Let me start with the following example:
public void loadList(ArrayList<Calls> list) {
List<Calls> calls = new ArrayList<Calls>();
calls.addAll(list);
}
where Calls is a simple class:
public class Calls {
public long ms;
public name;
}
I want to sort the List<Calls> above in ascending or descending order based on the ms field. I came across some examples of Comparator but still am not clear through.
I guess this would help
public void loadList(ArrayList<Calls> list) {
List<Calls> calls = new ArrayList<Calls>();
calls.addAll( list );
// Ascending Order
Collections.sort(calls, new Comparator<Calls>() {
@Override
public int compare(Calls o1, Calls o2) {
return (int)(o1.ms-o2.ms);
}
});
// Descending Order
Collections.sort(calls, new Comparator<Calls>() {
@Override
public int compare(Calls o1, Calls o2) {
return (int)(o2.ms-o1.ms);
}
});
}
see following example
class CallsComp implements Comparator<Calls>{
@Override
public int compare(Calls c1, Calls c2) {
if(c1.getMs() < c2.getMs()){
return 1;
} else {
return -1;
}
}
}
just implement a Comparator this way:
private class CallsComparator implements Comparator<Calls> {
@Override
public int compare(Calls calls1, Calls calls2) {
//Swap calls1 with 2
return 1;
//Spap 2 with 1
return -1;
// do nothing
return 0;
}
}
of course you have to replace my comments with an if-condition :-)
and execute the comparator with:
Collections.sort(calls, new CallsComparator());
The Calls class need to implement the Comparable interface and implement the compareTo method:
public class Calls implements Comparable<Calls> {
public long ms;
public name;
@Override
public int compareTo(Calls call) {
// Prepend a -1 for inverse order
return Long.compare(this.ms,call.ms);
}
}
Then just call Collections.sort(calls) to sort your list.
class MSComaparator implements Comparator<Calls>{
@Override
public int compare(Calls lhs, Calls rhs) {
// TODO Auto-generated method stub
return lhs.ms-rhs.ms;
}
}
class NameComaparator implements Comparator<Calls>{
@Override
public int compare(Calls lhs, Calls rhs) {
// TODO Auto-generated method stub
return lhs.name.comapreTo(rhs.name);
}
}
and call:
public void loadList(ArrayList<Calls> list) {
List<Calls> calls = new ArrayList<Calls>();
calls.addAll(list);
Collections.sort(calls,new MSComaparator())
}
if you just want to sort based on ns you can simple implement Comparable:
public class Calls implements Comparable<Calls>{
public long ms;
public name;
@Override
public int compareTo(Calls another) {
// TODO Auto-generated method stub
return this.ms>another.ms;
}
}
And call:
public void loadList(ArrayList<Calls> list) {
List<Calls> calls = new ArrayList<Calls>();
calls.addAll(list);
Collections.sort(calls)
}
@ARP
I know its too late to answer this question but I have implemented same thing in my project recently so thought i should share with you
so inside your function after adding list what you can do is
public void loadList(ArrayList<Calls> list) {
List<Calls> calls = new ArrayList<Calls>();
calls.addAll(list);
Collections.sort(calls, new Comparator<Calls>() {
@Override
public int compare(Calls o, Calls t1) {
return (int) (o.getMS() - t1.getMS());
}
});
}
This will sort ArrayList<Calls> call for you based on the value present in ms
.
