Android4.4 framework分析——startService的創建過程

我們常用context.startService()來啟動一個service，下面來分析一下這個service的啟動過程，下圖是service啟動的序列圖:

step2，mBase.startService()中mBase定義為Context，它的真實實現是ContextImpl對象(看名字就知道是Context的實現類)。

step4，ActivityManagerNative.getDefault().startService()中ActivityManagerNative.getDefault()得到的是ActivityManagerService的代理對象ActivityManagerProxy。

step9，bringUpServiceLocked()中如果service所在進程(android:process屬性中聲明)已啟動，則直接使用realStartServiceLocked()啟動service，否則執行step10～step30先啟動新進程，新進程的啟動過程分析，可以查看 Android應用程序進程啟動過程的源代碼分析 。

step18，mPendingServices.add()中會將這個要啟動的service加入到mPendingServices這個待啟動列表中，待新進程啟動後會取出，在此時，step37中mPendingServices.get(i)。

step39，realStartServiceLocked()真的要啟動service了。<喎?/kf/ware/vc/" target="_blank" class="keylink">vcD4KPHA+c3RlcDQyo6xzY2hlZHVsZUNyZWF0ZVNlcnZpY2UoKdKqtffTw1NlcnZpY2W1xG9uQ3JlYXRltLS9qHNlcnZpY2XBy6GjPC9wPgo8cD5zdGVwNTOjrHNjaGVkdWxlU2VydmljZUFyZ3MoKbX308NTZXJ2aWNltcRvblN0YXJ0Q29tbWFuZCgp1rTQ0HNlcnZpY2WhozwvcD4KPHA+PGJyPgo8L3A+CjxwPs/Cw+bKx0FjdGl2aXR5VGhyZWFktcS0+sLrxqy2zqO6PC9wPgo8cD48cHJlIGNsYXNzPQ=="brush:java;"> private class H extends Handler { public static final int LAUNCH_ACTIVITY = 100; public static final int PAUSE_ACTIVITY = 101; public static final int PAUSE_ACTIVITY_FINISHING= 102; public static final int STOP_ACTIVITY_SHOW = 103; public static final int STOP_ACTIVITY_HIDE = 104; public static final int SHOW_WINDOW = 105; public static final int HIDE_WINDOW = 106; public static final int RESUME_ACTIVITY = 107; public static final int SEND_RESULT = 108; public static final int DESTROY_ACTIVITY = 109; public static final int BIND_APPLICATION = 110; public static final int EXIT_APPLICATION = 111; public static final int NEW_INTENT = 112; public static final int RECEIVER = 113; public static final int CREATE_SERVICE = 114; public static final int SERVICE_ARGS = 115; public static final int STOP_SERVICE = 116; public static final int REQUEST_THUMBNAIL = 117; public static final int CONFIGURATION_CHANGED = 118; public static final int CLEAN_UP_CONTEXT = 119; public static final int GC_WHEN_IDLE = 120; public static final int BIND_SERVICE = 121; public static final int UNBIND_SERVICE = 122; public static final int DUMP_SERVICE = 123; public static final int LOW_MEMORY = 124; public static final int ACTIVITY_CONFIGURATION_CHANGED = 125; public static final int RELAUNCH_ACTIVITY = 126; public static final int PROFILER_CONTROL = 127; public static final int CREATE_BACKUP_AGENT = 128; public static final int DESTROY_BACKUP_AGENT = 129; public static final int SUICIDE = 130; public static final int REMOVE_PROVIDER = 131; public static final int ENABLE_JIT = 132; public static final int DISPATCH_PACKAGE_BROADCAST = 133; public static final int SCHEDULE_CRASH = 134; public static final int DUMP_HEAP = 135; public static final int DUMP_ACTIVITY = 136; public static final int SLEEPING = 137; public static final int SET_CORE_SETTINGS = 138; public static final int UPDATE_PACKAGE_COMPATIBILITY_INFO = 139; public static final int TRIM_MEMORY = 140; public static final int DUMP_PROVIDER = 141; public static final int UNSTABLE_PROVIDER_DIED = 142; public static final int REQUEST_ASSIST_CONTEXT_EXTRAS = 143; public static final int TRANSLUCENT_CONVERSION_COMPLETE = 144; public static final int INSTALL_PROVIDER = 145; String codeToString(int code) { if (DEBUG_MESSAGES) { switch (code) { case LAUNCH_ACTIVITY: return "LAUNCH_ACTIVITY"; case PAUSE_ACTIVITY: return "PAUSE_ACTIVITY"; case PAUSE_ACTIVITY_FINISHING: return "PAUSE_ACTIVITY_FINISHING"; case STOP_ACTIVITY_SHOW: return "STOP_ACTIVITY_SHOW"; case STOP_ACTIVITY_HIDE: return "STOP_ACTIVITY_HIDE"; case SHOW_WINDOW: return "SHOW_WINDOW"; case HIDE_WINDOW: return "HIDE_WINDOW"; case RESUME_ACTIVITY: return "RESUME_ACTIVITY"; case SEND_RESULT: return "SEND_RESULT"; case DESTROY_ACTIVITY: return "DESTROY_ACTIVITY"; case BIND_APPLICATION: return "BIND_APPLICATION"; case EXIT_APPLICATION: return "EXIT_APPLICATION"; case NEW_INTENT: return "NEW_INTENT"; case RECEIVER: return "RECEIVER"; case CREATE_SERVICE: return "CREATE_SERVICE"; case SERVICE_ARGS: return "SERVICE_ARGS"; case STOP_SERVICE: return "STOP_SERVICE"; case REQUEST_THUMBNAIL: return "REQUEST_THUMBNAIL"; case CONFIGURATION_CHANGED: return "CONFIGURATION_CHANGED"; case CLEAN_UP_CONTEXT: return "CLEAN_UP_CONTEXT"; case GC_WHEN_IDLE: return "GC_WHEN_IDLE"; case BIND_SERVICE: return "BIND_SERVICE"; case UNBIND_SERVICE: return "UNBIND_SERVICE"; case DUMP_SERVICE: return "DUMP_SERVICE"; case LOW_MEMORY: return "LOW_MEMORY"; case ACTIVITY_CONFIGURATION_CHANGED: return "ACTIVITY_CONFIGURATION_CHANGED"; case RELAUNCH_ACTIVITY: return "RELAUNCH_ACTIVITY"; case PROFILER_CONTROL: return "PROFILER_CONTROL"; case CREATE_BACKUP_AGENT: return "CREATE_BACKUP_AGENT"; case DESTROY_BACKUP_AGENT: return "DESTROY_BACKUP_AGENT"; case SUICIDE: return "SUICIDE"; case REMOVE_PROVIDER: return "REMOVE_PROVIDER"; case ENABLE_JIT: return "ENABLE_JIT"; case DISPATCH_PACKAGE_BROADCAST: return "DISPATCH_PACKAGE_BROADCAST"; case SCHEDULE_CRASH: return "SCHEDULE_CRASH"; case DUMP_HEAP: return "DUMP_HEAP"; case DUMP_ACTIVITY: return "DUMP_ACTIVITY"; case SLEEPING: return "SLEEPING"; case SET_CORE_SETTINGS: return "SET_CORE_SETTINGS"; case UPDATE_PACKAGE_COMPATIBILITY_INFO: return "UPDATE_PACKAGE_COMPATIBILITY_INFO"; case TRIM_MEMORY: return "TRIM_MEMORY"; case DUMP_PROVIDER: return "DUMP_PROVIDER"; case UNSTABLE_PROVIDER_DIED: return "UNSTABLE_PROVIDER_DIED"; case REQUEST_ASSIST_CONTEXT_EXTRAS: return "REQUEST_ASSIST_CONTEXT_EXTRAS"; case TRANSLUCENT_CONVERSION_COMPLETE: return "TRANSLUCENT_CONVERSION_COMPLETE"; case INSTALL_PROVIDER: return "INSTALL_PROVIDER"; } } return Integer.toString(code); } public void handleMessage(Message msg) { if (DEBUG_MESSAGES) Slog.v(TAG, ">>> handling: " + codeToString(msg.what)); switch (msg.what) { case LAUNCH_ACTIVITY: { Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityStart"); ActivityClientRecord r = (ActivityClientRecord)msg.obj; r.packageInfo = getPackageInfoNoCheck( r.activityInfo.applicationInfo, r.compatInfo); handleLaunchActivity(r, null); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); } break; case RELAUNCH_ACTIVITY: { Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityRestart"); ActivityClientRecord r = (ActivityClientRecord)msg.obj; handleRelaunchActivity(r); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); } break; case PAUSE_ACTIVITY: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityPause"); handlePauseActivity((IBinder)msg.obj, false, msg.arg1 != 0, msg.arg2); maybeSnapshot(); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case PAUSE_ACTIVITY_FINISHING: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityPause"); handlePauseActivity((IBinder)msg.obj, true, msg.arg1 != 0, msg.arg2); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case STOP_ACTIVITY_SHOW: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityStop"); handleStopActivity((IBinder)msg.obj, true, msg.arg2); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case STOP_ACTIVITY_HIDE: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityStop"); handleStopActivity((IBinder)msg.obj, false, msg.arg2); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case SHOW_WINDOW: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityShowWindow"); handleWindowVisibility((IBinder)msg.obj, true); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case HIDE_WINDOW: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityHideWindow"); handleWindowVisibility((IBinder)msg.obj, false); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case RESUME_ACTIVITY: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityResume"); handleResumeActivity((IBinder)msg.obj, true, msg.arg1 != 0, true); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case SEND_RESULT: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityDeliverResult"); handleSendResult((ResultData)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case DESTROY_ACTIVITY: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityDestroy"); handleDestroyActivity((IBinder)msg.obj, msg.arg1 != 0, msg.arg2, false); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case BIND_APPLICATION: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "bindApplication"); AppBindData data = (AppBindData)msg.obj; handleBindApplication(data); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case EXIT_APPLICATION: if (mInitialApplication != null) { mInitialApplication.onTerminate(); } Looper.myLooper().quit(); break; case NEW_INTENT: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityNewIntent"); handleNewIntent((NewIntentData)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case RECEIVER: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "broadcastReceiveComp"); handleReceiver((ReceiverData)msg.obj); maybeSnapshot(); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case CREATE_SERVICE: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "serviceCreate"); handleCreateService((CreateServiceData)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case BIND_SERVICE: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "serviceBind"); handleBindService((BindServiceData)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case UNBIND_SERVICE: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "serviceUnbind"); handleUnbindService((BindServiceData)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case SERVICE_ARGS: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "serviceStart"); handleServiceArgs((ServiceArgsData)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case STOP_SERVICE: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "serviceStop"); handleStopService((IBinder)msg.obj); maybeSnapshot(); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case REQUEST_THUMBNAIL: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "requestThumbnail"); handleRequestThumbnail((IBinder)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case CONFIGURATION_CHANGED: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "configChanged"); mCurDefaultDisplayDpi = ((Configuration)msg.obj).densityDpi; handleConfigurationChanged((Configuration)msg.obj, null); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case CLEAN_UP_CONTEXT: ContextCleanupInfo cci = (ContextCleanupInfo)msg.obj; cci.context.performFinalCleanup(cci.who, cci.what); break; case GC_WHEN_IDLE: scheduleGcIdler(); break; case DUMP_SERVICE: handleDumpService((DumpComponentInfo)msg.obj); break; case LOW_MEMORY: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "lowMemory"); handleLowMemory(); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case ACTIVITY_CONFIGURATION_CHANGED: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "activityConfigChanged"); handleActivityConfigurationChanged((IBinder)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case PROFILER_CONTROL: handleProfilerControl(msg.arg1 != 0, (ProfilerControlData)msg.obj, msg.arg2); break; case CREATE_BACKUP_AGENT: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backupCreateAgent"); handleCreateBackupAgent((CreateBackupAgentData)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case DESTROY_BACKUP_AGENT: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backupDestroyAgent"); handleDestroyBackupAgent((CreateBackupAgentData)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case SUICIDE: Process.killProcess(Process.myPid()); break; case REMOVE_PROVIDER: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "providerRemove"); completeRemoveProvider((ProviderRefCount)msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case ENABLE_JIT: ensureJitEnabled(); break; case DISPATCH_PACKAGE_BROADCAST: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "broadcastPackage"); handleDispatchPackageBroadcast(msg.arg1, (String[])msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case SCHEDULE_CRASH: throw new RemoteServiceException((String)msg.obj); case DUMP_HEAP: handleDumpHeap(msg.arg1 != 0, (DumpHeapData)msg.obj); break; case DUMP_ACTIVITY: handleDumpActivity((DumpComponentInfo)msg.obj); break; case DUMP_PROVIDER: handleDumpProvider((DumpComponentInfo)msg.obj); break; case SLEEPING: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "sleeping"); handleSleeping((IBinder)msg.obj, msg.arg1 != 0); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case SET_CORE_SETTINGS: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "setCoreSettings"); handleSetCoreSettings((Bundle) msg.obj); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case UPDATE_PACKAGE_COMPATIBILITY_INFO: handleUpdatePackageCompatibilityInfo((UpdateCompatibilityData)msg.obj); break; case TRIM_MEMORY: Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "trimMemory"); handleTrimMemory(msg.arg1); Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER); break; case UNSTABLE_PROVIDER_DIED: handleUnstableProviderDied((IBinder)msg.obj, false); break; case REQUEST_ASSIST_CONTEXT_EXTRAS: handleRequestAssistContextExtras((RequestAssistContextExtras)msg.obj); break; case TRANSLUCENT_CONVERSION_COMPLETE: handleTranslucentConversionComplete((IBinder)msg.obj, msg.arg1 == 1); break; case INSTALL_PROVIDER: handleInstallProvider((ProviderInfo) msg.obj); break; } if (DEBUG_MESSAGES) Slog.v(TAG, "<<< done: " + codeToString(msg.what)); } private void maybeSnapshot() { if (mBoundApplication != null && SamplingProfilerIntegration.isEnabled()) { // convert the *private* ActivityThread.PackageInfo to *public* known // android.content.pm.PackageInfo String packageName = mBoundApplication.info.mPackageName; android.content.pm.PackageInfo packageInfo = null; try { Context context = getSystemContext(); if(context == null) { Log.e(TAG, "cannot get a valid context"); return; } PackageManager pm = context.getPackageManager(); if(pm == null) { Log.e(TAG, "cannot get a valid PackageManager"); return; } packageInfo = pm.getPackageInfo( packageName, PackageManager.GET_ACTIVITIES); } catch (NameNotFoundException e) { Log.e(TAG, "cannot get package info for " + packageName, e); } SamplingProfilerIntegration.writeSnapshot(mBoundApplication.processName, packageInfo); } } }這部分代碼是ActivityThread的一個內部類H，裡面定義了activity、service等啟動、銷毀等事件的響應，也就是說activity、service的啟動、銷毀都是在ActivityThread中進行的。

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未完待續，有不對的地方，請指正。