Wrapper List Sorting(Column Sorting) using Comparable Interface

Comparable Interface adds sorting support for Lists that contain non-primitive types, that is, Lists of user-defined types.

Whenever we want to achieve column sorting in wrapper list then we have to implement Comparable and we should define the "compareTo" method as shown below.

Here i am querying the account object records and passing them to wrapper list for giving example. Basically a wrapper class can contain combination of different types. For all such type of things also it will work.Comparable interface is very useful for sorting wrapper list.

Class:

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public class AccountClass {

    public List<AccountWrappercls> wrapperList{get;set;}

    public string sortableField{get;set;}

    public string sortOrder{get;set;}

    public string previoussortfield{get;set;}

    public AccountClass(){

        wrapperList = new List<AccountWrappercls>();

        sortableField = 'name';

        sortOrder = 'asc';

        previoussortfield =sortableField;

        for(Account actobj:[select id,name,ActiveDate__c,ACnumber__c from Account where ActiveDate__c!=null and ACnumber__c!=null]){

                AccountWrappercls wrapObj = new AccountWrappercls(actobj.ActiveDate__c,actobj.Acnumber__c,actobj.name);

                wrapperList.add(wrapObj);

        }           

        wrapperList.sort();

    }

    public pagereference doSort(){      

        //sortorder='asc';      

        if(previoussortfield == sortableField){

            sortorder='desc';

            previoussortfield=null;

        }

        else{

            sortorder='asc';            

            previoussortfield=sortableField;

        }

        System.debug('sortableField:::'+sortableField);

        System.debug('sortOrder::'+sortOrder);

        AccountWrappercls.sortableField = sortableField;

        AccountWrappercls.sortorder = sortOrder;        

        wrapperList.sort();

        return null;

    }

}

Class Which Implements Comparable interface:

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public  class AccountWrappercls implements comparable{
  public Date createdDate {get;set;}
  public decimal num1 {get;set;}
  public String  name {get;set;}
  public static String sortableField='name';
  public static String sortOrder='asc';  
  public AccountWrappercls(Date createdDate,decimal num1,String  name){
      this.createdDate = createdDate;
      this.num1 = num1;
      this.name =name;
      //this.sortableField = sortableField;
      //this.sortOrder = sortOrder;
  }
   public  Integer compareTo(Object compareTo) {
     AccountWrappercls compWrap = (AccountWrappercls)compareTo;
     if(sortOrder == 'asc'){
    if(sortableField == 'num1'){     
            if (num1 == compWrap.num1) return 0;
          if (num1 > compWrap.num1) return 1;
          return -1;        
    }
    if(sortableField == 'name'){     
            if (name == compWrap.name) return 0;
          if (name > compWrap.name) return 1;
          return -1;        
    }
    if(sortableField == 'createdDate'){     
            if (createdDate == compWrap.createdDate) return 0;
          if (createdDate > compWrap.createdDate) return 1;
          return -1;        
    }}else{
      if(sortableField == 'num1'){     
            if (num1 == compWrap.num1) return 0;
          if (num1 > compWrap.num1) return -1;
          return 1;        
    }
    if(sortableField == 'name'){     
            if (name == compWrap.name) return 0;
          if (name > compWrap.name) return -1;
          return 1;        
    }
    if(sortableField == 'createdDate'){     
            if (createdDate == compWrap.createdDate) return 0;
          if (createdDate > compWrap.createdDate) return -1;
          return 1;        
    }
    }
    
    return null;
    }    
    
}

Visualforce Page:

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<apex:page controller="AccountClass">
 <apex:form >
  <apex:pageBlock id="pb">
   <apex:pageBlocKTable value="{!wrapperList}" var="wrapObj">
    <apex:column >
     <apex:facet name="header">
      <apex:commandLink value="Name {!IF(sortableField=='name',IF(sortOrder='asc','▼','▲'),'')}" action="{!doSort}" rerender="pb">
       <apex:param name="name" value="name" assignTo="{!sortableField}"></apex:param>
      </apex:commandLink>
     </apex:facet>
     
      <apex:outputText value="{!wrapObj.name}"/>
     
    </apex:column>
    <apex:column >
     <apex:facet name="header">
      <apex:commandLink value="Ac Number {!IF(sortableField=='num1',IF(sortOrder='asc','▼','▲'),'')}" action="{!doSort}" rerender="pb">
        <apex:param name="num1" value="num1" assignTo="{!sortableField}"></apex:param>
      </apex:commandLink>
     </apex:facet>
     
      <apex:outputText value="{!wrapObj.num1}"/>
         
    </apex:column>
    <apex:column >
     <apex:facet name="header">
      <apex:commandLink value="Date {!IF(sortableField=='createdDate',IF(sortOrder='asc','▼','▲'),'')}" action="{!doSort}" rerender="pb">
       <apex:param name="createdDate" value="createdDate" assignTo="{!sortableField}"></apex:param>
      </apex:commandLink>
     </apex:facet>
     
      <apex:outputText value="{0, date, MM/d/yyyy}">
       <apex:param value="{!wrapObj.createdDate}"/>
      </apex:outputText>
        
    </apex:column>
   </apex:pageBlocKTable>
  </apex:pageBlock>
 </apex:form>
</apex:page>                                        

Output:

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