Custom picker for dummies

Question

I've been trying to figure out step by step how to create my own address picker. 
 Most of the questions I've run into here are too specific and don't cover basics. Also, I didn't find an example or tutorial in the online Appian course for this topic. 
 So, please help! 
 
 This is my case: 
 Simple address table example (table has some more columns but I believe they are irrelevant for this story): 
 ID : 1 ADDRESS_TEXT_ID: "3RD AVENUE-15-NEW YORK-55555" 
 ID : 2 ADDRESS_TEXT_ID: "5TH AVENUE-10A-LOS ANGELES-12345" 
 ID : 3 ADDRESS_TEXT_ID: "UPPER STREET-14-AUSTIN-52154" 
 
 What I need is a picker that starts searching my address database table with rows like those above after I type at least 3 characters. It allows only 1 selection that needs to be represented with address text (label) and stored as its numerical ID in rule input (rule input is CDT, so the input field should be ri!employee.addressId ). 
 This is the rule I've created for search: 
 
 a!queryEntity(
 entity: cons!EEDM_ADDRESS_DATA_STORE_ENTITY,
 query: a!query(
 logicalExpression: a!queryLogicalExpression(
 operator: "AND",
 filters: {
 a!queryFilter(
 field: "addressTextId",
 operator: "includes",
 value: upper(ri!searchText)
 )
 },
 ignoreFiltersWithEmptyValues: true
 ),
 pagingInfo: a!pagingInfo(
 startIndex: 1,
 batchSize: 50
 )
 ),
 fetchTotalCount: false
).data 
 
 This is my custom picker code now: 
 a!pickerFieldCustom(
 label: "Pick address",
 labelPosition: "ABOVE",
 instructions: "",
 helptooltip: "Start typing address text ID and address containing input string will be shown",
 placeholder: "---Type address text ID ---",
 maxselections: 1,
 suggestfunction: rule!EEDM_SearchAddressByString(_),
 value: ri!employee.addressId,
 saveInto: ri!employee.addressId,
 validations: {}
) 
 
 I know I'm missing some key properties but I don't get how to define them. 
 
 Could anyone give me step by step example how to finish this picker?

Stewart Burchell · Accepted Answer

Hi Ivan 
 You'll need to break this down a little bit more. The Custom Picker field needs to have a couple of rules to support it: 
 
 one to perform the actual search - so you start typing in your search text and the suggest function returns the candidates, and when you select one of them it stores the relevant identifier in the ri!employee.addressId. I think you've got that pretty well covered 
 the a!pickerFieldCustom() also needs to display a label for the item you've picked. This label will be held in the 'selectedLabels' attribute. So you'll need another rule to fetch the data based upon the addressId that you've stored in order to return the relevant label 
 in terms of only triggering the search when you've keyed in > 3 characters you can do that in the your suggestFunction by returning any empty datasubset until the user has keyed in > 2 characters

vinayr273 · Answer

Hi, 
 please find the updated code 
 with(
 
 local!matches: where(
 a!forEach(
 items: ri!labels, 
 expression: search( ri!filter, fv!item)
 )
 ),
 
 if(
 len(ri!filter) >= 3,
 a!dataSubset(
 data: index( ri!labels, local!matches), 
 identifiers: index( ri!identifiers, local!matches)
 ),
 todatasubset({})
 )
 
)



a!pickerFieldCustom(
 label: "Pick address",
 labelPosition: "ABOVE",
 instructions: "",
 helptooltip: "Start typing address text ID and address containing input string will be shown",
 placeholder: "---Type address text ID ---",
 maxselections: 1,
 suggestFunction: rule!EEDM_ArrayPickerFilter(
 filter:_ , 
 labels: index(local!allAddress,"ADDRESS_TEXT_ID",null), 
 identifiers: index(local!allAddress,"ID",null)
 ),
 selectedLabels: a!forEach(
 items: ri!employee.addressId,
 expression: index(index(local!allAddress,"ADDRESS_TEXT_ID",null), wherecontains(tointeger(fv!item), tointeger(index(local!allAddress,"ID",null))))
 ),
 
 value: ri!employee.addressId,
 saveInto: ri!employee.addressId,
 validations: {}
)

Stewart Burchell · Answer

My approach here would be to allow the search be run directly against the database and to be narrowed down to something that would reduce the result set as quickly as possible e.g. a post-code. So your picker could still display the entire address but the search is just using the input postcode to return what should be a very small subset of the overall data.If you ensure that the address is stored in its component parts then postcode would be in its own column, and could have a clustered index on it so that all of the adjacent addresses are retrieved in as few psychical fetches from the disk as possible.

Custom picker for dummies

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