_EXTRA);
      if (countdownId!=null) {
          load();
      }
  
      spinner.setOnItemSelectedListener(new MyOnItemSelectedListener());
  
      updateDisplay();
  
  }
  
  private void updateDisplay() {
      Timer timer = new Timer();
      timer.schedule(new TimerTask() {
  //@Override
  public void run() {
      updatedDisplay();
      }
  },0,1000);//Update text every second
  
  }
  
  public class MyOnItemSelectedListener implements OnItemSelectedListener {
      public void onItemSelected(AdapterView&lt;?&gt; parent, View view, int pos, long id) {
  
          if (parent.getItemAtPosition(pos).toString().equals("Normal")){
              Toast.makeText(parent.getContext(), "Countdown format is " +
                    parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();
              convertTime();
          } else if (parent.getItemAtPosition(pos).toString().equals("by Days")){
              Toast.makeText(parent.getContext(), "Countdown format " +
                        parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();
                  convertDays();
          } else if (parent.getItemAtPosition(pos).toString().equals("by Hours")){
              Toast.makeText(parent.getContext(), "Countdown format " +
                        parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();
                  convertHours();
          } else if (parent.getItemAtPosition(pos).toString().equals("by Minutes")){
              Toast.makeText(parent.getContext(), "Countdown format " +
                        parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();
                  convertMinutes();
          } else if (parent.getItemAtPosition(pos).toString().equals("by Seconds")){
              Toast.makeText(parent.getContext(), "Countdown format " +
                        parent.getItemAtPosition(pos).toString(), Toast.LENGTH_LONG).show();
                  convertSeconds();
          }
  
      }
      public void onNothingSelected(AdapterView parent) {
        // Do nothing.
      }
  }
  
  private void convertTime() {
      String dtCountdown = dates.getText().toString() + " " + times.getText().toString();
      String dtCurrent = cDateDisplay.getText().toString() + " " + cTimeDisplay.getText().toString();
      SimpleDateFormat  format = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss");  
      try {  
          Date date = format.parse(dtCountdown);
          Date dateCur = format.parse(dtCurrent);
          long diff = dateCur.getTime() - date.getTime();
  
          int timeInSeconds = (int) (diff / 1000);
          int days, hours, minutes, seconds;
          days = timeInSeconds / 86400;
          timeInSeconds = timeInSeconds - (days * 86400);
          hours = timeInSeconds / 3600;
          timeInSeconds = timeInSeconds - (hours * 3600);
          minutes = timeInSeconds / 60;
          timeInSeconds = timeInSeconds - (minutes * 60);
          seconds = timeInSeconds;
  
  
          System.out.println(date); 
          if(dateCur.compareTo(date)&gt;0){
              output.setText(String.valueOf(days) + " days " + String.valueOf(hours) +
                      " hours \n" + String.valueOf(minutes) + " minutes " + String.valueOf(seconds) + " seconds ago");
          } else {
              output.setText(String.valueOf(Math.abs(days)) + " days " + String.valueOf(Math.abs(hours)) +
                      " hours \n" + String.valueOf(Math.abs(minutes)) + " minutes " + String.valueOf(Math.abs(seconds)) + " seconds till");
          }
  
      } catch (ParseException e) {  
          // TODO Auto-generated catch block  
          e.printStackTrace();  
      }
  }
  
  private void convertDays() {
      String dtCountdown = dates.getText().toString() + " " + times.getText().toString();
      String dtCurrent = cDateDisplay.getText().toString() + " " + cTimeDisplay.getText().toString();
      SimpleDateFormat  format = new SimpleDateFormat("dd/MM/yyyy hh:mm");  
      try {  
          Date date = format.parse(dtCountdown);
          Date dateCur = format.parse(dtCurrent);
          long diff = dateCur.getTime() - date.getTime();
  
          int timeInSeconds = (int) (diff / 1000);
          int days;
          days = timeInSeconds / 86400;
  
          System.out.println(date); 
          if(dateCur.compareTo(date)&gt;0){
              output.setText(String.valueOf(days) + " days ago");
          } else {
              output.setText(String.valueOf(Math.abs(days)) + " days till");
          }
  
      } catch (ParseException e) {  
          // TODO Auto-generated catch block  
          e.printStackTrace();  
      }
  }
  
  private void convertHours() {
      String dtCountdown = dates.getText().toString() + " " + times.getText().toString();
      String dtCurrent = cDateDisplay.getText().toString() + " " + cTimeDisplay.getText().toString();
      SimpleDateFormat  format = new SimpleDateFormat("dd/MM/yyyy hh:mm");  
      try {  
          Date date = format.parse(dtCountdown);
          Date dateCur = format.parse(dtCurrent);
          long diff = dateCur.getTime() - date.getTime();
  
          int timeInSeconds = (int) (diff / 1000);
          int hours;
  
          hours = timeInSeconds / 3600;
  
          System.out.println(date); 
          if(dateCur.compareTo(date)&gt;0){
              output.setText(String.valueOf(hours) + " hours ago");
          } else {
              output.setText(String.valueOf(Math.abs(hours)) + " hours till");
          }
  
      } catch (ParseException e) {  
          // TODO Auto-generated catch block  
          e.printStackTrace();  
      }
  }
  
  private void convertMinutes() {
      String dtCountdown = dates.getText().toString() + " " + times.getText().toString();
      String dtCurrent = cDateDisplay.getText().toString() + " " + cTimeDisplay.getText().toString();
      SimpleDateFormat  format = new SimpleDateFormat("dd/MM/yyyy hh:mm");  
      try {  
          Date date = format.parse(dtCountdown);
          Date dateCur = format.parse(dtCurrent);
          long diff = dateCur.getTime() - date.getTime();
  
          int timeInSeconds = (int) (diff / 1000);
          int minutes;
  
          minutes = timeInSeconds / 60;
  
          System.out.println(date); 
          if(dateCur.compareTo(date)&gt;0){
              output.setText(String.valueOf(minutes) + " minutes ago");
          } else {
              output.setText(String.valueOf(Math.abs(minutes)) + " minutes till");
          }
  
      } catch (ParseException e) {  
          // TODO Auto-generated catch block  
          e.printStackTrace();  
      }
  }
  
  private void convertSeconds() {
      String dtCountdown = dates.getText().toString() + " " + times.getText().toString();
      String dtCurrent = cDateDisplay.getText().toString() + " " + cTimeDisplay.getText().toString();
      SimpleDateFormat  format = new SimpleDateFormat("dd/MM/yyyy hh:mm");  
      try {  
          Date date = format.parse(dtCountdown);
          Date dateCur = format.parse(dtCurrent);
          long diff = dateCur.getTime() - date.getTime();
  
          int timeInSeconds = (int) (diff / 1000);
          int seconds;
          seconds = timeInSeconds;
  
          System.out.println(date); 
          if(dateCur.compareTo(date)&gt;0){
              output.setText(String.valueOf(seconds) + " seconds ago");
          } else {
              output.setText(String.valueOf(Math.abs(seconds)) + " seconds till");
          }
  
      } catch (ParseException e) {  
          // TODO Auto-generated catch block  
          e.printStackTrace();  
      }
  }
  
  private void updatedDisplay() {
      TextView cDateDisplay=null;
      TextView cTimeDisplay=null;
      cTimeDisplay = (TextView)findViewById(R.id.lblCurTime);
      cDateDisplay = (TextView)findViewById(R.id.lblCurDate);
      cDateDisplay.setText(
          new StringBuilder()
                  // Month is 0 based so add 1
                  .append(mDay).append("/")
                  .append(mMonth + 1).append("/")
                  .append(mYear).append(" "));
      cTimeDisplay.setText(
              new StringBuilder()
                      .append(pad(mHour)).append(":")
                      .append(pad(mMinute)).append(":").append(pad(mSecond)));
  }
  
  private static String pad(int c) {
      if (c &gt;= 10)
          return String.valueOf(c);
      else
          return "0" + String.valueOf(c);
  }  
  
  private void load() {
      Cursor c=helper.getById(countdownId);
  
      c.moveToFirst();    
      description.setText(helper.getDescription(c));
      dates.setText(helper.getDate(c));
      times.setText(helper.getTime(c) + ":00");
  
      c.close();
  }
  
  @Override
  public void onDestroy() {
      super.onDestroy();
  
      helper.close();
  }
  </code></pre>
  
  <p>}</p>
  
  <p>@NamLe: This crashes the app and brings this up in the LogCat when onCreate() is called.</p>
  
  <p><code>02-23 13:19:43.540: I/System.out(11667): Sun Jun 24 00:00:00 MDT 2012
  02-23 13:19:44.500: W/dalvikvm(11667): threadid=11: thread exiting with uncaught exception (group=0x40a351f8)
  02-23 13:19:44.510: E/AndroidRuntime(11667): FATAL EXCEPTION: Timer-0
  02-23 13:19:44.510: E/AndroidRuntime(11667): android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:4039)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:709)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.view.View.requestLayout(View.java:12675)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.view.View.requestLayout(View.java:12675)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.view.View.requestLayout(View.java:12675)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.view.View.requestLayout(View.java:12675)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.view.View.requestLayout(View.java:12675)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.widget.TextView.checkForRelayout(TextView.java:6773)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.widget.TextView.setText(TextView.java:3306)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.widget.TextView.setText(TextView.java:3162)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at android.widget.TextView.setText(TextView.java:3137)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at com.pixelcrunch.crunchtime.TheCount$1.run(TheCount.java:87)
  02-23 13:19:44.510: E/AndroidRuntime(11667):    at java.util.Timer$TimerImpl.run(Timer.java:284)</code></p>