Salesforce Pagination Demo

CustomIterable.cls

global class CustomIterable implements Iterator<List<RecordWrapper>> {
    // NOTE: 'Record' should be replaced with the API name of the object you want to have
    // pagination for.
    
    // The Iterator interface is used for pagination
    List<RecordWrapper>InnerList {get; set;}
    // Holds all the values
    List<RecordWrapper>ListRequested {get; set;}
    // Holds the value to be displayed on the Page
    Integer i {get; set;}
    public Integer setPageSize {get; set;}

    // Constructor
    public CustomIterable(List<RecordWrapper>lstAccWr) {
        InnerList = new List<RecordWrapper>();
        ListRequested = new List<RecordWrapper>();
        InnerList = lstAccWr;
        setPageSize = 10;
        i = 0;
    }

    global boolean hasNext() {
        if (i >= InnerList.size()) {
            return false;
        } else {
            return true;
        }
    }

    global boolean hasPrevious() {
        if (i <= setPageSize) {
            return false;
        } else {
            return true;
        }
    }

    global List<RecordWrapper> next() {
        ListRequested = new List<RecordWrapper>();
        Integer startNumber;
        Integer size = InnerList.size();
        if (hasNext()) {
            if (size <= (i + setPageSize)) {
                startNumber = i;
                i = size;
            } else {
                i = (i + setPageSize);
                startNumber = (i - setPageSize);
            }
            for (Integer start = startNumber; start < i; start++) {
                ListRequested.add(InnerList[start]);
            }
        }
        return ListRequested;
    }

    global List<RecordWrapper> previous() {
        ListRequested = new List<RecordWrapper>();
        Integer size = InnerList.size();
        if (i == size) {
            if (math.mod(size, setPageSize) > 0) {
                i = size - math.mod(size, setPageSize);
            } else {
                i = (size - setPageSize);
            }
        } else {
            i = (i - setPageSize);
        }
        for(Integer start = (i - setPageSize); start < i; ++start) {
            ListRequested.add(InnerList[start]);
        }
        return ListRequested;
    }
}

CustomPaginationDemo.cls

public without sharing class CustomPaginationDemo {
    // NOTE: 'Record' should be replaced with the API name of the object you want to have
    // pagination for.

    public List<ContactWrapper> lstWrapper {get; set;}
    // Wrapper list to hold all the values
    public List<ContactWrapper> lstSetController {get; set;}
    // Wrapper list to hold the values which are displayed on UI
    public static String compareField {get; set;}
    // Holds the value of field on which the list needs to be sorted
    public static String sortOrder {get; set;}
    // Sorting order (ASC/DESC)

    CustomIterable obj;
    // Instance of Iterator

    // Constructor
    public CustomPaginationDemo() {
        lstWrapper = new List<RecordWrapper>();
        lstSetController = new List<RecordWrapper>();

        List<Record> lstRecord = [SELECT Id, Name FROM Record LIMIT 20];
        // Generating the list of records

        for (Record r : lstRecord) {
            lstWrapper.add(new RecordWrapper(rec, false));
            // Adding the values to wrapper
        }

        obj = new CustomIterable(lstWrapper);
        //Initializing the iterator
        if(lstWrapper.size() > 5) {
            obj.setPageSize = 5;
        } else {
            obj.setPageSize = lstWrapper.size() ;
        }
        // Table size
        next();
    }
    
    public Boolean hasNext {
        get {
            return obj.hasNext();
        }
        set;
    }

    public Boolean hasPrevious {
        get {
            return obj.hasPrevious();
        }
        set;
    }

    public void next() {
        lstSetController = obj.next();
    }

    public void previous() {
        lstSetController = obj.previous();
    }

    // Method used to sort
    public void sortWrpLst() {
        ContactWrapper.compareField = compareField;
        // Assigning values to ContactWrapper for Sorting
        ContactWrapper.sortOrder = sortOrder;
        // Assigning values to ContactWrapper for Sorting
        lstWrapper.sort();
        // Sorting th wrapper list
        obj = new CustomIterable(lstWrapper);
        obj.setPageSize = 5;
        next();
    }
}

CustomPaginationDemo.vfp

<apex:page controller="CustomPaginationDemo" showHeader="false" sidebar="false">
<!-- NOTE: 'Record' should be replaced with the API name of the object you want to have pagination for. -->
    <apex:form>
        <apex:pageBlock id="ThePage">
            <apex:pageBlockSection columns="1">
                <apex:pageBlockTable value="{!lstSetController}" var="obj">
                    <apex:column headerValue="Select"><apex:inputCheckbox value="{!obj.isSelected}"/></apex:column>
                    <apex:column >
                        <apex:facet name="header">
                            <apex:commandLink value="Name {!IF(compareField=='Name',IF(sortOrder='asc','▼','▲'),")}" action="{!sortWrpLst}" reRender="ThePage">
                                <apex:param name="compareField" value="Name" assignTo="{!compareField}" />
                                <apex:param name="orderType" value="{!IF(sortOrder='asc', 'desc', 'asc')}" assignTo="{!sortOrder}" />
                            </apex:commandLink>
                        </apex:facet>
                        <apex:outputField value="{!obj.cont.Name}"/>
                    </apex:column>
                </apex:pageBlockTable>
                <apex:outputPanel >
                    <apex:commandButton value="Previous" action="{!previous}" disabled="{!!hasPrevious}" reRender="ThePage" />
                    <apex:commandButton value="Next" action="{!next}" disabled="{!!hasNext}" reRender="ThePage" />
                </apex:outputPanel>
            </apex:pageBlockSection>
        </apex:pageBlock>
    </apex:form>
</apex:page>

RecordWrapper.cls

global class RecordWrapper implements Comparable {
    // NOTE: 'Record' should be replaced with the API name of the object you want to have
    // pagination for.

    // The compareble interface is used for sorting the Wrapper List
    // Wrapper Structure Strats {{{
    // this structure can be customized as per requirement
    public Boolean isSelected {get; set;}
    public Record rec {get; set;}
    // Wrapper Structure Ends }}}

    public static String compareField {get; set;}
    // Variable to hold the value of Field / Column for Sorting
    public static String sortOrder {get; set;}
    // Variable to hold the order for Sorting (ASC/DESC)

    // Constructor
    public RecordWrapper(Record rec, Boolean isSelected) {
        this.rec = rec;
        this.isSelected = isSelected;
    }

    // Compareto is a required method that is used when we implement comparable interface.
    public Integer compareTo(Object vRec) {
        RecordWrapper recToCompare = (RecordWrapper) vRec;

        if ((String) rec.get(compareField) > (String) recToCompare.rec.get(compareField)) {
            return sortOrder.equals('ASC') ? 1 : 0;
        } else {
            return sortOrder.equals('ASC') ? 0 : 1;
        }
    }
}