谈谈Activity如何启动的

调用栈如下

ActivityManagerService.java

????????????? public void systemReady(final Runnable goingCallback) 传入goingCallback = null，

ActivityStack.java

??????????????? final boolean resumeTopActivityLocked(ActivityRecord prev) 传入 null

???????????????????????

?Process.java
? 
    public static final ProcessStartResult start(final String processClass,                                  final String niceName,                                  int uid, int gid, int[] gids,                                  int debugFlags, int targetSdkVersion,                                  String[] zygoteArgs) {        try {            return startViaZygote(processClass, niceName, uid, gid, gids,                    debugFlags, targetSdkVersion, zygoteArgs);        } catch (ZygoteStartFailedEx ex) {            Log.e(LOG_TAG,                    "Starting VM process through Zygote failed");            throw new RuntimeException(                    "Starting VM process through Zygote failed", ex);        }    }
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