If I click list button 'sync', I want to move on to the view screen of the checked record

Question

I want to check the record as shown in the next screen and move on to the checked record screen when I click the sync button.

But the screen doesn't go over and it keeps stagnating.

Here's is my Code

VisualPage code

<apex:page standardController="Proposal__c" recordSetVar="props" extensions="SyncProposal" action="{!syncProposeTest}" />

ApexClass

public class SyncProposal {
    public List<Proposal__c> selproLst;
    public String PropIds;

    public SyncProposal (Apexpages.StandardSetController cntlr) {
        selproLst = cntlr.getSelected();
        PropIds ='';
        for (Proposal__c pro : selproLst) {
            PropIds += pro.id + ',';
        }
        PropIds = PropIds.removeEnd(',');

    }

    public Pagereference syncProposeTest() {
        String returnURl = 'https://<mydomain>.com' + PropIds;
        Pagereference pg = new Pagereference (returnURl);
        pg.setRedirect (true);

        System.debug(selproLst);
        System.debug(PropIds);

        return pg;

    }
}

Thank you

Answer 1

Maybe I miss something, but the "PropIds" are not defined in method "public Pagereference syncProposeTest()"?

'https://.com' + PropIds;

Should be called as "public Pagereference syncProposeTest(String PropIds)".