Activity 的啟動流程原始碼剖析（三）

android 27

v4 27.1.1

我都是粘的裡面比較關鍵的原始碼，還希望配合原始碼閱讀

這是本篇的大概流程，先熟悉一下吧

流程

public final void schedulelaunchactivity(intent intent, ibinder token, int ident,

activityinfo info, configuration curconfig, configuration overrideconfig,
compatibilityinfo compatinfo, string referrer, ivoiceinteractor voiceinteractor,
int procstate, bundle state, persistablebundle persistentstate,
listpendingresults, listpendingnewintents,
boolean notresumed, boolean isforward, profilerinfo profilerinfo) 

private void sendmessage(int what, object obj, int arg1, int arg2, boolean async) 

mh.sendmessage(msg);
}

我們接下來找到 h 處理 launch_activity 的**

case launch_activity:  break;

private void handlelaunchactivity(activityclientrecord r, intent customintent, string reason) 

}} else  catch (remoteexception ex) }}

我們先看 performlaunchactivity()、然後在看 handleresumeactivity()

private activity performlaunchactivity(activityclientrecord r, intent customintent) 

// 建立contextimpl
activity activity = null;
try 
} catch (exception e) 
}try 
if (debug_configuration) slog.v(tag, "launching activity "
+ r.activityinfo.name + " with config " + config);
window window = null;
if (r.mpendingremovewindow != null && r.mpreservewindow) 
//activity attach 裡面**可以自己看一看，各種屬性設定 phonewindow 的宣告，各種事件的監聽都在裡面
r.embeddedid, r.lastnonconfigurationinstances, config,
r.referrer, r.voiceinteractor, window, r.configcallback);
if (customintent != null) 
r.lastnonconfigurationinstances = null;
checkandblockfornetworkaccess();
activity.mstartedactivity = false;
int theme = r.activityinfo.getthemeresource();
if (theme != 0) 
activity.mcalled = false;
//建立 activity
if (r.ispersistable())  else 
if (!activity.mcalled) 
r.activity = activity;
r.stopped = true;
if (!r.activity.mfinished) 
//呼叫 activity 的 onrestoreinstancestate
if (!r.activity.mfinished) 
} else if (r.state != null) 
}//呼叫 onpostcreate
if (!r.activity.mfinished)  else 
if (!activity.mcalled) }}
r.paused = true;
mactivities.put(r.token, r);
} catch (supernotcalledexception e)  catch (exception e) 
return activity;
}

我們再看一下 handleresumeactivity() 方法

final void handleresumeactivity(ibinder token,

boolean clearhide, boolean isforward, boolean reallyresume, int seq, string reason) 
unschedulegcidler();
msomeactivitieschanged = true;
// 裡面呼叫了 activity 的 onresume()
r = performresumeactivity(token, clearhide, reason);
}

這一篇章我沒有把**貼太全，粘太全的**太亂了，我用中文注釋的地方希望都點進去看看。

最後再放一張完整的圖

activity 啟動流程.jpg

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