<aura:component implements="forceCommunity:availableForAllPageTypes,force:hasRecordId" access="global" controller="CommunityComponentController">
<aura:attribute name="recordId" type="String" />
<aura:attribute name="edit" type="Boolean" default="true"/>
        <aura:if isTrue="{!v.edit}">
            <lightning:recordViewForm recordId="{!v.recordId}" objectApiName="Case">
                <div class="slds-grid slds-gutters_large">
                    <div class="slds-col slds-size_6-of-12">
                        <div class="slds-form-element slds-form-element_edit slds-form-element_readonly slds-hint-parent">
                            <span class="slds-form-element__label">Case Owner</span>
                            <div class="slds-form-element__control">
                                <lightning:outputField fieldName="OwnerId" variant="label-hidden" class="slds-form-element__static"/>
                            </div>
                        </div>
                    </div>
                    <div class="slds-col slds-size_6-of-12">
                        <div class="slds-form-element slds-form-element_edit slds-form-element_readonly slds-hint-parent">
                            <span class="slds-form-element__label">Parent Case</span>
                            <div class="slds-form-element__control">
                                <lightning:outputField fieldName="ParentId" variant="label-hidden" class="slds-form-element__static"/>
                            </div>
                        </div>
                    </div>
                </div>
            </lightning:recordViewForm>
            <aura:set attribute="else">
                <lightning:recordEditForm recordId="{!v.recordId}" objectApiName="Case" aura:id="recordHandler" onsuccess="{!c.toggleEdit}">
                <div class="slds-grid slds-gutters_large">
                    <div class="slds-col slds-size_6-of-12">
                        <div class="slds-form-element slds-form-element_edit slds-form-element_readonly slds-hint-parent">
                            <span class="slds-form-element__label">Case Owner</span>
                            <div class="slds-form-element__control">
                                <lightning:outputField fieldName="OwnerId" variant="label-hidden" class="slds-form-element__static"/>
                            </div>
                        </div>
                    </div>
                    <div class="slds-col slds-size_6-of-12">
                        <div class="slds-form-element slds-form-element_edit slds-form-element_readonly slds-hint-parent">
                            <span class="slds-form-element__label">Parent Case</span>
                            <div class="slds-form-element__control">
                                <lightning:outputField fieldName="ParentId" variant="label-hidden" class="slds-form-element__static"/>
                            </div>
                        </div>
                    </div>
                </div>
                    <lightning:button label="Cancel" title="Neutral action" onclick="{! c.toggleEdit }"/>
                    <lightning:button variant="brand" label="Save" title="Brand action" type="submit" />
            </lightning:recordEditForm>
            </aura:set>
        </aura:if>
    </aura:component>

<aura:component implements="forceCommunity:availableForAllPageTypes,force:hasRecordId" access="global" controller="CommunityComponentController">
    <aura:attribute name="recordId" type="String" />
    <aura:attribute name="edit" type="Boolean" default="true"/>
    <lightning:tabset>
        <lightning:tab>
            ... same code as above ...
        </lightning:tab>
    </lightning:tabset>
</aura:component>

<div class="slds-form-element__control">
    <lightning:outputField fieldName="Subject" variant="label-hidden" class="slds-form-element__static"/>
    <button class="slds-button slds-button_icon" title="Edit: Subject" onclick="{!c.toggleEdit}">
        <lightning:buttonIcon iconName="utility:edit" variant="bare"/>
            <span class="slds-assistive-text">Edit: Subject</span>
    </button>
</div>

<div class="slds-form-element__control">
    <lightning:outputField fieldName="Subject" variant="label-hidden" class="slds-form-element__static"/>
    <button class="slds-button slds-button_icon" title="Edit: Subject" onclick="{!c.toggleEdit}">
        <lightning:icon iconName="utility:edit" size="x-small" iconClass="slds-button slds-button_icon" />
            <span class="slds-assistive-text">Edit: Subject</span>
    </button>
</div>