我注意到有几个回复都发了同样的东西。首先，从2021年开始，onActivityResult已弃用。下面是不弃用的解决方案。

private fun requestHint() {

    val hintRequest = HintRequest.Builder()
        .setPhoneNumberIdentifierSupported(true)
        .build()

    val intent = Credentials.getClient(this).getHintPickerIntent(hintRequest)
    val intentSender = IntentSenderRequest.Builder(intent.intentSender).build()

    val resultLauncher = registerForActivityResult(
        ActivityResultContracts.StartIntentSenderForResult()
    ) { result ->
        if (result.resultCode == Activity.RESULT_OK) {
            val credential: Credential? = result.data?.getParcelableExtra(Credential.EXTRA_KEY)
            // Phone number with country code
            Log.i("mTag", "Selected phone No: ${credential?.id}")
        }
    }
    resultLauncher.launch(intentSender)
}

注意:虽然很多人认为这可以让你检索用户的手机号码。通常情况并非如此。谷歌播放服务缓存了几个电话号码，有时对话框显示电话号码，其中不属于用户。

一个重要的导入。com.google.android.gms.auth.api.credentials.Credential

参考文档提供了详细信息，但代码有些不推荐。

我注意到有几个回复都发了同样的东西。首先，从2021年开始，onActivityResult已弃用。下面是不弃用的解决方案。

private fun requestHint() {

    val hintRequest = HintRequest.Builder()
        .setPhoneNumberIdentifierSupported(true)
        .build()

    val intent = Credentials.getClient(this).getHintPickerIntent(hintRequest)
    val intentSender = IntentSenderRequest.Builder(intent.intentSender).build()

    val resultLauncher = registerForActivityResult(
        ActivityResultContracts.StartIntentSenderForResult()
    ) { result ->
        if (result.resultCode == Activity.RESULT_OK) {
            val credential: Credential? = result.data?.getParcelableExtra(Credential.EXTRA_KEY)
            // Phone number with country code
            Log.i("mTag", "Selected phone No: ${credential?.id}")
        }
    }
    resultLauncher.launch(intentSender)
}

注意:虽然很多人认为这可以让你检索用户的手机号码。通常情况并非如此。谷歌播放服务缓存了几个电话号码，有时对话框显示电话号码，其中不属于用户。

一个重要的导入。com.google.android.gms.auth.api.credentials.Credential

参考文档提供了详细信息，但代码有些不推荐。

对于android版本>= LOLLIPOP_MR1:

增加权限:

叫它:

 val subscriptionManager =
        getSystemService(Context.TELEPHONY_SUBSCRIPTION_SERVICE) as SubscriptionManager
    
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE) == PackageManager.PERMISSION_GRANTED) {
        
val list = subscriptionManager.activeSubscriptionInfoList
        for (info in list) {
            Log.d(TAG, "number " + info.number)
            Log.d(TAG, "network name : " + info.carrierName)
            Log.d(TAG, "country iso " + info.countryIso)
        }
    }

更新:这个答案不再可用，因为Whatsapp已经停止将电话号码作为帐户名，请忽略这个答案。

实际上，如果你不能通过电话服务获得它，你可以考虑另一种解决方案。

到今天为止，你可以依靠另一个大型应用程序Whatsapp，使用AccountManager。数以百万计的设备安装了这个应用程序，如果你不能通过TelephonyManager获得电话号码，你可以试试这个。

许可:

<uses-permission android:name="android.permission.GET_ACCOUNTS" />

代码:

AccountManager am = AccountManager.get(this);
Account[] accounts = am.getAccounts();

for (Account ac : accounts) {
    String acname = ac.name;
    String actype = ac.type;
    // Take your time to look at all available accounts
    System.out.println("Accounts : " + acname + ", " + actype);
}

检查WhatsApp帐户的actype

if(actype.equals("com.whatsapp")){
    String phoneNumber = ac.name;
}

当然，如果用户没有安装WhatsApp，你可能不会得到它，但无论如何都值得一试。 记住，你应该总是询问用户的确认。

TelephonyManager不是正确的解决方案，因为在某些情况下，号码没有存储在SIM卡中。我建议您在应用程序第一次打开时使用共享首选项存储用户的电话号码，并且在需要时使用该号码。

以下是我找到的解决方案的组合(这里是示例项目，如果你也想检查自动填充):

清单

    <uses-permission android:name="android.permission.READ_PHONE_STATE" />

build.gradle

    implementation "com.google.android.gms:play-services-auth:17.0.0"

MainActivity.kt

class MainActivity : AppCompatActivity() {
    private lateinit var googleApiClient: GoogleApiClient

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        tryGetCurrentUserPhoneNumber(this)
        googleApiClient = GoogleApiClient.Builder(this).addApi(Auth.CREDENTIALS_API).build()
        if (phoneNumber.isEmpty()) {
            val hintRequest = HintRequest.Builder().setPhoneNumberIdentifierSupported(true).build()
            val intent = Auth.CredentialsApi.getHintPickerIntent(googleApiClient, hintRequest)
            try {
                startIntentSenderForResult(intent.intentSender, REQUEST_PHONE_NUMBER, null, 0, 0, 0);
            } catch (e: IntentSender.SendIntentException) {
                Toast.makeText(this, "failed to show phone picker", Toast.LENGTH_SHORT).show()
            }
        } else
            onGotPhoneNumberToSendTo()

    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        if (requestCode == REQUEST_PHONE_NUMBER) {
            if (resultCode == Activity.RESULT_OK) {
                val cred: Credential? = data?.getParcelableExtra(Credential.EXTRA_KEY)
                phoneNumber = cred?.id ?: ""
                if (phoneNumber.isEmpty())
                    Toast.makeText(this, "failed to get phone number", Toast.LENGTH_SHORT).show()
                else
                    onGotPhoneNumberToSendTo()
            }
        }
    }

    private fun onGotPhoneNumberToSendTo() {
        Toast.makeText(this, "got number:$phoneNumber", Toast.LENGTH_SHORT).show()
    }


    companion object {
        private const val REQUEST_PHONE_NUMBER = 1
        private var phoneNumber = ""

        @SuppressLint("MissingPermission", "HardwareIds")
        private fun tryGetCurrentUserPhoneNumber(context: Context): String {
            if (phoneNumber.isNotEmpty())
                return phoneNumber
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                val subscriptionManager = context.getSystemService(Context.TELEPHONY_SUBSCRIPTION_SERVICE) as SubscriptionManager
                try {
                    subscriptionManager.activeSubscriptionInfoList?.forEach {
                        val number: String? = it.number
                        if (!number.isNullOrBlank()) {
                            phoneNumber = number
                            return number
                        }
                    }
                } catch (ignored: Exception) {
                }
            }
            try {
                val telephonyManager = context.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager
                val number = telephonyManager.line1Number ?: ""
                if (!number.isBlank()) {
                    phoneNumber = number
                    return number
                }
            } catch (e: Exception) {
            }
            return ""
        }
    }
}