Convert multi-line String to List in Flow Builder using Apex Invocable Method

Hello everyone, this post will show you how to convert multi-line String to List in Flow Builder using Apex Invocable Method.

In order to achieve this, we can create an Apex class and the test class as well.

// Apex Invocable class - StringToListUtil.apxc
public class StringToListUtil {
    
    @InvocableMethod(label='Convert String to List')
    public static List<List<String>> convertStringToList(List<String> inputParamStrings) { 
        
        List<List<String>> resultList = new List<List<String>>();
        
        for(String inputParamString : inputParamStrings){
            if(String.isBlank(inputParamString)) continue;
            
            List<String> innerResultList = new List<String>();
            for(String str : inputParamString.split('\r\n')){
                if(String.isBlank(str)) continue;
                innerResultList.add(str.trim());
            }
            resultList.add(new List<String>(innerResultList));
        }
 
        return resultList;
    }
}

// Apex test class - StringToListUtilTest.apxc
 
@isTest
public class StringToListUtilTest {
 
    @isTest
    public static void testConvertStringToListUtilMethod() {
        String str = '1\r\n2\r\n3';
        List<List<String>> res = StringToListUtil.convertStringToList(new List<String>{str});
        System.assertEquals(res.get(0), new list<String>{'1','2','3'});
    }
}

Next, let’s create a Screen Flow in Flow Builder. In order to demonstrate it in the simplest way, I have created this Flow with three components:

1. First Screen - Take the string input
2. Apex Action - Pass in the string input and assign the output to a collection variable
3. Next Screen - Output and see the result

In the first screen, we add a Long Text Area Component to the screen:

Next, we can add the Apex Action. We can pass the field into the input values and store the output values to your collection variable.

Once the string is converted to a list, we can output these variables to confirm the result:

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That’s it! Hope you learn something useful today! See ya!