Phone Number Hint

The Phone Number Hint API, a library powered by Google Play services, provides a frictionless way to show a user's (SIM-based) phone numbers as a hint.

The benefits to using Phone Number Hint include the following:

  • No additional permission requests are needed
  • Eliminates the need for the user to manually type in the phone number
  • No Google Account is needed
  • Not directly tied to sign-in or sign-up workflows
  • Wider support for Android versions compared to Autofill

How it works

The Phone Number Hint API utilizes a PendingIntent to initiate the flow. Once the PendingIntent has been launched the user will be presented with a UI, listing out all (SIM-based) phone numbers. The user can then choose to select a phone number they would like to use or cancel the flow. The selected phone number will then be made available to the developer to retrieve from the Intent.

Phone Number Hint UI and Settings.
Figure 1. Phone Number Hint UI and Settings

To prepare your app, complete the steps in the following sections.

Configure your app

Add the Google Play services dependency for the Phone Number Hint API to your module's Gradle build file, which is commonly app/build.gradle:

  apply plugin: 'com.android.application'

  ...

  dependencies {
    implementation 'com.google.android.gms:play-services-auth:21.4.0'
  }

Create a GetPhoneNumbeHintIntentRequest object

Start by creating a GetPhoneNumberHintIntentRequest object using the provided GetPhoneNumberHintIntentRequest.Builder() method. This request object can then be used to get an Intent to start the Phone Number Hint flow.

Kotlin

val request: GetPhoneNumberHintIntentRequest = GetPhoneNumberHintIntentRequest.builder().build()

Java

GetPhoneNumberHintIntentRequest request = GetPhoneNumberHintIntentRequest.builder().build();

Requesting Phone Number Hint

Call SignInClient.getPhoneNumberHintIntent(), passing in the previous GetPhoneNumberHintIntentRequest object, to retrieve the PendingIntent to initiate the Phone Number Hint flow.

Kotlin

val phoneNumberHintIntentResultLauncher = ...

Identity.getSignInClient(activity)
.getPhoneNumberHintIntent(request)
.addOnSuccessListener { result: PendingIntent ->
  try {
    phoneNumberHintIntentResultLauncher.launch(
      IntentSenderRequest.Builder(result).build()
    )
  } catch (e: Exception) {
      Log.e(TAG, "Launching the PendingIntent failed")
  }
}
.addOnFailureListener {
    Log.e(TAG, "Phone Number Hint failed")
}

Java

ActivityResultLauncher phoneNumberHintIntentResultLauncher = ...

Identity.getSignInClient(activity)
  .getPhoneNumberHintIntent(request)
  .addOnSuccessListener( result -> {
      try {
          phoneNumberHintIntentResultLauncher.launch(result.getIntentSender());
      } catch(Exception e) {
          Log.e(TAG, "Launching the PendingIntent failed", e);
      }
  })
  .addOnFailureListener(e -> {
      Log.e(TAG, "Phone Number Hint failed", e);
  });

Retrieving the phone number

Pass in the Intent to SignInClient.getPhoneNumberFromIntent to retrieve the phone number.

Kotlin

val phoneNumberHintIntentResultLauncher =
registerForActivityResult(ActivityResultContracts.StartIntentSenderForResult()) { result ->
      try {
          val phoneNumber = Identity.getSignInClient(activity).getPhoneNumberFromIntent(result.data)
      } catch(e: Exception) {
          Log.e(TAG, "Phone Number Hint failed")
      }
  }

Java

ActivityResultLauncher phoneNumberHintIntentResultLauncher =
  registerForActivityResult(
      new ActivityResultContracts.StartActivityForResult(),
      new ActivityResultCallback() {
          @Override
          public void onActivityResult(ActivityResult result) {
              try {
                  String phoneNumber = Identity.getSignInClient(activity).getPhoneNumberFromIntent(result.getData());
              } catch {
                  Log.e(TAG, "Phone Number Hint failed", e);
              }
          }
  });