Data flow analysis of phone calls in Android
- 2020-05-07 20:27:56
- OfStack
1. The starting point of all process starts, press the dial key after dialing code in this step in/android sourcecode/packages/Contacts/src/com/android/contacts/directory TwelveKeyDialer. java file, the code is as follows:
The newDialNumberIntent() method in code is defined as :
It can be seen from the definition of newDialNumberIntent that when the dial key is pressed, TwelveKeyDial will launch a specific component. The ACTION of this component is ACTION_CALL_PRIVILEGED. After searching, the component launched by ACTION is a file of the following: /android sourcecode/packeges/Phone/. PrivilegedOutgoingCallBroadcast, but we to/android sourcecode/packeges/Phone src /... The file cannot be found because it is marked AndroidMenifest.xml with something special :
< activity-alias / > , this tag means that this Activity is the alias of another Activity. The real Activity is marked with "android:targetActivity = OutgoingCallBroadcast" in the tag, so the real "identity" of PrivilegedOutgoingCallBroadcast initiated by "ACTION_CALL_PRIVILEGED" is "OutgoingCallBroadcast".
2. At this time, the data of the phone has been transferred to OutgoingCallBroadcast.java.
In the onCreate() method of OutgoingCallBroadcast.java:
dialButtonPressed() {
.........
final String number = mDigits.getText().toString();
startActivity(newDialNumberIntent(number));
mDigits.getText().clear();
finish();
}
The newDialNumberIntent() method in code is defined as :
private Intent newDialNumberIntent(String number) {
final Intent intent = new Intent(Intent.ACTION_CALL_PRIVILEGED, Uri.fromParts("tel", number, null));
.............
}
It can be seen from the definition of newDialNumberIntent that when the dial key is pressed, TwelveKeyDial will launch a specific component. The ACTION of this component is ACTION_CALL_PRIVILEGED. After searching, the component launched by ACTION is a file of the following: /android sourcecode/packeges/Phone/. PrivilegedOutgoingCallBroadcast, but we to/android sourcecode/packeges/Phone src /... The file cannot be found because it is marked AndroidMenifest.xml with something special :
< activity-alias / > , this tag means that this Activity is the alias of another Activity. The real Activity is marked with "android:targetActivity = OutgoingCallBroadcast" in the tag, so the real "identity" of PrivilegedOutgoingCallBroadcast initiated by "ACTION_CALL_PRIVILEGED" is "OutgoingCallBroadcast".
2. At this time, the data of the phone has been transferred to OutgoingCallBroadcast.java.
In the onCreate() method of OutgoingCallBroadcast.java:
<PRE class=java name="code">protected void onCreate(Bundle icicle) {
.......
Intent intent = getIntent();
........
String action = intent.getAction();
.......
final boolean emergencyNum = (number != null) && PhoneNumUtils.isEmergencyNumber(number);// Determine if the number is an emergency number
.......
if (Intent.ACTION_CALL_PRIVILEGED.equals(action)) {
action = emergencyNum ? Intent.ACTION_CALL_EMERGENCY : Intent.ACTION_CALL;
intent.setAction(action);
}
.......
intent.setClass(this, InCallScreen.class);
startActivity(intent);
}</PRE><P></P>
<PRE></PRE>
In this method, determine if received ACTION Is" ACTION_CALL_PRIVILEGED ", then convert according to whether the number entered is an emergency number. If it is an emergency number, then ACTION = Intent.ACTION_CALL_EMERGENCY, Otherwise, ACTION = Intent.ACTION_CALL, And start the transformation Activity : InCallScreen.java
<P></P>
<P>3. InCallScreen.java Still in the catalog /packeges/Phone/src/com/android/phone Under. </P>
<P>InCallScreen the onCreate In the call initInCallScreen Initialize the call interface and call registerForPhoneStates Register phone status monitor .<BR>
</P>
<P> in onNewIntent() Among the methods: </P>
<P><PRE class=java name="code">protected void onNewIntent(Intent intent) {
..........
String action = intent.getAction();
..........
else if (action.equals(Intent.ACTION_CALL) || action.equals(Intent.ACTION_CALL_EMERGENCY)) {
..........
InCallInitStatus status = placeCall(intent);
}
}
//placeCall
private InCallInitStatus placeCall(Intent intent) {
..............
int callStatus = PhoneUtils.placeCall(........);
}</PRE>InCallScreen.java In the placeCall The method call PhoneUtils.java Of the file placeCall Methods. <BR>
<P></P>
<P>4. PhoneUtils.java Still in the catalog /packeges/Phone/src/com/android/phone Under. </P>
<P><PRE class=java name="code">public static int placeCall(...) {
Connection connection;
connection = PhoneApp.getInstance().mCM.dial(phone, numberToDial);
}</PRE> Keep tracking, in PhoneApp.java Found in, mCM is CallManager.java Of the class 1 Objects, and CallManager.java It is to belong to frameworks Layer, so at this point the data stream has entered frameworks.<P></P>
<P>5. Enter the /frameworks/base/telephony/java/com/android/internal/telephony Directory. </P>
<P> in CallManager.java the dial() In the method, there are: </P>
<P><PRE class=java name="code"><SPAN style="BACKGROUND-COLOR: rgb(255,255,255); FONT-FAMILY: Arial, Verdana, sans-serif; WHITE-SPACE: normal"></SPAN><PRE class=java name="code">public Connection dial(Phone phone, String dialNumber) throws CallStateException {
Phone basePhone = getPhoneBase(phone);
Connection result;
<SPAN style="COLOR: #3333ff">result = basePhone.dial(dialString);</SPAN>
........
}
private static Phone getPhoneBase(Phone phone) {
if (phone instanceof PhoneProxy) {
<SPAN style="COLOR: #ff0000">return phone.getForegroundCall().getPhone();</SPAN>
}
return phone;
}</PRE><P></P>
<PRE></PRE>
<PRE class=java name="code"><SPAN style="BACKGROUND-COLOR: rgb(255,255,255); FONT-FAMILY: Arial, Verdana, sans-serif; WHITE-SPACE: normal"> Follow up and find: </SPAN></PRE><PRE class=java name="code"><SPAN style="BACKGROUND-COLOR: rgb(255,255,255); FONT-FAMILY: Arial, Verdana, sans-serif; WHITE-SPACE: normal">PhoneBase.java The abstract class implements the interface Phone.java, while GSMPhone.java It also implements abstract classes PhoneBase, so :</SPAN></PRE>
<P></P>
<P> In the above code: phone.getForegroundCall() Actual equivalent GSMPhone The object executes getForegroundCall() Methods. </P>
<P>6. Continue to track GSMPhone.java, This class is located in the /frameworks/base/telephony/java/com/android/internal/telephony/gsm/ Under. </P>
<P><PRE class=java name="code">GSMPhone.java :
GsmCallTracker mCT;
public GsmCall getForegroundCall() {
return mCT.foregroundCall;
}</PRE> It can be seen that getForegroundCall() Function continues to call GsmCallTracker.java the foregroundCall Properties. <P></P>
<P>7.GsmCallTracker.java Located in the /frameworks/base/telephony/java/com/android/internal/telephony/gsm/ Under the .</P>
<P><PRE class=cpp name="code">GsmCallTracker.java:
GSMCall foregroundCall = new GSMCall(this);</PRE><P></P>
<P> Open the GSMCall.java, find getPhone() Methods: </P>
<P><PRE class=java name="code">GSMCallTracker owner;
public Phone getPhone() {
return owner.phone;
}</PRE><P></P>
<P> And in the GSMCallTracker.java Has the following statement: </P>
<P><PRE class=cpp name="code">GSMPhone phone;</PRE><P></P>
<P><SPAN style="COLOR: #ff0000"> So here we are 1 Conclusion: no. 5 Part of the code marked red is what is returned GSMPhone The object, </SPAN><SPAN style="COLOR: #3333ff"> Into the 1 The step is going to be number one 5 Part of the code marked in blue is called GSMPhone The object's dial Methods. </SPAN></P>
<P>8. in GSMPhone.java In: </P>
<P><PRE class=java name="code">GSMCallTracker mCT;
public Connection dial(String dialString) throws CallStateException {
return dial(dialString, null);
}
public Connection dial(String dialString, UUSInfo uusInfo) throws CallStateException {
.......
mCT.dial(.......);
}</PRE><P></P>
<P> Continue to call GSMCallTracker.java In the dial() Methods: </P>
<P><PRE class=cpp name="code">GSMCallTracker.java :
GSMCallTracker(GSMPhone phone) {
cm = phone.mCM;
}
Connection dial(String dialString, int clirMode, UUSInfo uusInfo) {
<SPAN style="COLOR: #ff0000">cm.dial(........);</SPAN>
}</PRE> tracking mCM, found :<P></P>
<P>public CommandsInterface mCM;</P>
<P> so GSMCallTracker hold CommandsInterface Objects, that is, RIL.Java Class object, so "cm.dial(....)" That is called RIL The class object dial() Methods. </P>
<P>9. RIL.java</P>
<P>BOSS Appear. </P>
<P>RIL Object is responsible for following the client's call request 1 The specified format is sent to "rild"socket, At this point, the request process is complete. </P>
</PRE>