在API 26中，getDeviceId()被贬低了，所以你可以使用下面的代码来满足API 26和更早的版本

TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
String imei="";
if (android.os.Build.VERSION.SDK_INT >= 26) {
  imei=telephonyManager.getImei();
}
else
{
  imei=telephonyManager.getDeviceId();
}

不要忘记为READ_PHONE_STATE添加使用上述代码的权限请求。

更新: 从Android 10开始，用户应用程序只能获得IMEI等不可重置的硬件标识符。

Kotlin代码获取DeviceId (IMEI)处理权限和可比性检查的所有android版本:

 val  telephonyManager = getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE)
        == PackageManager.PERMISSION_GRANTED) {
        // Permission is  granted
        val imei : String? = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)  telephonyManager.imei
        // older OS  versions
        else  telephonyManager.deviceId

        imei?.let {
            Log.i("Log", "DeviceId=$it" )
        }

    } else {  // Permission is not granted

    }

将此权限添加到AndroidManifest.xml:

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

我使用以下代码获取IMEI或使用Secure。ANDROID_ID作为替代，当设备没有电话功能时:

/**
 * Returns the unique identifier for the device
 *
 * @return unique identifier for the device
 */
public String getDeviceIMEI() {
    String deviceUniqueIdentifier = null;
    TelephonyManager tm = (TelephonyManager) this.getSystemService(Context.TELEPHONY_SERVICE);
    if (null != tm) {
        deviceUniqueIdentifier = tm.getDeviceId();
    }
    if (null == deviceUniqueIdentifier || 0 == deviceUniqueIdentifier.length()) {
        deviceUniqueIdentifier = Settings.Secure.getString(this.getContentResolver(), Settings.Secure.ANDROID_ID);
    }
    return deviceUniqueIdentifier;
}

你无法从andorid10 +或29+手机中获得imei号码，这里是用于为设备创建imei号码的替代功能。

public  static String getDeviceID(){
    String devIDShort = "35" + //we make this look like a valid IMEI
            Build.BOARD.length()%10+ Build.BRAND.length()%10 +
            Build.CPU_ABI.length()%10 + Build.DEVICE.length()%10 +
            Build.DISPLAY.length()%10 + Build.HOST.length()%10 +
            Build.ID.length()%10 + Build.MANUFACTURER.length()%10 +
            Build.MODEL.length()%10 + Build.PRODUCT.length()%10 +
            Build.TAGS.length()%10 + Build.TYPE.length()%10 +
            Build.USER.length()%10 ; //13 digits

    return  devIDShort;
}

你可以使用这个TelephonyManager TELEPHONY_SERVICE函数来获取唯一的设备ID， 要求权限:READ_PHONE_STATE

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

例如，GSM手机的IMEI, CDMA手机的MEID或ESN。

/**
 * Gets the device unique id called IMEI. Sometimes, this returns 00000000000000000 for the
 * rooted devices.
 **/
public static String getDeviceImei(Context ctx) {
    TelephonyManager telephonyManager = (TelephonyManager) ctx.getSystemService(Context.TELEPHONY_SERVICE);
    return telephonyManager.getDeviceId();
}

如果设备ID不可用，则返回null。

来自:http://mytechead.wordpress.com/2011/08/28/how-to-get-imei-number-of-android-device/:

下面的代码可以帮助获取android设备的IMEI号码:

TelephonyManager tm = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
String device_id = tm.getDeviceId();

Android Manifest中需要的权限:

android.permission.READ_PHONE_STATE

注意:如平板电脑或不能作为移动电话的设备 IMEI将为空。