亚洲免费在线-亚洲免费在线播放-亚洲免费在线观看-亚洲免费在线观看视频-亚洲免费在线看-亚洲免费在线视频

Talking about Android Process

系統 2021 0

[First written by Steve Guo, please keep the mark if forwarding.]

In this topic you will learn some information about Android process management. First let’s take a look at the launched processes during Android booting.

USER PID PPID VSIZE RSS WCHAN PC NAME

root 1 0 264 176 c00acc6c 0000c36c S /init

root 28 1 724 308 c0051354 afe0c4cc S /system/bin/sh

system 30 1 796 248 c026516c afe0b74c S /system/bin/servicemanager

root 31 1 1824 316 ffffffff afe0b50c S /system/bin/mountd

root 32 1 652 248 c02976e0 afe0c0bc S /system/bin/debuggerd

radio 33 1 5344 664 ffffffff afe0bdbc S /system/bin/rild

root 34 1 71028 18828 c00ad308 afe0b874 S zygote

media 37 1 16812 3456 ffffffff afe0b74c S /system/bin/mediaserver

root 39 1 788 288 c02f9ae4 afe0b50c S /system/bin/installd

system 86 34 187756 21836 ffffffff afe0b74c S system_server

radio 118 34 103476 13896 ffffffff afe0c824 S com.android.phone

app_4 124 34 117848 19248 ffffffff afe0c824 S android.process.acore

app_5 139 34 98672 11516 ffffffff afe0c824 S com.android.mms

app_3 151 34 92096 10976 ffffffff afe0c824 S com.android.alarmclock

app_6 161 34 94436 12616 ffffffff afe0c824 S com.android.calendar

app_9 173 34 93248 11728 ffffffff afe0c824 S android.process.media

app_15 182 34 91848 9764 ffffffff afe0c824 S com.android.voicedialer

app_16 190 34 94524 10812 ffffffff afe0c824 S android.process.im

They can be divided into three kinds.

Root Process

init is the first process after kernel booting. The major task it performs:

l Parser and execute init.rc and init.%hardware%.rc

l Automatically generate device node under /dev

l Start log and property service

l Monitor for device, property set and child process exit events

Native Application Process

According to init.rc, init will fork the following native application process.

console : star a shell.

servicemanager : start binder IPC service manager.

mountd : mount all fs defined in /system/etc/mountd.conf if started, receive commands through local socket to mount any fs.

debuggerd : start debug system.

rild : start radio interface layer daemon.

zygote : start Android Java VM Runtime and start system server. It’s the most important process.

mediaserver : start AudioFlinger, MediaPlayerService and CameraService.

installd : start install package daemon.

JAVA Application Process

Every JAVA application process is forked from zygote process. system_server is a special JAVA process, which is directly forked from zygote.. Other JAVA process is created from ActivityManagerService(run in system_server process) like this.

int pid = Process.start("android.app.ActivityThread",

mSimpleProcessManagement ? app.processName : null, uid, uid,

gids, ((app.info.flags&ApplicationInfo.FLAG_DEBUGGABLE) != 0), null);

While Process.java use UNIX domain socket to communicate with zygote. So the overall picture is shown as following.

clip_image002

System Server

It’s the first JAVA application launched by zygote. It starts the core Android services, e.g. ActivityManager, WindowManager, PackageManager etc. It’s the Android core engine.

Persistent Application

During booting, ActivityManagerService.systemReady will start all persistent applications.

List apps = ActivityThread.getPackageManager().

getPersistentApplications(PackageManager.GET_SHARED_LIBRARY_FILES);

if (apps != null) {

int N = apps.size();

int i;

for (i=0; i<N; i++) {

ApplicationInfo info

= (ApplicationInfo)apps.get(i);

if (info != null &&

!info.packageName.equals("android")) {

addAppLocked(info);

}

}

}

Currently only Phone application is registered as a persistent app in AndroidManifest.xml like this.

<application android:name="PhoneApp"

android:persistent="true"

android:label="@string/dialerIconLabel"

android:icon="@drawable/ic_launcher_phone">

So during booting, only phone application is automatically launched. It’s the “com.android.phone” process.

The First Activity

The first activity is launched by senting Intent.CATEGORY_HOME intent from ActivityManagerService.

Intent intent = new Intent(

mTopAction,

mTopData != null ? Uri.parse(mTopData) : null);

intent.setComponent(mTopComponent);

if (mFactoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL) {

intent.addCategory( Intent.CATEGORY_HOME );

}

ActivityInfo aInfo =

intent.resolveActivityInfo(mContext.getPackageManager(),

PackageManager.GET_SHARED_LIBRARY_FILES);

if (aInfo != null) {

intent.setComponent(new ComponentName(

aInfo.applicationInfo.packageName, aInfo.name));

// Don't do this if the home app is currently being

// instrumented.

ProcessRecord app = getProcessRecordLocked(aInfo.processName,

aInfo.applicationInfo.uid);

if (app == null || app.instrumentationClass == null) {

intent.setFlags(intent.getFlags() | Intent.FLAG_ACTIVITY_NEW_TASK);

startActivityLocked(null, intent, null, null, 0, aInfo,

null, null, 0, 0, 0, false);

}

}

It’s the “android.process.acore” process. (The process name is defined in AndroidManifest.xml)

Auto-launched Application After Booting

When activity idle is detected in ActivityManagerService, it will broadcast ACTION_BOOT_COMPLETED intent at the first time.

if (mFactoryTest != SystemServer.FACTORY_TEST_LOW_LEVEL) {

// Tell anyone interested that we are done booting!

synchronized (this) {

broadcastIntentLocked(null, null,

new Intent( Intent.ACTION_BOOT_COMPLETED , null),

null, null, 0, null, null,

android.Manifest.permission.RECEIVE_BOOT_COMPLETED,

false, false, MY_PID, Process.SYSTEM_UID);

}

}

Currently, MMS, AlarmClock, Calendar, MediaProvider, VoiceDialer and IM have registered as a receiver for ACTION_BOOT_COMPLETED intent in their AndroidManifest.xml. So they will be automatically launched. (This explains the remained JAVA process.)

Email also registers as a receiver for ACTION_BOOT_COMPLETED intent in its AndroidManifest.xml, but it defines android:enable=”false”. So it won’t be launched.

<receiver android:name=".service.BootReceiver"

android:enabled="false"

>

<intent-filter>

<action android:name="android.intent.action.BOOT_COMPLETED" />

</intent-filter>

<intent-filter>

<action android:name="android.intent.action.DEVICE_STORAGE_LOW" />

</intent-filter>

<intent-filter>

<action android:name="android.intent.action.DEVICE_STORAGE_OK" />

</intent-filter>

</receiver>

DownloadProvider also registers as a receiver for ACTION_BOOT_COMPLETED intent in its AndroidManifest.xml, but it defines android:exported=”false”. So it won’t be launched.

<receiver android:name=".DownloadReceiver" android:exported="false" >

<intent-filter>

<action android:name="android.intent.action.BOOT_COMPLETED" />

<action android:name="android.net.conn.CONNECTIVITY_CHANGE" />

</intent-filter>

</receiver>

Behind the JAVA process

system_server is a special case. It calls ActivityThread.java’s systemMain static function, which creates an instance of ActivityThread. ActivityThread then creates an instance of ApplicationThread, Application and ApplicationContext.

Every other JAVA process works in a different way. It’s controlled by system_server while forked by zygote. When any JAVA process other than system_server is forked from zygote, it automatically calls ActivityThread.java’s main static function(See Process.java and the following code snippet).

try {

ZygoteInit.invokeStaticMain(cloader, className, mainArgs);

} catch (RuntimeException ex) {

logAndPrintError (newStderr, "Error starting. ", ex);

}

The ActivityThread.java’s main function creates an instance of ActivityThread. ActivityThread then creates an instance of ApplicationThread. The ApplicationThread will work as an IBinder object to interact with ActivityManagerService in system_server. The new process does nothting at this time other than waiting IPC call from system_server. The Application and ApplicationContext object won’t be created at this time. Actually it’s deferred to when the process really works, eg. start an activity, receive intent or start a service.

For example, when start an activity, ActivityManagerService know which process the to-be-launched activity should run in, so it will RPC call ApplicationThread’s scheduleLaunchActivity to launch a new activity in that process. ApplicationThread then post a message to let ActivityThread know it needs to start an activity. ActivityThread then creates Application and ApplicationContext object. After that, it calls Instrumentation, then Instrumentation finally calls JAVA dalvik VM to really create an activity JAVA object.

Talking about Android Process


更多文章、技術交流、商務合作、聯系博主

微信掃碼或搜索:z360901061

微信掃一掃加我為好友

QQ號聯系: 360901061

您的支持是博主寫作最大的動力,如果您喜歡我的文章,感覺我的文章對您有幫助,請用微信掃描下面二維碼支持博主2元、5元、10元、20元等您想捐的金額吧,狠狠點擊下面給點支持吧,站長非常感激您!手機微信長按不能支付解決辦法:請將微信支付二維碼保存到相冊,切換到微信,然后點擊微信右上角掃一掃功能,選擇支付二維碼完成支付。

【本文對您有幫助就好】

您的支持是博主寫作最大的動力,如果您喜歡我的文章,感覺我的文章對您有幫助,請用微信掃描上面二維碼支持博主2元、5元、10元、自定義金額等您想捐的金額吧,站長會非常 感謝您的哦!!!

發表我的評論
最新評論 總共0條評論
主站蜘蛛池模板: 久青草网站| va亚洲va日韩不卡在线观看 | 337p亚洲精品色噜噜狠狠 | 女人与女zzzoooxxxx | 香蕉视频一区二区三区 | 精品国产96亚洲一区二区三区 | 老司机午夜免费影院 | 免费特黄一级欧美大片在线看 | 亚洲日本人成网站在线观看 | 五月天天爱| 成人亚洲视频在线观看 | 国产在线看不卡一区二区 | 亚洲第一免费视频 | 咪咪色网 | 色播播影院 | 国产www视频| 免费费看的欧亚很色大片 | 欧美成人免费tv在线播放 | 亚洲综合网在线观看 | 一区二区三区四区在线 | 五月激情综合 | 国产一区二区三区高清视频 | 激情在线视频 | 欧美成人亚洲欧美成人 | 四虎在线视频免费观看 | 99re这里只有精品在线观看 | 久久久窝窝午夜精品 | 九月丁香婷婷亚洲综合色 | 欧美日韩国产综合一区二区三区 | 成人一区专区在线观看 | 国产精品视频免费在线观看 | 日本精品一区二区三本中文 | 亚洲欧美一区二区三区 | 不卡一二区 | 亚洲最大黄色网址 | 中文成人在线 | 国产精品成人va | 北条麻妃手机在线观看 | 国产网红在线视频 | 午夜欧美精品久久久久久久 | 成年女人午夜毛片免费看 |