Android 9.0 APP 啓動流程分析 (進程建立 ,ActivityThread 建立 ,Application建立,Activity的建立,)
1.APP啓動優化
1.系統啓動流程
學習APP啓動以前,先大概瞭解下Android系統啓動的流程,流程圖以下:java
Android系統在按下電源鍵時 引導芯片的代碼加載引導程序Boot Loader到RAM中去執行 ,BootLoader把操做系統拉起來 ,Linux 內核啓動開始系統設置，找到一個init.rc文件啓動初始化進程,init進程初始化和啓動屬性服務，以後開啓Zygote進程,Zygote開始建立JVM並註冊JNI方法，開啓SystemServer,SystemService中有ServiceThread內部類在systemService初始化的main函數中會初始化這個線程,在線程中接下來會啓動Binder線程池和SystemServiceManager,並啓動各類服務,並且launcher的啓動也是在設個run方法中調用ActivityManagerService的 systemReady,在設個方法中調用ActivityStack 的resumeTopActivityLocked ,以後的邏輯也就是APP的地洞流程 ,這樣系統開機就完成,咱們能夠點擊launcher 上的app圖標去開啓appandroid
2.App啓動流程分析
啓動過程當中會分析 進程建立 ,ActivityThread 建立 ,Application建立,Activity的建立,下面是大概的執行步驟web
1. Activity : startActivity-->startActivityForResult
2. Instrumentation:execStartActivity()-->ActivityManagerService :startActivity ()-->startActivityAsUser()
3. ActivityStarter:execute()-->startActivity()-->startActivityUnchecked ()
4. ActivityStackSupervisor:resumeFocusedStackTopActivityLocked()
5. ActivityStarter :resumeTopActivityUncheckedLocked()-->resumeTopActivityInnerLocked()
7. ActivityStackSupervisor :startSpecificActivityLocked() --> realStartActivityLocked() 這個方法是啓動Activity的 第一次建立APP 會先執行第8步 建立進程
8. ActivityManagerService :startProcessLocked()-->startProcess()
9. Process :start ()-->ZygoteProcess:start()-->startViaZygote()-->openZygoteSocketIfNeeded()
10. ZygoteState:connect()-->zygote :main()-->zygoteServer:runSelectLoop()
11. ZygoteConnection:processOneCommand()--->handleChildProc()
12. ZtgoteInit: zygoteInit()
13. RuntimeInit: applicationInit() 這裏app的進程建立成功ActivityThread的main函數會被調用
14.ActivityThread: main()-->attach()
16. ActivityManagerService : attachApplication()
17.ApplicationThread: bindApplication() Application在這裏建立
18. ActivityStackSupervisor: attachApplicationLocked()--->realStartActivityLocked()
19. ClientTransaction--->schedule()
20. ActivityThread: scheduleTransaction()
20. TransactionExecutor:--execute(transaction)-->executeCallbacks()-->LaunchActivityItem:execute()
21. ActivityThread: handleLaunchActivity--->performLaunchActivity
詳細源碼展現以下windows
1. Activity 啓動
桌面launcher 點擊圖標會執行 Launcher.java 中的onClick(View view)-->startActivitySafely(v, intent, tag)-->startActivity(View v, Intent intent, Object tag) 這裏邏輯走完就直接進入了Activity的startActivity(Intent intent) 方法緩存
/**
2031 * Launches the intent referred by the clicked shortcut.
2032 *
2033 * @param v The view representing the clicked shortcut.
2034 */
2035 public void onClick(View v) {
2036 .....
2045
2046 Object tag = v.getTag();
2047 if (tag instanceof ShortcutInfo) {
2048 ..........
2054 //=================注意===================
2055 boolean success = startActivitySafely(v, intent, tag);
2056
2057 .......
2061 }
2072 }
boolean startActivitySafely(View v, Intent intent, Object tag) {
2216 boolean success = false;
2217 try {
//=================注意===================
2218 success = startActivity(v, intent, tag);
2219 } catch (ActivityNotFoundException e) {
2220 Toast.makeText(this, R.string.activity_not_found, Toast.LENGTH_SHORT).show();
2221 Log.e(TAG, "Unable to launch. tag=" + tag + " intent=" + intent, e);
2222 }
2223 return success;
2224 }
boolean startActivity(View v, Intent intent, Object tag) {
2175 intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
2176
2184 this.getSystemService(Context.LAUNCHER_APPS_SERVICE);
2185 ......
2197 if (user == null || user.equals(android.os.Process.myUserHandle())) {
//=================注意===================
2198 startActivity(intent);
2199 } else {
2200 launcherApps.startMainActivity(intent.getComponent(), user,
2201 intent.getSourceBounds(), null);
2202 }
2203 .......
2204
2212 return false;
2213 }
複製代碼
Activity : startActivity-->startActivityForResult
第一次進來 mParent爲null 直接調用Instrumentation 的 execStartActivitybash
@Override
public void startActivity(Intent intent) {
this.startActivity(intent, null);
}
public void startActivityForResult(@RequiresPermission Intent intent, int requestCode,
@Nullable Bundle options) {
if (mParent == null) {
options = transferSpringboardActivityOptions(options);
Instrumentation.ActivityResult ar =
mInstrumentation.execStartActivity(
this, mMainThread.getApplicationThread(), mToken, this,
intent, requestCode, options);
if (ar != null) {
mMainThread.sendActivityResult(
mToken, mEmbeddedID, requestCode, ar.getResultCode(),
ar.getResultData());
}
if (requestCode >= 0) {
// If this start is requesting a result, we can avoid making
// the activity visible until the result is received. Setting
// this code during onCreate(Bundle savedInstanceState) or onResume() will keep the
// activity hidden during this time, to avoid flickering.
// This can only be done when a result is requested because
// that guarantees we will get information back when the
// activity is finished, no matter what happens to it.
mStartedActivity = true;
}
cancelInputsAndStartExitTransition(options);
// TODO Consider clearing/flushing other event sources and events for child windows.
} else {
if (options != null) {
mParent.startActivityFromChild(this, intent, requestCode, options);
} else {
// Note we want to go through this method for compatibility with
// existing applications that may have overridden it.
mParent.startActivityFromChild(this, intent, requestCode);
}
}
}
public void startActivityForResult(@RequiresPermission Intent intent, int requestCode,
@Nullable Bundle options) {
if (mParent == null) {
options = transferSpringboardActivityOptions(options);
Instrumentation.ActivityResult ar =
mInstrumentation.execStartActivity(
this, mMainThread.getApplicationThread(), mToken, this,
intent, requestCode, options);
......
}
複製代碼
Instrumentation:execStartActivity()-->ActivityManagerService :startActivity ()-->startActivityAsUser()
public ActivityResult execStartActivity(
Context who, IBinder contextThread, IBinder token, Activity target,
Intent intent, int requestCode, Bundle options) {
....
try {
intent.migrateExtraStreamToClipData();
intent.prepareToLeaveProcess(who);
//=================注意---------------
int result = ActivityManager.getService()
.startActivity(whoThread, who.getBasePackageName(), intent,
intent.resolveTypeIfNeeded(who.getContentResolver()),
token, target != null ? target.mEmbeddedID : null,
requestCode, 0, null, options);
checkStartActivityResult(result, intent);
} catch (RemoteException e) {
throw new RuntimeException("Failure from system", e);
}
return null;
}
複製代碼
這裏的ActivityManager.getService() 獲取到的是ActivityManagerService 實例 會執行到獲取到的是ActivityManagerService裏的startActivityapp
@Override
public final int startActivity(IApplicationThread caller, String callingPackage,
Intent intent, String resolvedType, IBinder resultTo, String resultWho, int requestCode,
int startFlags, ProfilerInfo profilerInfo, Bundle bOptions) {
return startActivityAsUser(caller, callingPackage, intent, resolvedType, resultTo,
resultWho, requestCode, startFlags, profilerInfo, bOptions,
UserHandle.getCallingUserId());
}
@Override
public final int startActivityAsUser(IApplicationThread caller, String callingPackage,
Intent intent, String resolvedType, IBinder resultTo, String resultWho, int requestCode,
int startFlags, ProfilerInfo profilerInfo, Bundle bOptions, int userId) {
return startActivityAsUser(caller, callingPackage, intent, resolvedType, resultTo,
resultWho, requestCode, startFlags, profilerInfo, bOptions, userId,
true /*validateIncomingUser*/);
}
public final int startActivityAsUser(IApplicationThread caller, String callingPackage,
Intent intent, String resolvedType, IBinder resultTo, String resultWho, int requestCode,
int startFlags, ProfilerInfo profilerInfo, Bundle bOptions, int userId,
boolean validateIncomingUser) {
enforceNotIsolatedCaller("startActivity");
userId = mActivityStartController.checkTargetUser(userId, validateIncomingUser,
Binder.getCallingPid(), Binder.getCallingUid(), "startActivityAsUser");
// TODO: Switch to user app stacks here.
return mActivityStartController.obtainStarter(intent, "startActivityAsUser")
.setCaller(caller)
.setCallingPackage(callingPackage)
.setResolvedType(resolvedType)
.setResultTo(resultTo)
.setResultWho(resultWho)
.setRequestCode(requestCode)
.setStartFlags(startFlags)
.setProfilerInfo(profilerInfo)
.setActivityOptions(bOptions)
.setMayWait(userId)
.execute();
}
複製代碼
ActivityStarter:execute()-->startActivity()-->startActivityUnchecked (
上面代碼最後會執行到 ActivityStarter的execute()方法less
int execute() {
try {
// TODO(b/64750076): Look into passing request directly to these methods to allow
// for transactional diffs and preprocessing.
if (mRequest.mayWait) {
return startActivityMayWait(mRequest.caller, mRequest.callingUid,
mRequest.callingPackage, mRequest.intent, mRequest.resolvedType,
mRequest.voiceSession, mRequest.voiceInteractor, mRequest.resultTo,
mRequest.resultWho, mRequest.requestCode, mRequest.startFlags,
mRequest.profilerInfo, mRequest.waitResult, mRequest.globalConfig,
mRequest.activityOptions, mRequest.ignoreTargetSecurity, mRequest.userId,
mRequest.inTask, mRequest.reason,
mRequest.allowPendingRemoteAnimationRegistryLookup);
} else {
return startActivity(mRequest.caller, mRequest.intent, mRequest.ephemeralIntent,
mRequest.resolvedType, mRequest.activityInfo, mRequest.resolveInfo,
mRequest.voiceSession, mRequest.voiceInteractor, mRequest.resultTo,
mRequest.resultWho, mRequest.requestCode, mRequest.callingPid,
mRequest.callingUid, mRequest.callingPackage, mRequest.realCallingPid,
mRequest.realCallingUid, mRequest.startFlags, mRequest.activityOptions,
mRequest.ignoreTargetSecurity, mRequest.componentSpecified,
mRequest.outActivity, mRequest.inTask, mRequest.reason,
mRequest.allowPendingRemoteAnimationRegistryLookup);
}
} finally {
onExecutionComplete();
}
}
複製代碼
這裏的if 條件最終還會執行到else裏的startActivity 方法通過再次調用兩個startActivity 會走到startActivityUnchecked 方法socket
..............
if (mTargetStack.isFocusable() && !mSupervisor.isFocusedStack(mTargetStack)) {
mTargetStack.moveToFront("startActivityUnchecked");
}
//在方法結尾處有這個方法
mSupervisor.resumeFocusedStackTopActivityLocked(mTargetStack, mStartActivity,
mOptions);
}
...........
複製代碼
ActivityStackSupervisor:resumeFocusedStackTopActivityLocked()
ActivityStackSupervisor->resumeFocusedStackTopActivityLockedide
boolean resumeFocusedStackTopActivityLocked(
ActivityStack targetStack, ActivityRecord target, ActivityOptions targetOptions) {
if (!readyToResume()) {
return false;
}
if (targetStack != null && isFocusedStack(targetStack)) {
return targetStack.resumeTopActivityUncheckedLocked(target, targetOptions);
}
final ActivityRecord r = mFocusedStack.topRunningActivityLocked();
if (r == null || !r.isState(RESUMED)) {
//=============注意===========
mFocusedStack.resumeTopActivityUncheckedLocked(null, null);
} else if (r.isState(RESUMED)) {
// Kick off any lingering app transitions form the MoveTaskToFront operation.
mFocusedStack.executeAppTransition(targetOptions);
}
return false;
}
複製代碼
ActivityStarter :resumeTopActivityUncheckedLocked()-->resumeTopActivityInnerLocked
執行完ActivityStackSupervisor 的resumeFocusedStackTopActivityLocked 又返回到ActivityStarter 中調用resumeTopActivityUncheckedLocked方法
boolean resumeTopActivityUncheckedLocked(ActivityRecord prev, ActivityOptions options) {
.............
try {
// Protect against recursion.
mStackSupervisor.inResumeTopActivity = true;
//========注意============
result = resumeTopActivityInnerLocked(prev, options);
...........................
} finally {
mStackSupervisor.inResumeTopActivity = false;
}
return result;
}
private boolean resumeTopActivityInnerLocked(ActivityRecord prev, ActivityOptions options) {
..................................
} else {
// Whoops, need to restart this activity!
if (!next.hasBeenLaunched) {
next.hasBeenLaunched = true;
} else {
if (SHOW_APP_STARTING_PREVIEW) {
next.showStartingWindow(null /* prev */, false /* newTask */,
false /* taskSwich */);
}
if (DEBUG_SWITCH) Slog.v(TAG_SWITCH, "Restarting: " + next);
}
if (DEBUG_STATES) Slog.d(TAG_STATES, "resumeTopActivityLocked: Restarting " + next);
//====================注意====================
mStackSupervisor.startSpecificActivityLocked(next, true, true);
}
if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
return true;
}
複製代碼
ActivityStackSupervisor :startSpecificActivityLocked() --> realStartActivityLocked(啓動activity)
接着在執行執行完ActivityStackSupervisor 中的startSpecificActivityLocked方法,這個方法裏會去判斷ProcessRecord 是不是空 若是是空會去初始化這個進程 而且建立一個ActivityThread 在這裏就爲一個新的程序建立一個主線程,若是當前進程存在會執行 realStartActivityLocked 方法去打對應的Activity頁面,咱們首先分應用啓動時ProcessRecord 爲null的狀況
void startSpecificActivityLocked(ActivityRecord r,
boolean andResume, boolean checkConfig) {
// Is this activity's application already running? ProcessRecord app = mService.getProcessRecordLocked(r.processName, r.info.applicationInfo.uid, true); getLaunchTimeTracker().setLaunchTime(r); if (app != null && app.thread != null) { try { if ((r.info.flags&ActivityInfo.FLAG_MULTIPROCESS) == 0 || !"android".equals(r.info.packageName)) { // Don't add this if it is a platform component that is marked
// to run in multiple processes, because this is actually
// part of the framework so doesn't make sense to track as a // separate apk in the process. app.addPackage(r.info.packageName, r.info.applicationInfo.longVersionCode, mService.mProcessStats); } realStartActivityLocked(r, app, andResume, checkConfig); return; } catch (RemoteException e) { Slog.w(TAG, "Exception when starting activity " + r.intent.getComponent().flattenToShortString(), e); } // If a dead object exception was thrown -- fall through to // restart the application. } //目標進程不存在建立對應進程 mService.startProcessLocked(r.processName, r.info.applicationInfo, true, 0, "activity", r.intent.getComponent(), false, false, true); } 複製代碼
2.進程建立 和ActivityThread 的調用
ActivityManagerService :startProcessLocked()-->startProcess()
ActivityManagerService中去建立進程,
@GuardedBy("this")
final ProcessRecord startProcessLocked(String processName,
ApplicationInfo info, boolean knownToBeDead, int intentFlags,
String hostingType, ComponentName hostingName, boolean allowWhileBooting,
boolean isolated, boolean keepIfLarge) {
return startProcessLocked(processName, info, knownToBeDead, intentFlags, hostingType,
hostingName, allowWhileBooting, isolated, 0 /* isolatedUid */, keepIfLarge,
null /* ABI override */, null /* entryPoint */, null /* entryPointArgs */,
null /* crashHandler */);
}
@GuardedBy("this")
final ProcessRecord startProcessLocked(String processName, ApplicationInfo info,
boolean knownToBeDead, int intentFlags, String hostingType, ComponentName hostingName,
boolean allowWhileBooting, boolean isolated, int isolatedUid, boolean keepIfLarge,
String abiOverride, String entryPoint, String[] entryPointArgs, Runnable crashHandler) {
...................
//===========會先創穫得ProcessRecord 若是緩存沒有會新建一個 賦值到app上
checkTime(startTime, "startProcess: stepping in to startProcess");
//==============注意===========
final boolean success = startProcessLocked(app, hostingType, hostingNameStr, abiOverride);
checkTime(startTime, "startProcess: done starting proc!");
return success ? app : null;
}
..........................
後續會調用到第三個startProcessLocked
............................
private boolean startProcessLocked(String hostingType, String hostingNameStr, String entryPoint,
ProcessRecord app, int uid, int[] gids, int runtimeFlags, int mountExternal,
String seInfo, String requiredAbi, String instructionSet, String invokeWith,
long startTime) {
app.pendingStart = true;
app.killedByAm = false;
app.removed = false;
app.killed = false;
final long startSeq = app.startSeq = ++mProcStartSeqCounter;
app.setStartParams(uid, hostingType, hostingNameStr, seInfo, startTime);
if (mConstants.FLAG_PROCESS_START_ASYNC) {
if (DEBUG_PROCESSES) Slog.i(TAG_PROCESSES,
"Posting procStart msg for " + app.toShortString());
mProcStartHandler.post(() -> {
try {
synchronized (ActivityManagerService.this) {
final String reason = isProcStartValidLocked(app, startSeq);
if (reason != null) {
Slog.w(TAG_PROCESSES, app + " not valid anymore,"
+ " don't start process, " + reason);
app.pendingStart = false;
return;
}
app.usingWrapper = invokeWith != null
|| SystemProperties.get("wrap." + app.processName) != null;
mPendingStarts.put(startSeq, app);
}
//=====================注意
final ProcessStartResult startResult = startProcess(app.hostingType, entryPoint,
app, app.startUid, gids, runtimeFlags, mountExternal, app.seInfo,
requiredAbi, instructionSet, invokeWith, app.startTime);
synchronized (ActivityManagerService.this) {
handleProcessStartedLocked(app, startResult, startSeq);
}
} catch (RuntimeException e) {
synchronized (ActivityManagerService.this) {
Slog.e(TAG, "Failure starting process " + app.processName, e);
mPendingStarts.remove(startSeq);
app.pendingStart = false;
forceStopPackageLocked(app.info.packageName, UserHandle.getAppId(app.uid),
false, false, true, false, false,
UserHandle.getUserId(app.userId), "start failure");
}
}
});
return true;
} else {
try {
//=====================注意
final ProcessStartResult startResult = startProcess(hostingType, entryPoint, app,
uid, gids, runtimeFlags, mountExternal, seInfo, requiredAbi, instructionSet,
invokeWith, startTime);
handleProcessStartedLocked(app, startResult.pid, startResult.usingWrapper,
startSeq, false);
} catch (RuntimeException e) {
Slog.e(TAG, "Failure starting process " + app.processName, e);
app.pendingStart = false;
forceStopPackageLocked(app.info.packageName, UserHandle.getAppId(app.uid),
false, false, true, false, false,
UserHandle.getUserId(app.userId), "start failure");
}
return app.pid > 0;
}
}
private ProcessStartResult startProcess(String hostingType, String entryPoint,
ProcessRecord app, int uid, int[] gids, int runtimeFlags, int mountExternal,
String seInfo, String requiredAbi, String instructionSet, String invokeWith,
long startTime) {
try {
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "Start proc: " +
app.processName);
checkTime(startTime, "startProcess: asking zygote to start proc");
final ProcessStartResult startResult;
if (hostingType.equals("webview_service")) {
startResult = startWebView(entryPoint,
app.processName, uid, uid, gids, runtimeFlags, mountExternal,
app.info.targetSdkVersion, seInfo, requiredAbi, instructionSet,
app.info.dataDir, null,
new String[] {PROC_START_SEQ_IDENT + app.startSeq});
} else {
startResult = Process.start(entryPoint,
app.processName, uid, uid, gids, runtimeFlags, mountExternal,
app.info.targetSdkVersion, seInfo, requiredAbi, instructionSet,
app.info.dataDir, invokeWith,
new String[] {PROC_START_SEQ_IDENT + app.startSeq});
}
checkTime(startTime, "startProcess: returned from zygote!");
return startResult;
} finally {
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
}
}
複製代碼
Process :start ()-->ZygoteProcess:start()-->startViaZygote()-->openZygoteSocketIfNeeded()
上面能夠看到調用了Process 的start --->ZygoteProcess的start-->startViaZygote-->openZygoteSocketIfNeeded建立zygote socket鏈接, 經過native 方法去執行Zygote的main()方法
@GuardedBy("mLock")
private ZygoteState openZygoteSocketIfNeeded(String abi) throws ZygoteStartFailedEx {
Preconditions.checkState(Thread.holdsLock(mLock), "ZygoteProcess lock not held");
if (primaryZygoteState == null || primaryZygoteState.isClosed()) {
try {
//========================
primaryZygoteState = ZygoteState.connect(mSocket);
} catch (IOException ioe) {
throw new ZygoteStartFailedEx("Error connecting to primary zygote", ioe);
}
maybeSetApiBlacklistExemptions(primaryZygoteState, false);
maybeSetHiddenApiAccessLogSampleRate(primaryZygoteState);
}
if (primaryZygoteState.matches(abi)) {
return primaryZygoteState;
}
// The primary zygote didn't match. Try the secondary. if (secondaryZygoteState == null || secondaryZygoteState.isClosed()) { try { secondaryZygoteState = ZygoteState.connect(mSecondarySocket); } catch (IOException ioe) { throw new ZygoteStartFailedEx("Error connecting to secondary zygote", ioe); } maybeSetApiBlacklistExemptions(secondaryZygoteState, false); maybeSetHiddenApiAccessLogSampleRate(secondaryZygoteState); } if (secondaryZygoteState.matches(abi)) { return secondaryZygoteState; } throw new ZygoteStartFailedEx("Unsupported zygote ABI: " + abi); } 複製代碼
ZygoteState:connect()-->zygote :main()-->zygoteServer:runSelectLoop()
zygote main方法被調用
public static void main(String argv[]) {
ZygoteServer zygoteServer = new ZygoteServer();
// Mark zygote start. This ensures that thread creation will throw
// an error.
ZygoteHooks.startZygoteNoThreadCreation();
// Zygote goes into its own process group.
try {
Os.setpgid(0, 0);
} catch (ErrnoException ex) {
throw new RuntimeException("Failed to setpgid(0,0)", ex);
}
final Runnable caller;
try {
// Report Zygote start time to tron unless it is a runtime restart
if (!"1".equals(SystemProperties.get("sys.boot_completed"))) {
MetricsLogger.histogram(null, "boot_zygote_init",
(int) SystemClock.elapsedRealtime());
}
String bootTimeTag = Process.is64Bit() ? "Zygote64Timing" : "Zygote32Timing";
TimingsTraceLog bootTimingsTraceLog = new TimingsTraceLog(bootTimeTag,
Trace.TRACE_TAG_DALVIK);
bootTimingsTraceLog.traceBegin("ZygoteInit");
RuntimeInit.enableDdms();
boolean startSystemServer = false;
String socketName = "zygote";
String abiList = null;
boolean enableLazyPreload = false;
for (int i = 1; i < argv.length; i++) {
if ("start-system-server".equals(argv[i])) {
startSystemServer = true;
} else if ("--enable-lazy-preload".equals(argv[i])) {
enableLazyPreload = true;
} else if (argv[i].startsWith(ABI_LIST_ARG)) {
abiList = argv[i].substring(ABI_LIST_ARG.length());
} else if (argv[i].startsWith(SOCKET_NAME_ARG)) {
socketName = argv[i].substring(SOCKET_NAME_ARG.length());
} else {
throw new RuntimeException("Unknown command line argument: " + argv[i]);
}
}
if (abiList == null) {
throw new RuntimeException("No ABI list supplied.");
}
//註冊socket
zygoteServer.registerServerSocketFromEnv(socketName);
// In some configurations, we avoid preloading resources and classes eagerly.
// In such cases, we will preload things prior to our first fork.
if (!enableLazyPreload) {
bootTimingsTraceLog.traceBegin("ZygotePreload");
EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_START,
SystemClock.uptimeMillis());
preload(bootTimingsTraceLog);
EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_END,
SystemClock.uptimeMillis());
bootTimingsTraceLog.traceEnd(); // ZygotePreload
} else {
Zygote.resetNicePriority();
}
// Do an initial gc to clean up after startup
bootTimingsTraceLog.traceBegin("PostZygoteInitGC");
gcAndFinalize();
bootTimingsTraceLog.traceEnd(); // PostZygoteInitGC
bootTimingsTraceLog.traceEnd(); // ZygoteInit
// Disable tracing so that forked processes do not inherit stale tracing tags from
// Zygote.
Trace.setTracingEnabled(false, 0);
Zygote.nativeSecurityInit();
// Zygote process unmounts root storage spaces.
Zygote.nativeUnmountStorageOnInit();
ZygoteHooks.stopZygoteNoThreadCreation();
//===============開啓systemservice
if (startSystemServer) {
Runnable r = forkSystemServer(abiList, socketName, zygoteServer);
// {@code r == null} in the parent (zygote) process, and {@code r != null} in the
// child (system_server) process.
if (r != null) {
r.run();
return;
}
}
Log.i(TAG, "Accepting command socket connections");
// The select loop returns early in the child process after a fork and
// loops forever in the zygote.
//socket 輪詢 去建立一個新的進程
caller = zygoteServer.runSelectLoop(abiList);
} catch (Throwable ex) {
Log.e(TAG, "System zygote died with exception", ex);
throw ex;
} finally {
zygoteServer.closeServerSocket();
}
// We're in the child process and have exited the select loop. Proceed to execute the // command. //====================執行ActivityThread的main方法 if (caller != null) { caller.run(); } } 複製代碼
ZygoteService---->runSelectLoop
Runnable runSelectLoop(String abiList) {
ArrayList<FileDescriptor> fds = new ArrayList<FileDescriptor>();
ArrayList<ZygoteConnection> peers = new ArrayList<ZygoteConnection>();
fds.add(mServerSocket.getFileDescriptor());
peers.add(null);
while (true) {
StructPollfd[] pollFds = new StructPollfd[fds.size()];
for (int i = 0; i < pollFds.length; ++i) {
pollFds[i] = new StructPollfd();
pollFds[i].fd = fds.get(i);
pollFds[i].events = (short) POLLIN;
}
try {
Os.poll(pollFds, -1);
} catch (ErrnoException ex) {
throw new RuntimeException("poll failed", ex);
}
for (int i = pollFds.length - 1; i >= 0; --i) {
if ((pollFds[i].revents & POLLIN) == 0) {
continue;
}
if (i == 0) {
ZygoteConnection newPeer = acceptCommandPeer(abiList);
peers.add(newPeer);
fds.add(newPeer.getFileDesciptor());
} else {
try {
ZygoteConnection connection = peers.get(i);
//======================
final Runnable command = connection.processOneCommand(this);
....................
} catch (Exception e) {
.................
}
}
}
}
}
}
複製代碼
ZygoteConnection:processOneCommand()--->handleChildProc()
Runnable processOneCommand(ZygoteServer zygoteServer) {
.....................
try {
if (pid == 0) {
// in child
zygoteServer.setForkChild();
zygoteServer.closeServerSocket();
IoUtils.closeQuietly(serverPipeFd);
serverPipeFd = null;
//============================這裏
return handleChildProc(parsedArgs, descriptors, childPipeFd,
parsedArgs.startChildZygote);
} else {
// In the parent. A pid < 0 indicates a failure and will be handled in
// handleParentProc.
IoUtils.closeQuietly(childPipeFd);
childPipeFd = null;
handleParentProc(pid, descriptors, serverPipeFd);
return null;
}
} finally {
IoUtils.closeQuietly(childPipeFd);
IoUtils.closeQuietly(serverPipeFd);
}
}
private Runnable handleChildProc(Arguments parsedArgs, FileDescriptor[] descriptors,
FileDescriptor pipeFd, boolean isZygote) {
.................................
// End of the postFork event.
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
if (parsedArgs.invokeWith != null) {
WrapperInit.execApplication(parsedArgs.invokeWith,
parsedArgs.niceName, parsedArgs.targetSdkVersion,
VMRuntime.getCurrentInstructionSet(),
pipeFd, parsedArgs.remainingArgs);
// Should not get here.
throw new IllegalStateException("WrapperInit.execApplication unexpectedly returned");
} else {
if (!isZygote) {
return ZygoteInit.zygoteInit(parsedArgs.targetSdkVersion, parsedArgs.remainingArgs,
null /* classLoader */);
} else {
return ZygoteInit.childZygoteInit(parsedArgs.targetSdkVersion,
parsedArgs.remainingArgs, null /* classLoader */);
}
}
}
複製代碼
ZtgoteInit: zygoteInit()
public static final Runnable zygoteInit(int targetSdkVersion, String[] argv, ClassLoader classLoader) {
if (RuntimeInit.DEBUG) {
Slog.d(RuntimeInit.TAG, "RuntimeInit: Starting application from zygote");
}
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "ZygoteInit");
RuntimeInit.redirectLogStreams();
RuntimeInit.commonInit();
//========native 初始化zygote
ZygoteInit.nativeZygoteInit();
//調用ActivityThread 的main方法
return RuntimeInit.applicationInit(targetSdkVersion, argv, classLoader);
}
複製代碼
RuntimeInit: applicationInit()
protected static Runnable applicationInit(int targetSdkVersion, String[] argv,
ClassLoader classLoader) {
..............................
return findStaticMain(args.startClass, args.startArgs, classLoader);
}
protected static Runnable findStaticMain(String className, String[] argv,
ClassLoader classLoader) {
Class<?> cl;
try {
cl = Class.forName(className, true, classLoader);
} catch (ClassNotFoundException ex) {
throw new RuntimeException(
"Missing class when invoking static main " + className,
ex);
}
Method m;
try {
//====================這裏經過反射 調用了 ActivityThread 的main方法
m = cl.getMethod("main", new Class[] { String[].class });
} catch (NoSuchMethodException ex) {
throw new RuntimeException(
"Missing static main on " + className, ex);
} catch (SecurityException ex) {
throw new RuntimeException(
"Problem getting static main on " + className, ex);
}
int modifiers = m.getModifiers();
if (! (Modifier.isStatic(modifiers) && Modifier.isPublic(modifiers))) {
throw new RuntimeException(
"Main method is not public and static on " + className);
}
return new MethodAndArgsCaller(m, argv);
}
複製代碼
至此 進程的初始化以及ActivityTnread 的調用就執行完畢
3.Application的建立
public static void main(String[] args) {
Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "ActivityThreadMain");
// CloseGuard defaults to true and can be quite spammy. We
// disable it here, but selectively enable it later (via
// StrictMode) on debug builds, but using DropBox, not logs.
CloseGuard.setEnabled(false);
Environment.initForCurrentUser();
// Set the reporter for event logging in libcore
EventLogger.setReporter(new EventLoggingReporter());
// Make sure TrustedCertificateStore looks in the right place for CA certificates
final File configDir = Environment.getUserConfigDirectory(UserHandle.myUserId());
TrustedCertificateStore.setDefaultUserDirectory(configDir);
Process.setArgV0("<pre-initialized>");
Looper.prepareMainLooper();
// Find the value for {@link #PROC_START_SEQ_IDENT} if provided on the command line.
// It will be in the format "seq=114"
long startSeq = 0;
if (args != null) {
for (int i = args.length - 1; i >= 0; --i) {
if (args[i] != null && args[i].startsWith(PROC_START_SEQ_IDENT)) {
startSeq = Long.parseLong(
args[i].substring(PROC_START_SEQ_IDENT.length()));
}
}
}
ActivityThread thread = new ActivityThread();
thread.attach(false, startSeq);
if (sMainThreadHandler == null) {
sMainThreadHandler = thread.getHandler();
}
if (false) {
Looper.myLooper().setMessageLogging(new
LogPrinter(Log.DEBUG, "ActivityThread"));
}
// End of event ActivityThreadMain.
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
Looper.loop();
throw new RuntimeException("Main thread loop unexpectedly exited");
}
複製代碼
經過查看 ActivityThread 的源碼,能夠找到 程序的啓動入口在main()方法裏,能夠看到啓動入口初始化了looper ,咱們的啓動邏輯在attach方法中
//只放黏貼了咱們關心的代碼
public static void main(String[] args) {
.........
Looper.prepareMainLooper();
ActivityThread thread = new ActivityThread();
//啓動邏輯在attach 中
thread.attach(false, startSeq);
if (sMainThreadHandler == null) {
sMainThreadHandler = thread.getHandler();
}
Looper.loop();
}
複製代碼
接下來再看attach 能夠找到mgr.attachApplication(mAppThread, startSeq); 這句代碼 調用了ActivityManagerService 裏的attachApplication方法,去獲取application的信息,最後會調用 ApplicationThread裏的 bindApplication 經過遠端進程去回調handleBindApplication(AppBindData data) --> app = data.info.makeApplication(data.restrictedBackupMode, null);--> mInstrumentation.callApplicationOnCreate(app);----》 app.onCreate();(這個就是咱們初始化信息的生命週期)
ActivityThread的main()-->attach()====> mgr.attachApplication(mAppThread, startSeq);
public static void main(String[] args) {
.......
//looper 初始化
Looper.prepareMainLooper();
// Find the value for {@link #PROC_START_SEQ_IDENT} if provided on the command line.
// It will be in the format "seq=114"
long startSeq = 0;
if (args != null) {
for (int i = args.length - 1; i >= 0; --i) {
if (args[i] != null && args[i].startsWith(PROC_START_SEQ_IDENT)) {
startSeq = Long.parseLong(
args[i].substring(PROC_START_SEQ_IDENT.length()));
}
}
}
//建立實例
ActivityThread thread = new ActivityThread();
thread.attach(false, startSeq);
if (sMainThreadHandler == null) {
sMainThreadHandler = thread.getHandler();
}
if (false) {
Looper.myLooper().setMessageLogging(new
LogPrinter(Log.DEBUG, "ActivityThread"));
}
// End of event ActivityThreadMain.
Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
Looper.loop();
throw new RuntimeException("Main thread loop unexpectedly exited");
}
private void attach(boolean system, long startSeq) {
sCurrentActivityThread = this;
mSystemThread = system;
if (!system) {
ViewRootImpl.addFirstDrawHandler(new Runnable() {
@Override
public void run() {
ensureJitEnabled();
}
});
android.ddm.DdmHandleAppName.setAppName("<pre-initialized>",
UserHandle.myUserId());
RuntimeInit.setApplicationObject(mAppThread.asBinder());
final IActivityManager mgr = ActivityManager.getService();
try {
//========================
mgr.attachApplication(mAppThread, startSeq);
} catch (RemoteException ex) {
throw ex.rethrowFromSystemServer();
}
// Watch for getting close
..............................
}}}
複製代碼
ActivityManagerService -->attachApplication--> ApplicationThread.bindApplication()-->attachApplicationLocked
void attachApplicationLocked(){
........................
if (app.isolatedEntryPoint != null) {
// This is an isolated process which should just call an entry point instead of
// being bound to an application.
thread.runIsolatedEntryPoint(app.isolatedEntryPoint, app.isolatedEntryPointArgs);
} else if (app.instr != null) {
thread.bindApplication(processName, appInfo, providers,
app.instr.mClass,
profilerInfo, app.instr.mArguments,
app.instr.mWatcher,
app.instr.mUiAutomationConnection, testMode,
mBinderTransactionTrackingEnabled, enableTrackAllocation,
isRestrictedBackupMode || !normalMode, app.persistent,
new Configuration(getGlobalConfiguration()), app.compat,
getCommonServicesLocked(app.isolated),
mCoreSettingsObserver.getCoreSettingsLocked(),
buildSerial, isAutofillCompatEnabled);
} else {
thread.bindApplication(processName, appInfo, providers, null, profilerInfo,
null, null, null, testMode,
mBinderTransactionTrackingEnabled, enableTrackAllocation,
isRestrictedBackupMode || !normalMode, app.persistent,
new Configuration(getGlobalConfiguration()), app.compat,
getCommonServicesLocked(app.isolated),
mCoreSettingsObserver.getCoreSettingsLocked(),
buildSerial, isAutofillCompatEnabled);
}
....................
}
複製代碼
ApplicationThread的bindApplication發送一條handler 信息 sendMessage(H.BIND_APPLICATION, data) 回調handleBindApplication 執行makeApplication方法裏 會調用mInstrumentation 的mActivityThread.mInstrumentation.newApplication(cl, appClass, appContext); 建立application 對象調用attach方法
private void handleBindApplication(AppBindData data) {
if ((data.appInfo.flags&ApplicationInfo.FLAG_LARGE_HEAP) != 0) {
dalvik.system.VMRuntime.getRuntime().clearGrowthLimit();
} else {
// Small heap, clamp to the current growth limit and let the heap release
// pages after the growth limit to the non growth limit capacity. b/18387825
dalvik.system.VMRuntime.getRuntime().clampGrowthLimit();
}
// Allow disk access during application and provider setup. This could
// block processing ordered broadcasts, but later processing would
// probably end up doing the same disk access.
Application app;
final StrictMode.ThreadPolicy savedPolicy = StrictMode.allowThreadDiskWrites();
final StrictMode.ThreadPolicy writesAllowedPolicy = StrictMode.getThreadPolicy();
try {
// If the app is being launched for full backup or restore, bring it up in
// ===================建立Application
app = data.info.makeApplication(data.restrictedBackupMode, null);
// Propagate autofill compat state
app.setAutofillCompatibilityEnabled(data.autofillCompatibilityEnabled);
mInitialApplication = app;
// don't bring up providers in restricted mode; they may depend on the // app's custom Application class
if (!data.restrictedBackupMode) {
if (!ArrayUtils.isEmpty(data.providers)) {
installContentProviders(app, data.providers);
// For process that contains content providers, we want to
// ensure that the JIT is enabled "at some point".
mH.sendEmptyMessageDelayed(H.ENABLE_JIT, 10*1000);
}
}
// Do this after providers, since instrumentation tests generally start their
// test thread at this point, and we don't want that racing. try { mInstrumentation.onCreate(data.instrumentationArgs); } catch (Exception e) { throw new RuntimeException( "Exception thrown in onCreate() of " + data.instrumentationName + ": " + e.toString(), e); } try { //回調Application的onCreate 方法 mInstrumentation.callApplicationOnCreate(app); } catch (Exception e) { if (!mInstrumentation.onException(app, e)) { throw new RuntimeException( "Unable to create application " + app.getClass().getName() + ": " + e.toString(), e); } } ......................... 複製代碼
到這裏Application的建立已經完成 向上迴路代碼 到ActivityManagerService 中的attachApplicationLocked 這個方法的後半部分也就是回調 ApplicationThread 的代碼以後 這裏會執行Activity的建立過程
5.Activity的建立
attachApplicationLocked ()
在中的attachApplicationLocked 中的後半段代碼中 StackSupervisor.attachApplicationLocked(app) 這個調用就是建立Activity
// See if the top visible activity is waiting to run in this process...
if (normalMode) {
try {
if (mStackSupervisor.attachApplicationLocked(app)) {
didSomething = true;
}
} catch (Exception e) {
Slog.wtf(TAG, "Exception thrown launching activities in " + app, e);
badApp = true;
}
}
複製代碼
ActivityStackSupervisor: attachApplicationLocked()--->realStartActivityLocked()
final boolean realStartActivityLocked(ActivityRecord r, ProcessRecord app,
boolean andResume, boolean checkConfig) throws RemoteException {
...
try {
...
final ClientTransaction clientTransaction = ClientTransaction.obtain(app.thread,
r.appToken);
//注意:LaunchActivityItem ResumeActivityItem
clientTransaction.addCallback(LaunchActivityItem .obtain(new Intent(r.intent),
System.identityHashCode(r), r.info,
// TODO: Have this take the merged configuration instead of separate global
// and override configs.
mergedConfiguration.getGlobalConfiguration(),
mergedConfiguration.getOverrideConfiguration(), r.compat,
r.launchedFromPackage, task.voiceInteractor, app.repProcState, r.icicle,
r.persistentState, results, newIntents, mService.isNextTransitionForward(),
profilerInfo));
// Set desired final state.
final ActivityLifecycleItem lifecycleItem;
if (andResume) {
lifecycleItem = ResumeActivityItem.obtain(mService.isNextTransitionForward());
} else {
lifecycleItem = PauseActivityItem.obtain();
}
clientTransaction.setLifecycleStateRequest(lifecycleItem);
// Schedule transaction.
// Activity啓動事務
mService.getLifecycleManager().scheduleTransaction(clientTransaction);
...
} catch (RemoteException e) {
if (r.launchFailed) {
// 第二次啓動失敗的異常處理
return false;
}
// 第一次啓動失敗，重試
r.launchFailed = true;
app.activities.remove(r);
throw e;
}
} finally {
endDeferResume();
}
...
return true;
}
複製代碼
#####mService.getLifecycleManager().scheduleTransaction(clientTransaction)--> TransactionExecutor.java---->execute(transaction) 最終會LaunchActivityItem 的 excute方法去調用ActivityThread 中的handleLaunchActivity
public void execute(ClientTransaction transaction) {
final IBinder token = transaction.getActivityToken();
log("Start resolving transaction for client: " + mTransactionHandler + ", token: " + token);
==================注意============
//執行Activity的建立
executeCallbacks(transaction);
//狀態回調 onStart onresume
executeLifecycleState(transaction);
mPendingActions.clear();
log("End resolving transaction");
}
public void executeCallbacks(ClientTransaction transaction) {
final List<ClientTransactionItem> callbacks = transaction.getCallbacks();
if (callbacks == null) {
// No callbacks to execute, return early.
return;
}
log("Resolving callbacks");
final IBinder token = transaction.getActivityToken();
ActivityClientRecord r = mTransactionHandler.getActivityClient(token);
// In case when post-execution state of the last callback matches the final state requested
// for the activity in this transaction, we won't do the last transition here and do it when // moving to final state instead (because it may contain additional parameters from server). final ActivityLifecycleItem finalStateRequest = transaction.getLifecycleStateRequest(); final int finalState = finalStateRequest != null ? finalStateRequest.getTargetState() : UNDEFINED; // Index of the last callback that requests some post-execution state. final int lastCallbackRequestingState = lastCallbackRequestingState(transaction); final int size = callbacks.size(); //循環以前添加的集合 去建立 Ativity 和執行onresume for (int i = 0; i < size; ++i) { final ClientTransactionItem item = callbacks.get(i); log("Resolving callback: " + item); final int postExecutionState = item.getPostExecutionState(); final int closestPreExecutionState = mHelper.getClosestPreExecutionState(r, item.getPostExecutionState()); if (closestPreExecutionState != UNDEFINED) { cycleToPath(r, closestPreExecutionState); } //這裏建立activity時 會去 LaunchActivityItem 去回調到 ActivityThread item.execute(mTransactionHandler, token, mPendingActions); item.postExecute(mTransactionHandler, token, mPendingActions); if (r == null) { // Launch activity request will create an activity record. r = mTransactionHandler.getActivityClient(token); } if (postExecutionState != UNDEFINED && r != null) { // Skip the very last transition and perform it by explicit state request instead. final boolean shouldExcludeLastTransition = i == lastCallbackRequestingState && finalState == postExecutionState; cycleToPath(r, postExecutionState, shouldExcludeLastTransition); } } } @Override public void execute(ClientTransactionHandler client, IBinder token, PendingTransactionActions pendingActions) { Trace.traceBegin(TRACE_TAG_ACTIVITY_MANAGER, "activityStart"); ActivityClientRecord r = new ActivityClientRecord(token, mIntent, mIdent, mInfo, mOverrideConfig, mCompatInfo, mReferrer, mVoiceInteractor, mState, mPersistentState, mPendingResults, mPendingNewIntents, mIsForward, mProfilerInfo, client);\ //=================ActivityThread 建立Activity client.handleLaunchActivity(r, pendingActions, null /* customIntent */); Trace.traceEnd(TRACE_TAG_ACTIVITY_MANAGER); } 複製代碼
ActivityThread: handleLaunchActivity--->performLaunchActivity
private Activity performLaunchActivity(ActivityClientRecord r, Intent customIntent) {
.........
//===================建立Activity========================
Activity activity = null;
try {
java.lang.ClassLoader cl = appContext.getClassLoader();
activity = mInstrumentation.newActivity(
cl, component.getClassName(), r.intent);
StrictMode.incrementExpectedActivityCount(activity.getClass());
r.intent.setExtrasClassLoader(cl);
r.intent.prepareToEnterProcess();
if (r.state != null) {
r.state.setClassLoader(cl);
}
} catch (Exception e) {
if (!mInstrumentation.onException(activity, e)) {
throw new RuntimeException(
"Unable to instantiate activity " + component
+ ": " + e.toString(), e);
}
}
try {
.............................
//=====================Activity的attach 方法============
activity.attach(appContext, this, getInstrumentation(), r.token,
r.ident, app, r.intent, r.activityInfo, title, r.parent,
r.embeddedID, r.lastNonConfigurationInstances, config,
r.referrer, r.voiceInteractor, window, r.configCallback);
if (customIntent != null) {
activity.mIntent = customIntent;
}
r.lastNonConfigurationInstances = null;
checkAndBlockForNetworkAccess();
activity.mStartedActivity = false;
int theme = r.activityInfo.getThemeResource();
if (theme != 0) {
activity.setTheme(theme);
}
//=====================Activity的生命週期回調============
activity.mCalled = false;
if (r.isPersistable()) {
mInstrumentation.callActivityOnCreate(activity, r.state, r.persistentState);
} else {
mInstrumentation.callActivityOnCreate(activity, r.state);
}
if (!activity.mCalled) {
throw new SuperNotCalledException(
"Activity " + r.intent.getComponent().toShortString() +
" did not call through to super.onCreate()");
}
r.activity = activity;
}
r.setState(ON_CREATE);
mActivities.put(r.token, r);
} catch (SuperNotCalledException e) {
throw e;
} catch (Exception e) {
if (!mInstrumentation.onException(activity, e)) {
throw new RuntimeException(
"Unable to start activity " + component
+ ": " + e.toString(), e);
}
}
return activity;
}
複製代碼
相關文章
- 1. Application建立流程分析
- 2. Application,Activity,Service的建立流程（1）
- 3. Application,Activity,Service的建立流程（2）
- 4. 從ActivityThread的建立窺探應用進程的啓動流程
- 5. Android framework——Activity的啓動和建立
- 6. Activity的Window建立過程
- 7. Android Window佈局建立流程分析
- 8. 理解Android進程建立流程（轉）
- 9. Android 組件 — Activity （建立與啓動）
- 10. 從App啓動理解ContentProvider的建立
- 更多相關文章...
- • TCP三次握手建立連接的過程 - TCP/IP教程
- • ionic 創建 APP - ionic 教程
- • 適用於PHP初學者的學習線路和建議
- • Git五分鐘教程
相關標籤/搜索
每日一句
-
每一个你不满意的现在，都有一个你没有努力的曾经。
歡迎關注本站公眾號,獲取更多信息
相關文章
- 1. Application建立流程分析
- 2. Application,Activity,Service的建立流程（1）
- 3. Application,Activity,Service的建立流程（2）
- 4. 從ActivityThread的建立窺探應用進程的啓動流程
- 5. Android framework——Activity的啓動和建立
- 6. Activity的Window建立過程
- 7. Android Window佈局建立流程分析
- 8. 理解Android進程建立流程（轉）
- 9. Android 組件 — Activity （建立與啓動）
- 10. 從App啓動理解ContentProvider的建立