Android：TelephonyManager.getSimSerialNumber（）返回null

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

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

TelehponyManager manager = (TelehponyManager)getSystemService(TELEPHONY_SERVICE);

String imei = manager.getDeviceId();

String imsi = manager.getSubscriberId();