Sorting arraylist in android not working

Question

Im calling collections.sort on an array list of objects of class appointment but it wont sort nothing happens

This is how im calling the collections sort

 ArrayList<appointment> listoffappointments = new ArrayList<appointment>();

 //then everytime on button click user adds a new appointment after setting the following code is executed 
{
 Calendar calendar1 = Calendar.getInstance();                
 calendar1.set(mYear, mMonth, mDay, temphour, tempmin);
 appointment tempppt = new appointment(c2,tempstring1);
 listoffappointments.add(tempppt);
 Collections.sort(listoffappointments);
}

Here is the class can someone find the issue thanks

import java.util.Calendar;

public class appointment  implements Comparable<appointment> {

Calendar time;
String Text;
public appointment(Calendar tempc, String temptext) {
    Text = temptext;
    time = tempc;
}

public void settext(String text)
{
    Text = text;
}
public String gettext()
{
    return Text;
}
public String toString() {
    return Text;
}
public Long gettimeofappt()
{
    return time.getTimeInMillis();

}

@Override
public int compareTo(appointment o) {
     return (this.gettimeofappt() < o.gettimeofappt() ) ? -1: (this.gettimeofappt() > o.gettimeofappt() ) ? 1:0 ;  

}


}

in my other class that has the array list of objects of class appointment — theForgottenCoder
– theForgottenCoder, Commented Apr 4, 2014 at 8:40
assume i already have elements of type appointment in my arraylist — theForgottenCoder
– theForgottenCoder, Commented Apr 4, 2014 at 8:43

Blackbelt · Accepted Answer · 2014-04-04 08:34:14Z

2

you are returning a Long object, Change your compareTo like:

@Override
public int compareTo(appointment o) {
     return this.gettimeofappt().compareTo(o.gettimeofappt() );

}

Long.compareTo compares two Long objects numerically, and Retunrs:

the value 0 if this Long is equal to the argument Long; a value less than 0 if this Long is numerically less than the argument Long; and a value greater than 0 if this Long is numerically greater than the argument Long (signed comparison).

answered Apr 4, 2014 at 8:34

Blackbelt

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3 Comments

theForgottenCoder Over a year ago

even with "return this.gettimeofappt().compareTo(o.gettimeofappt() );" nothing changes @blackbelt

Blackbelt Over a year ago

can you print the content of the ArrayList ? Just for debugging puropse

theForgottenCoder Over a year ago

contents of array list come out exactly in order they wen in so first then first second then first second third

Lavekush · Accepted Answer · 2014-04-04 08:42:25Z

1

Try this:

Collections.sort(list, new Comparator<String>() {
        @Override
        public int compare(String s1, String s2) {
            return s1.compareToIgnoreCase(s2);
        }
    });

Look at Sorting ArrayList (String ArrayList and custom class)

answered Apr 4, 2014 at 8:42

Lavekush

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