android6.0源码分析之AMS服务源码分析
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android6.0源码分析之AMS服务源码分析
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activitymanagerservice服務(wù)源碼分析
1、ActivityManagerService概述
ActivityManagerService(以下簡稱AMS)作為Android中最核心的服務(wù)，主要負(fù)責(zé)系統(tǒng)的四大組件的啟動、切換、調(diào)度以及應(yīng)用進(jìn)程的管理和調(diào)度等工作。它類似于操作系統(tǒng)中的進(jìn)程管理和調(diào)度模塊類似，所以要想掌握android，AMS至關(guān)重要。AMS屬于service的一種，所以它也是由system_server進(jìn)行啟動以及管理。本文將以兩條不同的主線來分析AMS：第一條與其他服務(wù)一樣，分析system_server中AMS的調(diào)用軌跡；第二條將分析一個Activity的啟動過程,而Activity的啟動過程將在下一篇中進(jìn)行分析。?
先來看AMS的家族圖譜：?
?
圖中有一個ActivityManager類，由于ActivityManagerService是系統(tǒng)的核心服務(wù)，很多API不能開放給客戶端使用，所以在家族圖譜中增加了ActivityManager類，ActivityManager類通過調(diào)用ActivityManagerNative的getDefault函數(shù)來得到一個ActivityManagerProxy對象，通過它就可以實現(xiàn)ActivityManager與AMS的交互。
2、AMS的調(diào)用流程分析
AMS作為系統(tǒng)的核心服務(wù)，由system_server創(chuàng)建，system_server由Zygote進(jìn)程的startsystemserver觸發(fā)，此處以android6.0源碼為基礎(chǔ)，分析其run函數(shù)：
<code class="hljs r has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">private void run(){<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>//初始化native serversSystem.loadLibrary(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"android_servers"</span>);<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>//初始化system contextcreateSystemContext();//創(chuàng)建System service managermSystemServiceManager = new SystemServiceManager(mSystemContext);LocalServices.addService(SystemServiceManager.class,mSystemServiceManager);//start services<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>{startBootstrapservices();startCoreServices();startOtherServices();}catch(Throwable ex){throw ex;}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>Looper.loop();<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span> }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li></ul>2.1 createSystemContext()方法分析
<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">createSystemContext</span>(){<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//創(chuàng)建一個ActivityThread對象，它代表應(yīng)用進(jìn)程的主線程</span>ActivityThread activityThread = ActivityThread.systemMain();<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//獲取一個和應(yīng)用進(jìn)程一樣的android運(yùn)行上下文環(huán)境</span>mSystemContext = activityThread.getSystemContext();mSystemContext.setTheme(android.R.style.Theme_DeviceDefault_Light_DarkActionBar); }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li></ul>
首先分析ActivityThread的systemMain()方法，其代碼如下：
<code class="hljs r has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">public static ActivityThread systemMain(){<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>ActivityThread thread = new ActivityThread();thread.attach(true);<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> thread; }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>由代碼可知，其確實創(chuàng)建了一個ActivityThread對象，并調(diào)用其attach函數(shù)，記住，此處attach函數(shù)傳入的參數(shù)為true，而在分析Activity啟動的時候，它會為false，到時再對比分析。此處繼續(xù)分析attach函數(shù)：
<code class="hljs r has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">private void <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">attach</span>(boolean system) {<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (!system) {//此處為true，所以不會執(zhí)行此處代碼<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>android.ddm.DdmHandleAppName.setAppName(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"<pre-initialized>"</span>,UserHandle.myUserId());RuntimeInit.setApplicationObject(mAppThread.asBinder());final IActivityManager mgr = ActivityManagerNative.getDefault();<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {mgr.attachApplication(mAppThread);} catch (RemoteException ex) {// Ignore}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {//執(zhí)行此分支android.ddm.DdmHandleAppName.setAppName(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"system_process"</span>,UserHandle.myUserId());<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {mInstrumentation = new Instrumentation();//由ContextImol創(chuàng)建Context對象ContextImpl context = ContextImpl.createAppContext(this, getSystemContext().mPackageInfo);mInitialApplication = context.mPackageInfo.makeApplication(true, null);mInitialApplication.onCreate();} catch (Exception e) {}}//添加Dropbox logging 到libcoreDropBox.setReporter(new DropBoxReporter());ViewRootImpl.addConfigCallback(new ComponentCallbacks2(){<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>});<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span> }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li></ul>由于此處為系統(tǒng)服務(wù)，所以會執(zhí)行else分支的代碼，創(chuàng)建一個context對象，并且會根據(jù)Package信息來初始化一個Application對象。接著分析ActivityThread的getSystemContext()方法：
<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> ContextImpl <span class="hljs-title" style="box-sizing: border-box;">getSystemContext</span>(){Synchronized(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>){<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(mSystemContext == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>){mSystemContext = ContextImpl.createSystemContext(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>);}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> mSystemContext;} }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li></ul> 顯然，如果systemMain方法中創(chuàng)建Context成功，則返回，否則新建Context對象，綜上，createSystemContext()方法主要功能就是，創(chuàng)建一個ActivityThread對象和一個ContextImpl對象，而這兩個對象即組成了android運(yùn)行環(huán)境。?
時序圖如下：?
2.2 startBootstrapServices()方法分析
先看核心代碼：
<code class="hljs r has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">private void startBootStrapServices(){//啟動Installer服務(wù)Installer installer = mSystemServiceManager.startService(Installer.class);//啟動ActivityManagerService服務(wù)mActivityManagerService = mSystemServiceManager.startService(ActivityManagerService.Lifecycle.class).getService();//啟動PowerManagerService服務(wù)mPowerManagerService = mSystemServiceManager.startService(PowerManagerService.class);<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>//初始化屬性緩存AttributeCache.init(mSystemContext);mActivityManagerService.setSystemProcess();startSensorService(); }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul>代碼中，會將一系列的服務(wù)添加到servicemanager管理，主要包括Installer,AMS,PMS等系統(tǒng)服務(wù)，并初始化屬性緩存，最后會調(diào)用AMS的setSystemProcess()方法將sytem_server進(jìn)程并入AMS的管理范圍，繼續(xù)分析setSystemProcess()方法：
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setSystemProcess</span>(){<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>{<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//添加ActvityManagerService等服務(wù)到ServiceManager</span>ServiceManager.addService(Context.ACTIVITY_SERVICE,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);...ServiceManager.addService(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"meminfo"</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> MemBinder(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>));ServiceManager.addService(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"gfxinfo"</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> GraohicsBinder(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>));ServiceManager.addService(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"dbinfo"</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> DbBinder(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>));...<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//從packagemanagerservice中獲取ApplicationInfo信息</span>ApplicationInfo info = mContext.getPackageManager().getApplicationInfo(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"android"</span>,STOCK_PM_FLAGS);<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//根據(jù)info初始化android運(yùn)行環(huán)境，即ActivityThread以及ContextImpl對象</span>mSystemThread.installSystemApplicationInfo(info,getClass().getClassLoader());<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">synchronized</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>){<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//創(chuàng)建新的進(jìn)程</span>ProcessRecord app = newProcessRecordLocked(info,info.processName,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>);app.persistent = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;app.pid = MY_PID;app.maxAdj = ProcessList.SYSTEM_ADJ;<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//綁定主線程</span>app.makeActive(mSystemThread.getApplicationThread(),mProcessStats);<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">synchronized</span>(mPidsSelfLocked){mPidsSelfLocked.put(app.pid,app);}<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//更新進(jìn)程管理</span>updateLruProcessLocked(app,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>);updateOomAdjLocked();}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span>(PackageManager.NameNotFoundException ex){<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throw</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> RuntimeException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"unable to find android system package"</span>,ex);}} }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li></ul>首先分析installSystemApplicationInfo方法，它依次調(diào)用ActivityThread->ContextImpl->LoadedApk等的installSystemApplicationInfo方法，LoadedApk中的代碼如下：
<code class="hljs nginx has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">void</span> installSystemApplicationInfo(ApplicationInfo <span class="hljs-built_in" style="color: rgb(155, 133, 157); box-sizing: border-box;">info</span>,ClassLoader classLoader){<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">assert</span> <span class="hljs-built_in" style="color: rgb(155, 133, 157); box-sizing: border-box;">info</span>.packageName.equals(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"android"</span>);<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mApplicationInfo</span> = <span class="hljs-built_in" style="color: rgb(155, 133, 157); box-sizing: border-box;">info</span>;<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">mClassLoader</span> = classLoader; }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul> 顯然，是根據(jù)先前從Package里面獲取的ApplicationInfo對系統(tǒng)的應(yīng)用信息進(jìn)行初始化，主要包括ApplicationInfo以及ClassLoader對象。?
接著，分析創(chuàng)建新進(jìn)程的方法newProcessRecordLocked():
它首先創(chuàng)建一個進(jìn)程對象ProcessRecord，并將其加入到自定義的ProcessMap類型的容器里，最后返回。?
最后，分析更新進(jìn)程管理updateLruProcessLocked()方法：
此段代碼就是進(jìn)程LRU進(jìn)程調(diào)度，具體參考注釋。?
小結(jié)：startBootStrapServices()主要是進(jìn)行一系列的服務(wù)的注冊，并且初始化進(jìn)程信息，并將其加入到Lru進(jìn)程表進(jìn)行調(diào)度，同時也將System_server進(jìn)程納入AMS的管理。
2.3 startOtherServices()方法分析
與ActivityManagerService有關(guān)的核心代碼如下:
<code class="hljs r has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">private void startOtherServices(){final Context context = mSystemContext;//啟動一系列的服務(wù)，CameraService,Account Manager,Telephony registry等<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>//啟動settingProvider,它提供配置信息mActivityManagerService.installSystemProviders();<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>//初始化窗口管理服務(wù)wm = WindowManagerService.main(content,inputManager,mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL,!mFirstBoot,mOnlyCore);ServiceManager.addService(Context.WINDOW_SERVICE,wm);ServiceManager.addService(Context.INPUT_SERVICE,inputManager);//在內(nèi)部保存窗口管理服務(wù)WMSmActivityManagerService.setWindowManager(wm);<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>//和WMS交互，彈出“啟動進(jìn)度”對話框mActivityManagerNative.getDefault().showBootMessage(context.getResources().getText(com.android.internal.R.String.android_upgrading_starting_apps));<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>mActivityManagerService.systemReady(new Runnable(){@Overridepublic void run(){<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>//標(biāo)記服務(wù)(services)準(zhǔn)備完畢mSystemServiceManager.startBootPhase(SystemService.PHASE_ACTIVITY_MANAGER_READY);<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>{//啟動桌面startSystemUi(context);}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>}}); }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li></ul>首先，分析installSystemProviders()方法：
<code class="hljs r has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">public final void installSystemProviders(){List<ProviderInfo> providers;synchronized(this){ProcessRecord app = mProcessNames.get(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"system"</span>,Process.SYSTEM_UID);//根據(jù)進(jìn)程名以及進(jìn)程uid向PKMS查詢滿足要求的ProviderInfoproviders = generateApplicationProvidersLocked(app);<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span>}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(providers != null){mSystemThread.installSystemProviders(providers);}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">...</span> }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li></ul>從進(jìn)程Map表里，根據(jù)進(jìn)程名字system來獲取進(jìn)程，并根據(jù)進(jìn)程app來獲取其應(yīng)用信息中的providers，接著調(diào)用ActivityThread的installSystemProviders()方法來進(jìn)行配置信息解析。
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//ActivityThread.java</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">installSystemProviders</span>(List<ProviderInfo> providers){<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(providers != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>){installContentProviders(mInitialApplication,providers);} }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>跟蹤installContentProviders()方法：
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">installContentProviders</span>(Context context,List<ProviderInfo> providers){<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> ArrayList<IActivityManager.ContentProviderHolder> results = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> ArrayList<IActivityManager.ContentProviderHolder>();<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span>(ProviderInfo cpi:providers){<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//通過調(diào)用istallProvider函數(shù)獲得一個ContentProviderHolder對象</span>IActivityManager.ContentProviderHolder cph = installProvider(context,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>,cpi,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(cph != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>){cph.noReleaseNeeded = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//保存獲得的cph對象</span>results.add(cph);}}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>{<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//調(diào)用AMS的publishContentProvider注冊此前的results里的cph。</span>ActivityManagerNative.getDefault().publishContentProviders(getApplicationThread(),results);}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span>(RemoteException ex){} }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul> 從代碼可以看出，首先調(diào)用installProvider函數(shù)獲得一個ContentProviderHolder對象，并將其保存在容器中，最后在調(diào)用AMS的publishContentProvider來注冊容器中的所有ContentProviderHolder對象。至此，一個SettingProvider對象就正式的注冊到了AMS.?
繼續(xù)分析startOtherServices()方法中mActivityManagerService.systemReady(final Runnable goingcallback)方法:
首先，檢查系統(tǒng)是否是更新，并發(fā)送PRE_BOOT_COMPLETE廣播，并將mSystemReady置為true。接著調(diào)用函數(shù)傳入的回調(diào)goingCallback的run方法，在run方法中主要功能是啟動SystemUIService服務(wù)，其代碼如下：
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> startSystemUi(Context context){Intent intent = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Intent();intent.setComponent(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> ComponentName(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"com.android.systemui"</span>,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"com.android.systemui.SystemUIService"</span>));context.startServiceAsUser(intent,UserHandle.OWNER); }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul> 它主要是啟動了一個SystemUIService服務(wù)，此服務(wù)由SystemUi.apk提供，實現(xiàn)了狀態(tài)欄。執(zhí)行了回調(diào)之后，systemReady方法接著，從PKMS中找出所有persistent屬性為1的ApplicationInfo，并將其所在的進(jìn)程逐個啟動，最后再調(diào)用startHomeActivityLocked來啟動Home界面，?
總結(jié)：到此時，從system_server進(jìn)程開始，著重分析了ActivityManagerService服務(wù)的啟動過程，至此，整個系統(tǒng)準(zhǔn)備完畢，此處不詳細(xì)分析Home的啟動過程，它的啟動將會在Activity的啟動過程中進(jìn)行詳細(xì)的分析，而Home啟動成功后，AMS會發(fā)送ACTION_BOOT_COMPLETED廣播。AMS的啟動流程很復(fù)雜，下面給出整體的時序圖：?
原文地址：http://blog.csdn.net/yangzhihuiguming/article/details/51700157
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