TelephonyManager mr = Context.getSystemService(Context.TELEPHONY_SERVICE);
mr.listen(new MyPhoneStateListener(), PhoneStateListener.LISTEN_SIGNAL_STRENGTHS);
private class MyPhoneStateListener extends PhoneStateListener {
public void onSignalStrengthsChanged(SignalStrength signalStrength) {
super.onSignalStrengthsChanged(signalStrength);
public void listen (PhoneStateListener listener, int events) {
...
ITelephonyRegistry registry = getTelephonyRegistry();
if
(registry !=
null
) {
registry.listenForSubscriber(listener.mSubId, getOpPackageName(),
listener.callback, events, notifyNow);
}
else
{
Rlog.w(TAG,
"telephony registry not ready."
);
}
}
ITelephonyRegistry的实现类为
TelephonyRegistry.java
@TelephonyRegistry.java
@Override
public void listenForSubscriber(int subId, String pkgForDebug, IPhoneStateListener callback,
int events, boolean notifyNow) {
listen(pkgForDebug, callback, events, notifyNow, subId);
}
private void listen(String callingPackage, IPhoneStateListener callback, int events,
boolean notifyNow, int subId) {
...
int phoneId = SubscriptionManager.getPhoneId(subId);
synchronized (mRecords) {
// register
IBinder b = callback.asBinder();
Record r = add(b);
if (r == null) {
return;
}
r.context = mContext;
r.callback = callback;//这里将callback加到Record中
r.callingPackage = callingPackage;
r.callerUid = Binder.getCallingUid();
r.callerPid = Binder.getCallingPid();
...
}
看一下Record是什么？
@TelephonyRegistry.java
private Record add(IBinder binder) {
Record r;
synchronized (mRecords) {
final int N = mRecords.size();
for (int i = 0; i < N; i++) {
r = mRecords.get(i);
if (binder == r.binder) {
// Already existed.
return r;
}
}
r =
new
Record();
r.binder = binder;
r.deathRecipient = new TelephonyRegistryDeathRecipient(binder);
try {
binder.linkToDeath(r.deathRecipient, 0);
} catch (RemoteException e) {
if (VDBG) log("LinkToDeath remote exception sending to r=" + r + " e=" + e);
// Binder already died. Return null.
return null;
}
mRecords.add(r);
if (DBG) log("add new record");
}
return r;
}
由代码可知，每次注册一个监听事件，都new一个对应的Record，生成的Record又保存在一个ArrayList中，名为mRecords。
Record为TelephonyRegistry的内部类，这里保存一个PhoneStateListener对象
private
static
class Record {
Context context;
String callingPackage;
IBinder binder;
TelephonyRegistryDeathRecipient deathRecipient;
IPhoneStateListener callback;
...
}
标记一下这里，因为之前这些分析于我们这篇帖子的主题ServiceStateTracker好像一点关系没有，所有我们下面分析一下ServiceStateTracker。
ServiceStateTracker的初始化在上面已经介绍过了，这里不再赘述，其中ServiceStateTracker的构造方法中有一个重要的调用
@
ServiceStateTracker.java
public ServiceStateTracker(GsmCdmaPhone phone, CommandsInterface ci) {
...
updatePhoneType();
... }
public void updatePhoneType() {
...
mCi.getSignalStrength(obtainMessage(EVENT_GET_SIGNAL_STRENGTH));
... }
mCi是CommandsInterface的实例，CommandsInterface是一个接口类，这里的实现在RIL中。
@RIL.java
public class RIL extends BaseCommands implements CommandsInterface {
...
@Override
public void getSignalStrength(Message result) {
IRadio radioProxy = getRadioProxy(result);
if (radioProxy != null) {
RILRequest rr = obtainRequest(RIL_REQUEST_SIGNAL_STRENGTH, result,
mRILDefaultWorkSource);
if (RILJ_LOGD) riljLog(rr.serialString() + "> " + requestToString(rr.mRequest));
try {
radioProxy.getSignalStrength(rr.mSerial);
} catch (RemoteException | RuntimeException e) {
handleRadioProxyExceptionForRR(rr, "getSignalStrength", e);
}
}
}}
该方法是向modern获取信号，并向上返回结果，发送EVENT_GET_SIGNAL_STRENGTH消息。看一下解析
@ServiceStateTracker.java
@Override
public void handleMessage(Message msg) {
...
case EVENT_GET_SIGNAL_STRENGTH:
// This callback is called when signal strength is polled
// all by itself
if (!(mCi.getRadioState().isOn())) {
// Polling will continue when radio turns back on
return;
}
ar = (AsyncResult) msg.obj;
onSignalStrengthResult(ar);
queueNextSignalStrengthPoll();//重要！ 延时一段时间再次向RIL发送请求获取信号值，循环获取。androidP默认时间变更为20s
break;
... }
这里主要是onSignalStrengthResult(ar)方法。处理消息内容，发送给APP层。
protected boolean onSignalStrengthResult(AsyncResult ar) {
...
if ((ar.exception == null) && (ar.result != null)) {
mSignalStrength = (SignalStrength) ar.result;//接受消息返回的SignalStrength
mSignalStrength.validateInput();//验证信号值是否合规
if (dataRat == ServiceState.RIL_RADIO_TECHNOLOGY_UNKNOWN
&& voiceRat == ServiceState.RIL_RADIO_TECHNOLOGY_UNKNOWN) {
mSignalStrength.fixType();
} else {
mSignalStrength.setGsm(isGsm);
}
mSignalStrength.setLteRsrpBoost(mSS.getLteEarfcnRsrpBoost());
PersistableBundle config = getCarrierConfig();
mSignalStrength.setUseOnlyRsrpForLteLevel(config.getBoolean(
CarrierConfigManager.KEY_USE_ONLY_RSRP_FOR_LTE_SIGNAL_BAR_BOOL));
mSignalStrength.setLteRsrpThresholds(config.getIntArray(
CarrierConfigManager.KEY_LTE_RSRP_THRESHOLDS_INT_ARRAY));
mSignalStrength.setWcdmaDefaultSignalMeasurement(config.getString(
CarrierConfigManager.KEY_WCDMA_DEFAULT_SIGNAL_STRENGTH_MEASUREMENT_STRING));
mSignalStrength.setWcdmaRscpThresholds(config.getIntArray(
CarrierConfigManager.KEY_WCDMA_RSCP_THRESHOLDS_INT_ARRAY));
} else {
log("onSignalStrengthResult() Exception from RIL : " + ar.exception);
mSignalStrength = new SignalStrength(isGsm);
}
boolean ssChanged = notifySignalStrength();//发送phone通知SignalStrength状态改变
return ssChanged;
}
private SignalStrength mLastSignalStrength = null;
protected boolean notifySignalStrength() {
boolean notified = false;
if (!mSignalStrength.equals(mLastSignalStrength)) {
try {
mPhone.notifySignalStrength();
notified = true;
mLastSignalStrength = mSignalStrength;
} catch (NullPointerException ex) {
loge("updateSignalStrength() Phone already destroyed: " + ex
+ "SignalStrength not notified");
}
}
return notified;
}
@ Phone.java
public void notifySignalStrength() {
mNotifier.notifySignalStrength(this);
}
mNotifier为PhoneNotifier的实例，PhoneNotifier是一个接口类，这里具体实现类为DefaultPhoneNotifier.java
PS：mNotifier = new DefaultPhoneNotifier在PhoneFactory.makeDefaultPhone()中
@DefaultPhoneNotifier.java
@Override
public void notifySignalStrength(Phone sender) {
int phoneId = sender.getPhoneId();
int subId = sender.getSubId();
if (DBG) {
// too chatty to log constantly
Rlog.d(LOG_TAG, "notifySignalStrength: mRegistry=" + mRegistry
+ " ss=" + sender.getSignalStrength() + " sender=" + sender);
}
try {
if (mRegistry != null) {
mRegistry.notifySignalStrengthForPhoneId(phoneId, subId,
sender.getSignalStrength());
}
} catch (RemoteException ex) {
// system process is dead
}
}
mRegistry为ITelephonyRegistry的实例，感觉是不是哪里见过？看一下上面
mark一下的位置。
@
TelephonyRegistry.java
public
void
notifySignalStrengthForPhoneId
(
int
phoneId,
int
subId,
SignalStrength signalStrength) {
...
synchronized
(mRecords) {
if
(validatePhoneId(phoneId)) {
if
(VDBG) log(
"notifySignalStrengthForPhoneId: valid phoneId="
+ phoneId);
mSignalStrength[phoneId] = signalStrength;
for
(Record r : mRecords) {
if
(VDBG) {
log(
"notifySignalStrengthForPhoneId: r="
+ r +
" subId="
+ subId
+
" phoneId="
+ phoneId +
" ss="
+ signalStrength);
}
if
(r.matchPhoneStateListenerEvent(
PhoneStateListener.LISTEN_SIGNAL_STRENGTHS) &&
idMatch(r.subId, subId, phoneId)) {
try
{
r.callback.onSignalStrengthsChanged(
new
SignalStrength(signalStrength));
}
catch
(RemoteException ex) {
mRemoveList.add(r.binder);
}
}
...}
首先遍历mRecords集合，匹配PhoneStateListener.LISTEN_SIGNAL_STRENGTHS常量，调用r.callback.onSignalStrengthsChanged方法。
