Chronometer Countdown In Android

I have implemented a simple chronometer from the android api demo. Now is it possible to show the countdown in chronometer like setting the start to 01:23 then onClick of start but

Solution 1:

For those who are interested, take a look at CountDownTimer class.

Example:

new CountDownTimer(30000, 1000) {

 publicvoidonTick(long millisUntilFinished) {
     mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
 }

 publicvoidonFinish() {
     mTextField.setText("done!");
 }
}.start();

Solution 2:

Here is my class Clock for clock and date showing. Change it for count down.

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import android.os.Handler;
import android.widget.TextView;
/**
 * The class for creating and refreshing many different fields on different layouts,
 * that can hold actual time and/or date in different formats 
 * The formats should be as in http://developer.android.com/reference/java/text/SimpleDateFormat.html. 
 * Only present and visible fields are being actualized, so there is no need to clean the clock list after closing an activity
 * 
 * Examples of use:
 * 
 *      Clock.registerClock((TextView) findViewById(R.id.TimeField), "HH:mm");
 *      Clock.registerClock((TextView) findViewById(R.id.DateField), "d.M.yyyy EEE");
 *      Clock.start(10000L);
 *
 * @author Petr Gangnus
 */publicfinalclassClock {
    /**
     * the handler that works instead of timer and supports UI
     */staticprivateHandlerhandler=newHandler();
    /**
     * the interval of the time refreshing
     */staticprivatelong refreshStep;

    /**
     * pairs TextView clockFace + time/date format
     */private TextView clockFace;
    private String format;
    privateClock(TextView clockFace, String format){
        this.clockFace=clockFace;
        this.format=format;
    }
    // here is the list of views containing the visual timers that should be held actualstaticprivate ArrayList<Clock> clocks=newArrayList<Clock>();
    /**
     * fills all timer fields by actual time value, according to their formats.
     */staticprivateRunnablemUpdateTimeTask=newRunnable() {
       publicvoidrun() {
           for(Clock clock:clocks){
               showActualTimeDate(clock);
           }
           handler.postDelayed(this,refreshStep);
       }
    };

    //============================================ public members ====================================================================/**
     * add a clock to the list of updating clocks
     * @param clockFace - the place where the time or date will be shown 
     * @param format - the format of the time/date 
     * @return
     */publicstaticbooleanregisterClock(TextView clockFace, String format){
        if (clockFace==null) returnfalse;
        if(clocks.contains(clockFace)){
            // old clockFace
            clocks.get(clocks.indexOf(clockFace)).format=format;
        } else {
            // new clockFace
            clocks.add(newClock(clockFace, format));
        }
        returntrue;
    }
    /**
     * remove a clock from the updating list
     * @param clockFace
     * @return
     */publicstaticbooleanunRegisterClock(TextView clockFace){
        if (clockFace==null) returnfalse;
        if(clocks.contains(clockFace)){
            // found clockFace
            clocks.remove(clocks.indexOf(clockFace));
        } else {
            // not found clockFacereturnfalse;
        }
        returntrue;
    }
    /**
     * put in the "place" the actual date/time in the appropriate "format"
     * @param place
     * @param format
     */publicstaticvoidshowActualTimeDate(Clock clock){
        if (clock.clockFace==null) return;
        if (clock.clockFace.getVisibility()!=TextView.VISIBLE) return;
        Date thisDate=newDate();
        SimpleDateFormat df=newSimpleDateFormat(clock.format);
        clock.clockFace.setText(df.format(thisDate));
    }
    /**
     * start the ticking for all clocks
     * @param step the tick interval
     */publicstaticvoidstart(long step) { 
        refreshStep=step;
        handler.removeCallbacks(mUpdateTimeTask);
        handler.postDelayed(mUpdateTimeTask, 0);
    }
    /**
     * Stopping ticking all clocks (not removing them)
     * the calling could be put somewhere in onStop
     */publicstaticvoidstop() { 
        handler.removeCallbacks(mUpdateTimeTask);
    }
}