For most fields on a layout, there is only one component per layout item. However, in a display-only view, the QuickAction.DescribeLayoutItem might be a composite of the individual fields (for example, an address can consist of street, city, state, country, and postal code data). On the corresponding edit view, each component of the address field would be split up into separate QuickAction.DescribeLayoutItems.
The following are methods for DescribeLayoutItem. All are instance methods.
public List<QuickAction.DescribeLayoutComponent> getLayoutComponents()
public Boolean isEditableForNew()
Type: Boolean
public Boolean isEditableForUpdate()
Type: Boolean
public Boolean isPlaceholder()
Type: Boolean
public Boolean isRequired()
Type: Boolean
This is useful if, for example, you want to render required fields in a contrasting color.