LifecycleActivity记为A，LifecycleActivity2记为B
一, Standard
略．
二, SingleTop
打开App，启动第一个Activity(A1)，看到taskId == 2215
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2215
D/PRETTY_LOGGER: │ numActivities == 1
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity启动A2
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2215
D/PRETTY_LOGGER: │ numActivities == 2
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity启动B(singleTop)
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2215
D/PRETTY_LOGGER: │ numActivities == 3
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity2
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity再次启动B，B没有创新新实例，而是回调了onNewIntent方法
D/PRETTY_LOGGER: │ Instrumentation.callActivityOnNewIntent (Instrumentation.java:1215)
D/PRETTY_LOGGER: │ LifecycleActivity2.onNewIntent (LifecycleActivity2.kt:48)在B中，启动A，记为A3
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2215
D/PRETTY_LOGGER: │ numActivities == 4
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity在A3中，启动B，实例数增加１，说明不再顶部的B没有得到复用．
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2215
D/PRETTY_LOGGER: │ numActivities == 5
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity2
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity总结：singleTop，是栈内复用．
如果某activity为singleTop，
如果它位于栈顶，则回调onNewIntent()，而不新建实例；
如果不位于栈顶，则新建Activity．
三, SingleTask
打开App，启动第一个Activity(A1)，看到taskId == 2212
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2212
D/PRETTY_LOGGER: │ numActivities == 1
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity在A1中，启动第二个Activity(A2) ，看到taskId不变，activity实例数为２
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2212
D/PRETTY_LOGGER: │ numActivities == 2
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity在A2中，启动第三个Activity(B)，看到taskId仍不变．activity实例数为３
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2212
D/PRETTY_LOGGER: │ numActivities == 3
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity2
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity在B中，尝试启动B，看到B回调了onNewIntent方法
D/PRETTY_LOGGER: │ Instrumentation.callActivityOnNewIntent (Instrumentation.java:1215)
D/PRETTY_LOGGER: │ LifecycleActivity2.onNewIntent (LifecycleActivity2.kt:48)在B中，启动A，记为A3看到taskId仍不变，activity实例数增加１
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2212
D/PRETTY_LOGGER: │ numActivities == 4
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity在A3中启动B，此时A3出栈，B出现在栈顶．说明B(singleTask)在栈内复用了，栈内B之上的Activity都出栈．
然后，后续aciivity依次出栈．
总结：singleTask，栈内复用．
如果某Activity为singleTask
如果它位于栈顶，则不创建新实例，它在栈顶被复用；
如果位于栈中，则其上部所有Activity都出栈，该Activity置于栈顶，此为栈内复用．
四, SingleInstance
打开App，启动第一个Activity(A1)，看到taskId == 2208
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2208
D/PRETTY_LOGGER: │ numActivities == 1
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity在A1中，启动第二个Activity(A2) ，看到taskId不变，仍为2208
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2208
D/PRETTY_LOGGER: │ numActivities == 2
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity在A2中，启动第三个Activity(B)，看到taskId == 2209，已经发生变化
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2209
D/PRETTY_LOGGER: │ numActivities == 1
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity2
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity2我们在B中，再次启动B，看到B回调了onNewIntent方法，而且numActivities仍为1，说明没有创建新实例．
D/PRETTY_LOGGER: │ Instrumentation.callActivityOnNewIntent (Instrumentation.java:1215)
D/PRETTY_LOGGER: │ LifecycleActivity2.onNewIntent (LifecycleActivity2.kt:48)然后，在B中，启动A，看到回到了任务栈A中，activity的实例数增加1，此时的Activity数表示taskId为2208的activity数．
D/PRETTY_LOGGER: │ taskCount == 1
D/PRETTY_LOGGER: │ taskId == 2208
D/PRETTY_LOGGER: │ numActivities == 3
D/PRETTY_LOGGER: │ topActivity == .activity.LifecycleActivity
D/PRETTY_LOGGER: │ baseActivity == .activity.LifecycleActivity然后，点击返回按钮．发现，taskId(2208)的activity依次出栈，最后task(2209)的activity出栈．（图略）
总结：singleInstance，创建新的任务栈，而且该Activity独占这个任务栈．