How an activity is created
24 Nov 2013
Interfaces
+-------------------------------+
| IBinder |
| | |
| +- +transact() |
| +- +onTransact() |
| |
+-------------------------------+
+-------------------------------+
| IActivityManager |
| | |
| +- +startActivity() |
| |
+-------------------------------+
code flow
To achieve this, I have spent a whole day in VIM, :).
// We start from here
Activity
|
+- startActivity()
|
+- startActivityForResult()
|
+- mInstrumentation.execStartActivity
|
|
Instrumentation |
| |
+- execStartActivity() <------+
| |
| +- ActivityManagerNative.getDefault().startActivity(); ---+
| | |
+- newActivity() | |
| | | |
| | +-------------------------+ | |
| | | | | |
| +->| Activity.newInstance() | | |
| | | | |
| +-------------------------+ | |
| | |
+- callActivityOnCreate() | |
| | |
| | |
| +--------------------------+ | |
| | | | |
+->| Activity.performCreate() | | |
| | | |
+------------------------- + | |
| |
| |
| |
+----|> IBinder, IActivityManager | |
| | |
ActivityManagerNative | |
^ | | |
| +- -gDefault | |
| | | |
| +- +getDefault(): <---------+ |
| | | |
| | gDefault.get() |
| | | |
| | | |
| | +-------+--------------------------------------------+ |
| | | | |
| | | ActivityManagerProxy ------- |> IActivityManager | |
| | | | | |
| | | +- -mRemote: ActivityManagerService | |
| | | | | |
| | | +- +startActivity() <---------------------- | -+
| | | | |
| | | + mRemote.transact() |
| | | | |
| | +--------------------------- | ----------------------+
| | |
| | +--------------------------+
| | |
| | v
| +- +transact() --------------------------+
| | |
| | |
| +- +onTransact() <-----------------+ |
| | | |
| +- call: startActivity()----|-----|-----+
| | | |
| | | |
ActivityManagerService | | |
| | | |
+- -mMainStack:ActivityStack | | |
| | | |
+- +onTransact() <-----------------------+ |
| | | |
| +- super::onTransact()------+ |
| |
+- +startActivity() <--------------------------+
| |
| +- startActivityAsUser()
| |
| +- mMainStack.startActivityMayWait()
| |
+- +startProcessLocked() <----------------|---------------------+
| ProcessRecord app; | |
| Process.start( | |
| "android.app.ActivityThread", | |
| app.processName, ... --------------|-------------+ |
| | | |
+- attachApplication <------------------------|-------------|-------|---------+
| | | | |
+- attachApplicationLocked() | | | |
| | | | |
+- mMainStack.realStartActivityLocked(); -----------------------------+ |
| | | | |
ActivityStack | | | | |
| | | | | |
|- startActivityMayWait() <-------------------------+ | | | |
| | | | | |
| +- startActivityLocked(IApplicationThread caller, ... | | | |
| | | | | |
| +- startActivityUncheckedLocked | | | |
| | | | | |
| +- startActivityLocked(ActivityRecord r,... | | | |
| | | | | |
| +- resumeTopActivityLocked | | | |
| | | + | |
| +- mService.startProcessLocked: finnaly call this function. | |
| | | |
+- realStartActivityLocked() <--------------------------------------------------+ |
| | |
+ call: ActivityThread::scheduleLaunchActivity() -----------------------+ |
| | |
| | |
Process <- android.os | | |
| | | |
+- start() <-----------------------------------------------------+ | |
| | |
+- startViaZygote() | |
| | |
+- zygoteSendArgsAndGetResult() <---+ | |
| | |
| | |
ActivityThread | | |
| Socket, Unix domain TCP | | |
+- main() <------------------------------+ | |
| | | |
| +- attach() | |
| | | |
| +- ActivityManagerNative.getDefault().attachApplication() | |
| | | |
| ... a lot of call stacks | |
| | | |
| + ActivityManagerService::attachApplication() ---------------|-------+
| |
+- scheduleLaunchActivity() <--------------------------------------------- +
| |
| +- queueOrSendMessage(H.LAUNCH_ACTIVITY, r);
|
+- -H -> Handler
| |
| + handleMessage() --------+
| |
+- handleLaunchActivity() <----------+
|
+- performLaunchActivity()
|
+- mInstrumentation.newActivity()
+- mInstrumentation.callActivityOnCreate()
Finally
When we call startActivity(), ActivityManagerProxy will communicate with Zyogte by Unix domain TCP.
Zyogte will invoke ActivityThread to process the request.
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