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;
}

试试这个(总是需要第一个IMEI)

TelephonyManager mTelephony = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
        if (ActivityCompat.checkSelfPermission(LoginActivity.this,Manifest.permission.READ_PHONE_STATE)!= PackageManager.PERMISSION_GRANTED) {

         return;
}

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                if (mTelephony.getPhoneCount() == 2) {
                    IME = mTelephony.getImei(0);
                }else{
                    IME = mTelephony.getImei();
                }
            }else{
                if (mTelephony.getPhoneCount() == 2) {
                    IME = mTelephony.getDeviceId(0);
                } else {
                    IME = mTelephony.getDeviceId();
                }
            }
        } else {
            IME = mTelephony.getDeviceId();
        }

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-->

获取IMEI(国际移动设备标识符)

public String getIMEI(Activity activity) {
    TelephonyManager telephonyManager = (TelephonyManager) activity
            .getSystemService(Context.TELEPHONY_SERVICE);
    return telephonyManager.getDeviceId();
}

获取设备唯一id

public String getDeviceUniqueID(Activity activity){
    String device_unique_id = Secure.getString(activity.getContentResolver(),
            Secure.ANDROID_ID);
    return device_unique_id;
}

使用下面的代码给你IMEI号码:

TelephonyManager telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
System.out.println("IMEI::" + telephonyManager.getDeviceId());

对于Android 6.0+游戏已经改变，所以我建议你使用这个;

最好的方法是在运行时执行，否则会出现权限错误。

   /**
 * A loading screen after AppIntroActivity.
 */
public class LoadingActivity extends BaseActivity {
private static final int MY_PERMISSIONS_REQUEST_READ_PHONE_STATE = 0;
private TextView loading_tv2;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_loading);

    //trigger 'loadIMEI'
    loadIMEI();
    /** Fading Transition Effect */
    overridePendingTransition(android.R.anim.fade_in, android.R.anim.fade_out);
}

/**
 * Called when the 'loadIMEI' function is triggered.
 */
public void loadIMEI() {
    // Check if the READ_PHONE_STATE permission is already available.
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE)
            != PackageManager.PERMISSION_GRANTED) {
        // READ_PHONE_STATE permission has not been granted.
        requestReadPhoneStatePermission();
    } else {
        // READ_PHONE_STATE permission is already been granted.
        doPermissionGrantedStuffs();
    }
}



/**
 * Requests the READ_PHONE_STATE permission.
 * If the permission has been denied previously, a dialog will prompt the user to grant the
 * permission, otherwise it is requested directly.
 */
private void requestReadPhoneStatePermission() {
    if (ActivityCompat.shouldShowRequestPermissionRationale(this,
            Manifest.permission.READ_PHONE_STATE)) {
        // Provide an additional rationale to the user if the permission was not granted
        // and the user would benefit from additional context for the use of the permission.
        // For example if the user has previously denied the permission.
        new AlertDialog.Builder(LoadingActivity.this)
                .setTitle("Permission Request")
                .setMessage(getString(R.string.permission_read_phone_state_rationale))
                .setCancelable(false)
                .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        //re-request
                        ActivityCompat.requestPermissions(LoadingActivity.this,
                                new String[]{Manifest.permission.READ_PHONE_STATE},
                                MY_PERMISSIONS_REQUEST_READ_PHONE_STATE);
                    }
                })
                .setIcon(R.drawable.onlinlinew_warning_sign)
                .show();
    } else {
        // READ_PHONE_STATE permission has not been granted yet. Request it directly.
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_PHONE_STATE},
                MY_PERMISSIONS_REQUEST_READ_PHONE_STATE);
    }
}

/**
 * Callback received when a permissions request has been completed.
 */
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                       @NonNull int[] grantResults) {

    if (requestCode == MY_PERMISSIONS_REQUEST_READ_PHONE_STATE) {
        // Received permission result for READ_PHONE_STATE permission.est.");
        // Check if the only required permission has been granted
        if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            // READ_PHONE_STATE permission has been granted, proceed with displaying IMEI Number
            //alertAlert(getString(R.string.permision_available_read_phone_state));
            doPermissionGrantedStuffs();
        } else {
            alertAlert(getString(R.string.permissions_not_granted_read_phone_state));
          }
    }
}

private void alertAlert(String msg) {
    new AlertDialog.Builder(LoadingActivity.this)
            .setTitle("Permission Request")
            .setMessage(msg)
            .setCancelable(false)
            .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    // do somthing here
                }
            })
            .setIcon(R.drawable.onlinlinew_warning_sign)
            .show();
}


public void doPermissionGrantedStuffs() {
    //Have an  object of TelephonyManager
    TelephonyManager tm =(TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
    //Get IMEI Number of Phone  //////////////// for this example i only need the IMEI
    String IMEINumber=tm.getDeviceId();

    /************************************************
     * **********************************************
     * This is just an icing on the cake
     * the following are other children of TELEPHONY_SERVICE
     *
     //Get Subscriber ID
     String subscriberID=tm.getDeviceId();

     //Get SIM Serial Number
     String SIMSerialNumber=tm.getSimSerialNumber();

     //Get Network Country ISO Code
     String networkCountryISO=tm.getNetworkCountryIso();

     //Get SIM Country ISO Code
     String SIMCountryISO=tm.getSimCountryIso();

     //Get the device software version
     String softwareVersion=tm.getDeviceSoftwareVersion()

     //Get the Voice mail number
     String voiceMailNumber=tm.getVoiceMailNumber();


     //Get the Phone Type CDMA/GSM/NONE
     int phoneType=tm.getPhoneType();

     switch (phoneType)
     {
     case (TelephonyManager.PHONE_TYPE_CDMA):
     // your code
     break;
     case (TelephonyManager.PHONE_TYPE_GSM)
     // your code
     break;
     case (TelephonyManager.PHONE_TYPE_NONE):
     // your code
     break;
     }

     //Find whether the Phone is in Roaming, returns true if in roaming
     boolean isRoaming=tm.isNetworkRoaming();
     if(isRoaming)
     phoneDetails+="\nIs In Roaming : "+"YES";
     else
     phoneDetails+="\nIs In Roaming : "+"NO";


     //Get the SIM state
     int SIMState=tm.getSimState();
     switch(SIMState)
     {
     case TelephonyManager.SIM_STATE_ABSENT :
     // your code
     break;
     case TelephonyManager.SIM_STATE_NETWORK_LOCKED :
     // your code
     break;
     case TelephonyManager.SIM_STATE_PIN_REQUIRED :
     // your code
     break;
     case TelephonyManager.SIM_STATE_PUK_REQUIRED :
     // your code
     break;
     case TelephonyManager.SIM_STATE_READY :
     // your code
     break;
     case TelephonyManager.SIM_STATE_UNKNOWN :
     // your code
     break;

     }
     */
    // Now read the desired content to a textview.
    loading_tv2 = (TextView) findViewById(R.id.loading_tv2);
    loading_tv2.setText(IMEINumber);
}
}

希望这能帮助到你或其他人。