Lightning Component not updating records

Question

I need help getting my muddled-together-lightning-component to update existing records. I do not really know what I'm doing so it's a wonder I've made it this far :) My component lists all child records from a parent and allows user to select all or some and apply a new picklist value to them. But, my save button does not commit the newly chosen options to the existing records. Help!

Here are images of my component:

code (it is a lot):

cmp

    <aura:component access="global" controller="MassUpdateController" 
                implements="flexipage:availableForAllPageTypes,force:lightningQuickActionWithoutHeader,force:hasRecordId,force:hasSObjectName">
    <aura:handler name="init" value="{!this}" action="{!c.doInit}"/>
    <aura:attribute name="recordId" type="Id"/>
    <aura:attribute name="relatedItems" type="MassUpdateController.wrapItemRecord[]"/>
    <aura:attribute name="selectedItems" type="MassUpdateController.wrapItemRecord[]"/>
    <aura:attribute name="itemDecisionList" type="String[]"/>
    <aura:attribute name="selectAll" type="boolean" default="false"/>
    <aura:attribute name="selectedDecision" type="String"/>
    <aura:attribute name="RIM__c" type="Object"/>
    <aura:attribute name="RIM_Item__c" type="Object"/>
        <force:recordData aura:id="rRecord"
                  recordId="{!v.recordId}"
                  targetFields="{!v.RIM__c}"
                  layoutType="FULL"
                          mode="EDIT"/>

    <lightning:card iconName="custom:custom41" 
                    title="{! 'Item List for ' + v.RIM__c.Customer_Name__c}">     

<div class="slds-form slds-p-horizontal_medium" role="list">
<div class="slds-form__row"><div class="slds-form__item" role="listitem">
<div class="slds-form-element slds-form-element_horizontal slds-is-editing">    
      <lightning:select name="selectItem" label="Apply Decision to Selected:" value="{!v.selectedDecision}" onchange="{!c.setDcn}">
               <option text="None" value="{!v.value}"></option>
               <aura:iteration items="{!v.itemDecisionList}" var="stat">
                     <option text="{!stat}" value="{!stat}"></option>                    
               </aura:iteration>                    
       </lightning:select>
</div></div></div></div>  <!-- BEGIN TABLE JUNK -->

    <table class="slds-table">
        <thead>
            <tr class="slds-text-title_caps slds-line-height_reset">
                <th class="" style="width:10px">
                    <ui:inputCheckbox aura:id="box3" value="{!v.selectAll}" change="{!c.onCheck}"/></th>
                <th class="slds-p-around_xxx-small" scope="col"><div class="" title="Type">Type</div></th> 
                <th class="slds-p-around_xxx-small" scope="col"><div class="" title="Transaction Amount">Amount</div></th>               
                <th class="slds-p-around_xxx-small" scope="col"><div class="" title="Decision">Decision</div></th>
            </tr>
        </thead>
        <tbody>

<aura:iteration items="{!v.relatedItems}" var="itm">
<tr>
    <td><div class="" style="width:10px">
        <ui:inputCheckbox aura:id="boxPack" value="{!itm.itemSelected}"/></div>
    </td>

    <td data-label="Type">
    <div class="slds-form-element__control" title="Type">
        <p class="slds-text-body_regular">{!itm.wrapItem.Transaction_Type__c}</p>
    </div></td>

    <td data-label="Transaction Amount">
    <div class="slds-form-element__control" title="Transaction Amount">
           <p><lightning:formattedNumber value="{!itm.wrapItem.Transaction_Amount_Detail__c}" style="currency" currencyCode="USD"/></p>
    </div></td>             

    <td data-label="Decision">
        <ui:inputSelect  class="slds-select spear-select" aura:id="selectItem" value="{!itm.wrapItem.Decision__c}" updateOn="change" >    
            <aura:iteration items="{!v.itemDecisionList}" var="stat">
                <ui:inputSelectOption text="{!stat}" label="{!stat}" value="{!stat==itm.wrapItem.Decision__c}" />            
            </aura:iteration>    
        </ui:inputSelect>

<!-- aura:if isTrue="{!itm.wrapItem.status__c == ''}"><img src="https://spectatorblogs.imgix.net/files/2016/03/ex.jpg"/>
    </aura:if-->&nbsp;
    </td>               
</tr></aura:iteration></tbody><br/> </table>    <!--BEGIN BUTTONS-->

            <div align="center">
                <lightning:button variant="neutral" label="cancel" onclick="{!c.cancel}" />
                <lightning:button variant="brand" label="go" onclick="{!c.changeDcn}" /> 
            </div>

    </lightning:card>
</aura:component>

controller.js:

({
    doInit : function(component, event, helper) {
        var action = component.get("c.getAllRelatedItems");  
        action.setParams({
            "visitRecordId" : component.get("v.recordId")});
        action.setCallback(this, function(a) {            
            component.set("v.relatedItems", a.getReturnValue());});
        $A.enqueueAction(action); 
        helper.getPrepopulatedValues(component, event, helper);},

    onCheck : function(component, event, helper) {
        var selAll = component.get("v.selectAll");
        var newlst =[];    
        var allItems = component.get("v.relatedItems");
        for(var i in allItems){
            var space = allItems[i];                    
            space.itemSelected = selAll;             
            newlst.push(space);}
        component.set("v.selectedItems",newlst);
        component.set("v.relatedItems",newlst);},

    setDcn : function(component, event, helper) {
        var selcDcn = component.get("v.selectedDecision");
        var newlst =[];    
        var allItems = component.get("v.relatedItems");
        for(var i in allItems){
            var space = allItems[i];                    
            if(space.itemSelected === true){
                space.wrapItem.Decision__c = selcDcn;}
            newlst.push(space);}
        component.set("v.relatedItems",newlst);}, 
//please help! ======================================================
    changeDcn : function(component, event, helper) {
         var allItems = component.get("v.relatedItems");
         for(var i in allItems){
           var space = allItems[i];    
           //alert("Decision: " + space.wrapItem.Decision__c);
         }

         var action = component.get("c.saveDcn");
         action.setParams({"dcns":  JSON.stringify(allItems) });
         action.setCallback(this, function(response){
         var state = response.getState();
         if (state === "SUCCESS") {
            var stat = component.get("v.itemDecisionList");
            stat.push(response.getReturnValue());
            component.set("v.itemDecisionList", stat);
         }
       });
      $A.enqueueAction(action);

   },
//===================================================================    
    cancel : function (component, event, helper) {
        var action = component.get("c.getAllRelatedItems");  
        action.setParams({
            "visitRecordId" : component.get("v.recordId")});
        action.setCallback(this, function(a) {            
            component.set("v.relatedItems", a.getReturnValue());});
        $A.enqueueAction(action); 
        helper.getPrepopulatedValues(component, event, helper);
    },
})

helper:

    ({
        getPrepopulatedValues : function(component, event, helper) {
            var action = component.get("c.getDcnValues");
            action.setCallback(this, function(a) {            
                component.set("v.itemDecisionList", a.getReturnValue());
            });
            $A.enqueueAction(action);
        },
    })

controller.apxc:

public class MassUpdateController {
    @auraEnabled
    public static List<wrapItemRecord> getAllRelatedItems(Id visitRecordId){
        List<wrapItemRecord> wrapItemRecordList = new List<wrapItemRecord>();
        for(RIM_Item__c itm : [select Id, Name, RIM__r.Name, Decision__c, Transaction_Amount_Detail__c, 
                               Transaction_Type__c, RIM__r.Customer_Name__c 
                               from RIM_Item__c where RIM__c = :visitRecordId]){
            wrapItemRecordList.add(new wrapItemRecord(itm));
        }
        return wrapItemRecordList;
    }
    @auraEnabled
    public static List<String> getDcnValues(){
        List<String> options = new List<String>();
        Schema.DescribeFieldResult fieldResult = RIM_Item__c.Decision__c.getDescribe();
        List<Schema.PicklistEntry> stat = fieldResult.getPicklistValues();
        for (Schema.PicklistEntry f: stat) {
            options.add(f.getLabel());
        }
        return options;
    }
    //==================================================================
    @auraEnabled
   public static List<RIM_Item__c> saveDcn(String stat){
       List<RIM_Item__c> statList = (List<RIM_Item__c>)JSON.deserialize(stat,List<RIM_Item__c>.class); 
       UPDATE statList;
       RETURN statList;
   }
    //==================================================================

    public class wrapItemRecord{
        @auraEnabled
        public boolean itemSelected{get; set;}

        @auraEnabled
        public RIM_Item__c wrapItem{get; set;}

        @auraEnabled
        public boolean isDecided{get; set;}

        public wrapItemRecord(RIM_Item__c itm){
            itemSelected = false;
            wrapItem = itm;
            if(itm.Decision__c == null){
                isDecided = false;
            }else{
                isDecided = true;
            }
        }
    }
}

Answer 1

As your method passing list and updating and getting a single object that's the problem

Try below code APEX method.

//==================================================================
@auraEnabled
public static List<RIM_Item__c> saveDcn(List<RIM_Item__c> dcns){
    UPDATE dcns;
    RETURN dcns;
}
//==================================================================

The best way to send the stringify request structure to APEX Call as below.

 //please help! ======================================================
    changeDcn : function(component, event, helper) {
         var allItems = component.get("v.relatedItems");
         for(var i in allItems){
           var space = allItems[i];    
           //alert("Decision: " + space.wrapItem.Decision__c);
         }

         var action = component.get("c.saveDcn");
         // instead passing list you can pass stringified value and APEX 
         // method will also change accordingly
         action.setParams({"dcns":  JSON.stringify(allItems) });
         action.setCallback(this, function(response){
         var state = response.getState();
         if (state === "SUCCESS") {
            var listy = component.get("v.itemDecisionList");
            listy.push(response.getReturnValue());
            component.set("v.itemDecisionList", listy);
         }
       });
      $A.enqueueAction(action);

   }, 
  //===================================================================  

After above modification in cmp controller Below is the APEX Method change

 //==================================================================
   @auraEnabled
   public static List<RIM_Item__c> saveDcn(String dcns){
       List<RIM_Item__c> dcnsList = (List<RIM_Item__c>)JSON.deserialize(dcns,List<RIM_Item__c>.class); 
       UPDATE dcnsList;
       RETURN dcnsList;
   }
//==================================================================