一台裝置可以有多張SIM卡，最典型的例子就是眼下流行的“雙卡雙待”。每一張SIM卡都對應一個Subscription，找不到對應的中文術語，我們求助下翻譯軟體。
Subscription：谷歌翻譯為“訂閱”，依舊不明覺厲；繼續翻譯：
訂閱（Subscription）：定義了請求者與業務或業務操作之間的關聯關系。隻有定義了訂閱關系，才能通過業務政策，控制請求者對某個業務的通路行為。
我們用誰家的SIM卡就相當于訂閱(Subscription)誰家的業務，對應的SIM卡的資訊就是Subscription Information，比如營運商名稱、MNC、MCC等，多張SIM卡就有多個Subscription Information。
在Android中，針對上述功能的實作、管理就是SubscriptionManager，表現到軟體上就是：
各個類的實作比較簡單自行參看源碼。
SubscriptionManager作用有三個：
- 擷取Subscription資訊
- 更改Subscription某些資訊
- 提供OnSubscriptionsChangedListener監聽器，友善其他應用監聽Subscription的狀态改變
是時候看下Subscription了。
Subscription内容：
public class SubscriptionInfo implements Parcelable {
/**
* Subscription Identifier, this is a device unique number
* and not an index into an array
*/
private int mId;
/**
* The GID for a SIM that maybe associated with this subscription, empty if unknown
*/
private String mIccId;
/**
* The index of the slot that currently contains the subscription
* and not necessarily unique and maybe INVALID_SLOT_ID if unknown
*/
private int mSimSlotIndex;
/**
* The name displayed to the user that identifies this subscription
*/
private CharSequence mDisplayName;
/**
* String that identifies SPN/PLMN
* TODO : Add a new field that identifies only SPN for a sim
*/
private CharSequence mCarrierName;
/**
* The source of the name, NAME_SOURCE_UNDEFINED, NAME_SOURCE_DEFAULT_SOURCE,
* NAME_SOURCE_SIM_SOURCE or NAME_SOURCE_USER_INPUT.
*/
private int mNameSource;
/**
* A number presented to the user identify this subscription
*/
private String mNumber;
/**
* Data roaming state, DATA_RAOMING_ENABLE, DATA_RAOMING_DISABLE
*/
private int mDataRoaming;
/**
* Mobile Country Code
*/
private int mMcc;
/**
* Mobile Network Code
*/
private int mMnc;
/**
* ISO Country code for the subscription's provider
*/
private String mCountryIso;
}
一條Log：
SubscriptionController: [getSubInfoRecord] id:2 iccid:898600020XXXXXXXXXXX simSlotIndex:0 displayName:中國移動 carrierName:No service. nameSource:0 iconTint:-16746133 dataRoaming:0 mcc:460 mnc:2 countIso:cn
看下對應的術語：
ICCID：Integrate circuit card identity 內建電路卡識别碼（固化在手機SIM卡中）。ICCID為IC卡的唯一識别号碼，共有20位數字組成：
PLMN：Public Land Mobile Network 公共陸地移動網，一般某個國家的一個營運商對應一個PLMN
SPN：Service Provider Name 營運商名稱
MCC：Mobile Country Code，移動國家碼，MCC的資源由國際電聯（ITU）統一配置設定和管理，唯一識别移動使用者所屬的國家，共3位，中國為460
MNC：Mobile Network Code 移動網絡号碼，用于識别移動使用者所歸屬的移動通信網，2~3位數字組成，如中國移動系統使用00、02、04、07，中國聯通GSM系統使用01、06、09
ISO country code: 國際上不同國家的ISO編碼，比如我們國家：
那麼問題來了，這些資訊從哪來？
對于SubscriptionController來說，它是從資料庫telephony.db的siminfo表中讀取：
/data/data/com.android.providers.telephony/databases
siminfo表的建立：
TelephonyProvider.java (g:\rk3288-android6.0f\packages\providers\telephonyprovider\src\com\android\providers\telephony) 105530 2017-04-24
private void createSimInfoTable(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + SIMINFO_TABLE + "("
+ SubscriptionManager.UNIQUE_KEY_SUBSCRIPTION_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ SubscriptionManager.ICC_ID + " TEXT NOT NULL,"
+ SubscriptionManager.SIM_SLOT_INDEX + " INTEGER DEFAULT " + SubscriptionManager.SIM_NOT_INSERTED + ","
+ SubscriptionManager.DISPLAY_NAME + " TEXT,"
+ SubscriptionManager.CARRIER_NAME + " TEXT,"
+ SubscriptionManager.NAME_SOURCE + " INTEGER DEFAULT " + SubscriptionManager.NAME_SOURCE_DEFAULT_SOURCE + ","
+ SubscriptionManager.COLOR + " INTEGER DEFAULT " + SubscriptionManager.COLOR_DEFAULT + ","
+ SubscriptionManager.NUMBER + " TEXT,"
+ SubscriptionManager.DISPLAY_NUMBER_FORMAT + " INTEGER NOT NULL DEFAULT " + SubscriptionManager.DISPLAY_NUMBER_DEFAULT + ","
+ SubscriptionManager.DATA_ROAMING + " INTEGER DEFAULT " + SubscriptionManager.DATA_ROAMING_DEFAULT + ","
+ SubscriptionManager.MCC + " INTEGER DEFAULT 0,"
+ SubscriptionManager.MNC + " INTEGER DEFAULT 0,"
+ SubscriptionManager.CB_EXTREME_THREAT_ALERT + " INTEGER DEFAULT 1,"
+ SubscriptionManager.CB_SEVERE_THREAT_ALERT + " INTEGER DEFAULT 1,"
+ SubscriptionManager.CB_AMBER_ALERT + " INTEGER DEFAULT 1,"
+ SubscriptionManager.CB_EMERGENCY_ALERT + " INTEGER DEFAULT 1,"
+ SubscriptionManager.CB_ALERT_SOUND_DURATION + " INTEGER DEFAULT 4,"
+ SubscriptionManager.CB_ALERT_REMINDER_INTERVAL + " INTEGER DEFAULT 0,"
+ SubscriptionManager.CB_ALERT_VIBRATE + " INTEGER DEFAULT 1,"
+ SubscriptionManager.CB_ALERT_SPEECH + " INTEGER DEFAULT 1,"
+ SubscriptionManager.CB_ETWS_TEST_ALERT + " INTEGER DEFAULT 0,"
+ SubscriptionManager.CB_CHANNEL_50_ALERT + " INTEGER DEFAULT 1,"
+ SubscriptionManager.CB_CMAS_TEST_ALERT + " INTEGER DEFAULT 0,"
+ SubscriptionManager.CB_OPT_OUT_DIALOG + " INTEGER DEFAULT 1"
+ ");");
if (DBG) log("dbh.createSimInfoTable:-");
}
那麼又要問了，資料庫的資料從哪來？自然從SIM中讀取的了。
怎麼讀？通過AT指令讀！
怎麼通過AT指令讀？說過了。