Add specific validation to text

You can use regex functions to match with specific text pattern and use its result for displaying validation on the text field. 

{
  a!textField(
    label: "Release Version",
    labelPosition: "ABOVE",
    value: ri!value,
    saveInto: {
      ri!value      
    },
    refreshAfter: "UNFOCUS",
    validations: {
      if(
        regexmatch(
          "^(\d+\.)(\d+\.)(\*|\d+)$",
          ri!value
        ),
        {},
        "Enter correct format XX.XX.XX"
      )
    }    
  )
}

Use this web based tool to explain / understand the regex pattern - https://regexr.com/

can you please help me with how can we apply validations on the decimal field

In the decimal field accept values up to 2 decimal places only.

I tried with fixed function but it's not working

fixed(ri!record.amout,2)

For validation, you can use the below code.

a!localVariables(
  local!dec,
  a!floatingPointField(
    label: "Decimal Number",
    value: local!dec,
    saveInto: local!dec,
    validations: if(
      a!isNullOrEmpty(local!dec),
      {},
      if(
        regexmatch(
          "^\-?[0-9]+(?:\.[0-9]{1,2})?$",
          todecimal(local!dec)
        ),
        {},
        "Error"
      )
    )
  )
)

For validation, you can use the below code.

a!localVariables(
  local!dec,
  a!floatingPointField(
    label: "Decimal Number",
    value: local!dec,
    saveInto: local!dec,
    validations: if(
      a!isNullOrEmpty(local!dec),
      {},
      if(
        regexmatch(
          "^\-?[0-9]+(?:\.[0-9]{1,2})?$",
          todecimal(local!dec)
        ),
        {},
        "Error"
      )
    )
  )
)