using if statements in interface

Multiple conditions in Appian can be configured using or() & and() functions. 

a!richTextDisplayField(
  value: {
    a!richTextItem(
      if(
        ri!WorkingHours = "8",
        "Working hours are complete",
        if(
          and(8 > ri!WorkingHours, ri!WorkingHours > 0),
          "Working hours are not complete",
          if(
            ri!WorkingHours < 0,
            "insert working hours correctly please",
            {}
          )
        )
      )
    )
  }
)

Using the amazing match function.

a!richTextDisplayField(
  value: {
    a!richTextItem(
      a!match(
        value: ri!WorkingHours,
        equals: 8,
        then: "Working Hours are complete",
        whenTrue: and(ri!WorkingHours > 0, 8 > ri!WorkingHours),
        then: "Working hours are not complete",
        default: "insert working hours correctly please"
      )
    )
  }
)

Thanks for your help, but when I tried the code I got this: Could not display interface. Please check definition and inputs. Interface Definition: Expression evaluation error at function 'if' [line 64]: Invalid number of parameters, function 'if' a minimum of 3 parameters (condition,true,false), passed 2.

try this

a!richTextDisplayField(
  value: {
    a!richTextItem(
      if(
        ri!WorkingHours = "8",
        "Working hours are complete",
        if(
          and(8 > ri!WorkingHours, ri!WorkingHours > 0),
          "Working hours are not complete",
          "insert working hours correctly please"
    
        )
      )
    )
  }
)

Ali Abdulqawi

I missed the third parameter in the last if. You can add an empty list there. I have updated the same code

its because the third if only have two parameters in it 

if(
            ri!WorkingHours < 0,
            "insert working hours correctly please"
            )

if(
            ri!WorkingHours < 0,
            "insert working hours correctly please",
            "working hours passed limit"
          )

Thanks, it's working now, but I'm wondering should I use three conditions every time I want use if statement?

can't I use two only? 

it just show the default message even when the user inserts 8, or 4

Did you take a look at Ujjwal's answer? I think it is a better approach. 

workings hours as 8 

working hours as 4