Android 子Activity組件在進程內的啟動過程 && 子Activity組件在新進程中的啟動過程

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1、子Activity組件在進程內的啟動過程

       在Android Activity組件的啟動過程http://blog.csdn.net/jltxgcy/article/details/35984557一文中，我們已經詳細分析了Activity的啟動過程，對於子Activity組件在進程內的啟動過程，我們只分析它們之間的不同。

       主要是2處，1是不需要建立新的任務棧，2是不需要建立新進程和子線程。

       第1點，體現在如下代碼上：

       ～/Android/frameworks/base/services/java/com/android/server/am

       ----ActivityStack.java

public class ActivityStack {......final int startActivityUncheckedLocked(ActivityRecord r,   ActivityRecord sourceRecord, Uri[] grantedUriPermissions,   int grantedMode, boolean onlyIfNeeded, boolean doResume) {final Intent intent = r.intent;final int callingUid = r.launchedFromUid;int launchFlags = intent.getFlags();......if (sourceRecord == null) {   ......} else if (sourceRecord.launchMode == ActivityInfo.LAUNCH_SINGLE_INSTANCE) {   ......} else if (r.launchMode == ActivityInfo.LAUNCH_SINGLE_INSTANCE   ......}if (r.resultTo != null && (launchFlags&Intent.FLAG_ACTIVITY_NEW_TASK) != 0) {   ......}boolean addingToTask = false;........boolean newTask = false;// Should this be considered a new task?if (r.resultTo == null && !addingToTask   && (launchFlags&Intent.FLAG_ACTIVITY_NEW_TASK) != 0) {......} else if (sourceRecord != null) {......// An existing activity is starting this new activity, so we want// to keep the new one in the same task as the one that is starting// it.r.task = sourceRecord.task;......} else {   ......}......startActivityLocked(r, newTask, doResume);return START_SUCCESS;}......}

        第2點，體現在如下代碼上，此時已經有了子Activity進程和它的子線程了。

 private final 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);                .....                if (app != null && app.thread != null) {            try {                realStartActivityLocked(r, app, andResume, checkConfig);                return;            } catch (RemoteException e) {                .....            }            .....        }        ......}

2、子Activity組件在新進程中的啟動過程

      和Android Activity組件的啟動過程http://blog.csdn.net/jltxgcy/article/details/35984557一文中，主要有一個區別，不需要建立新的任務棧。代碼如上面所示。還需要建立新進程和子線程。