Using mergLA - iOS Touch ID

mergLA is an iOS external that adds a command to present a local authentication dialog to the user if they have setup biometric authentication.

Present the authentication dialog

To present the authentication dialog use the mergLAEvaluate command.

command authenticateUser
      mergLAEvaluate "Place your finger on the Home button to log in to MyApp"
      if the result is "success"  then
         answer "Error:" & the result
      end if
end authenticateUser

An authentication dialog will be presented to the user.

Handle the result

The result will be one of

  • success
  • user cancelled
  • system cancelled
  • fallback
  • failed
  • can not evaluate
  • not available on this system version

You can take action depending on the result of mergLAEvaluate.

Testing on the iOS Simulator

Enroll Touch ID

You can test Touch ID on the simulator.

First ensure Touch ID is enrolled by Choosing Hardware -> Touch ID -> Enrolled.

Run Touch ID in your app

Now run Touch ID in your app and when you are presented with the dialog choose either

Hardware -> Touch ID -> Matching Touch (to simulate a recognised touch)


Hardware -> Touch ID -> Non-matching Touch (to simulate a non-recognised touch)


If a Matching Touch is simulated mergLAEvaluate will return "success".

If a Non-matching Touch is simulated mergLAEvaluate will show a Try Again dialog allowing the user to Try Again, Enter Password or Cancel.

Touch ID is not enrolled

If Touch ID is not enrolled mergLAEvaluate will return "can not evaluate".

If Touch ID is not available on the device being simulated mergLAEvaluate will return "not available on this system version".


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