Task是指将相关的Activity组合到一起,以Activity Stack的方式进行管理。从用户体验上讲,一个“应用程序”就是一个Task(默认情况),但是从根本上讲,一个Task是可以有一个或多个Android Application组成的。
Task表示一个任务,每一个Task 会有一个ID作为唯一标识。一个进程(程序)有一个默认的task affinity,默认为包名,也可以多个程序指定同一个TaskAffinity。Activity的启动会进入到对应的Task当中或者重新启动一个新的Task。Android源码里面有一个TaskRecord类,该类的一个实例就对应着一个Task。
一组Task以链表的方式相互连接,每一个Task会有一个前驱任务点和后继任务点,以此来管理Task的编辑和查找。ActivityStack外部以链表的形式管理Task,Task内部以后进先出的历史顺序方式管理Activity。
下面的Task的一段源码,我们可以看到它的主要结构:
final class TaskRecord {
private static final String TAG = TAG_WITH_CLASS_NAME ? "TaskRecord" : TAG_AM;
......
static final String ATTR_TASKID = "task_id";
......
//任务的前驱节点
TaskRecord mPrevAffiliate; // previous task in affiliated chain.
int mPrevAffiliateTaskId = INVALID_TASK_ID; // previous id for persistence.
//该任务的后继节点
TaskRecord mNextAffiliate; // next task in affiliated chain.
int mNextAffiliateTaskId = INVALID_TASK_ID; // next id for persistence.
......
/** List of all activities in the task arranged in history order */
//该Task下的Activity,以后进先出的方式存放
final ArrayList mActivities;
/** 当前的Activity栈 */
ActivityStack stack;
}
Stack表示任务栈,任务栈是以Task为基本单位的。一般我们的程序切换就是Task的切换,一个程序从后台任务栈到前台任务栈,是整个任务栈的移动,而不仅仅是Activity的移动,在任务栈移动之后,再按照LaunchModel的规则对Activity进行操作。与Stack相对应的有Android源码里面的ActivityStack类。一般来说,我们的应用程序都在一个单例的ActivityStack当中。
ActivityStack里面还维护着一个Activity的LRU运行列表,按照最近访问且正在运行的Activity排列。
/**
* 单列的Activity栈
* State and management of a single stack of activities.
*/
final class ActivityStack {
/**
* List of running activities, sorted by recent usage.
* The first entry in the list is the least recently used.
* It contains HistoryRecord objects.
*/
final ArrayList mLRUActivities = new ArrayList<>();
}
这个是使用adb shell dumpsys activity 查看Activity栈信息的时候打印出来的一个LRU的Activity列表。
//LRU的方式管理的正在运行的Activity列表
Running activities (most recent first):
//#276表示该Task的TaskID; A = com.example.malingyi.testtask1 表示该Task的TaskAffinity值,sz = 2表示该Task内部Activity的数量
TaskRecord{51e812a #276 A=com.example.malingyi.testtask1 U=0 sz=2}
Run #3: ActivityRecord{c5e365e u0 com.example.malingyi.testtask1/.ActivityA t276}
TaskRecord{56c2a15 #277 A=com.example.malingyi.testtask2 U=0 sz=2}
Run #2: ActivityRecord{e3bed35 u0 com.example.malingyi.testtask2/.ActivityB t277}
Run #1: ActivityRecord{532f30e u0 com.example.malingyi.testtask2/.MainActivity t277}
TaskRecord{51e812a #276 A=com.example.malingyi.testtask1 U=0 sz=2}
Run #0: ActivityRecord{e5c7c57 u0 com.example.malingyi.testtask1/.MainActivity t276}
//前台正在运行的Activity
mResumedActivity: ActivityRecord{3a73c94 u0 com.example.malingyi.testtask2/.ActivityA t253}
ActivityRecord:代表着一个在Task里面正在活动的Acitivty的信息记录。
/**
* An entry in the history stack, representing an activity.
*/
final class ActivityRecord {
private static final String TAG = TAG_WITH_CLASS_NAME ? "ActivityRecord" : TAG_AM;
...
final ActivityManagerService service; // owner
final IApplicationToken.Stub appToken; // window manager token
final ActivityInfo info; // all about me
final ApplicationInfo appInfo; // information about activity's app
final int userId; // Which user is this running for?
final Intent intent; // the original intent that generated us
final ComponentName realActivity; // the intent component, or target of an alias.
...
//包的名称
final String packageName; // the package implementing intent's component
//进程的名称
final String processName; // process where this component wants to run
//Task的名称
final String taskAffinity; // as per ActivityInfo.taskAffinity
//Activity所在的任务栈
TaskRecord task; // the task this is in.
...
}
ProcessRecord:当前运行的进程信息,描述了该进程的所有信息。
/**
* Full information about a particular process that
* is currently running.
*/
final class ProcessRecord {
...
}
假设:
有两个程序:App1、App2,包名为:App1 = com.example.malingyi.testtask1 App2 = com.example.malingyi.testtask1;
ActivityA属于App1、ActivityB属于App2;两个App都有MainActivity作为启动入口。
启动模式:
ActivityA:standard
ActivityB:standard
App1、App2:MainActivity:standard
TaskAffinity:
都是默认情况下的TaskAffinity(包名)
初始化启动顺序:
Step1:启动App1:MainActivity——>ActivityA ;
Step2:启动App2:MainActivity——>ActivityB;
**栈顶Activity:**ActivityB
Activity栈:
App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB
初始任务栈信息如下:
Stack #8:
Task id #282 //App2的Task栈
TaskRecord{cde1503 #282 A=com.example.malingyi.testtask2 U=0 sz=2} //Task信息
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
Hist #1: ActivityRecord{218b549 u0 com.example.malingyi.testtask2/.ActivityB t282}//Activity信息
Intent { cmp=com.example.malingyi.testtask2/.ActivityB }
ProcessRecord{77bd789 3202:com.example.malingyi.testtask2/u0a63}
Hist #0: ActivityRecord{735919e u0 com.example.malingyi.testtask2/.MainActivity t282}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
ProcessRecord{77bd789 3202:com.example.malingyi.testtask2/u0a63} //进程信息
Task id #281。//App1的Task栈
TaskRecord{8480c80 #281 A=com.example.malingyi.testtask1 U=0 sz=2} //Task信息
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
Hist #1: ActivityRecord{66d10ee u0 com.example.malingyi.testtask1/.ActivityA t281}//Activity信息
Intent { cmp=com.example.malingyi.testtask1/.ActivityA }
ProcessRecord{57c82b9 3305:com.example.malingyi.testtask1/u0a60}
Hist #0: ActivityRecord{157ed43 u0 com.example.malingyi.testtask1/.MainActivity t281}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
ProcessRecord{57c82b9 3305:com.example.malingyi.testtask1/u0a60} //进程信息
切换后任务栈:
Stack #8:
Task id #282 //栈顶还是App2的Task,APP.ActivityA进入了App2的Task栈中。
TaskRecord{cde1503 #282 A=com.example.malingyi.testtask2 U=0 sz=3}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
Hist #2: ActivityRecord{c6170ac u0 com.example.malingyi.testtask1/.ActivityA t282}
Intent { act=com.exaple.malingyi.ActivityA cmp=com.example.malingyi.testtask1/.ActivityA }
ProcessRecord{57c82b9 3305:com.example.malingyi.testtask1/u0a60}
Hist #1: ActivityRecord{218b549 u0 com.example.malingyi.testtask2/.ActivityB t282}
Intent { cmp=com.example.malingyi.testtask2/.ActivityB }
ProcessRecord{77bd789 3202:com.example.malingyi.testtask2/u0a63}
Hist #0: ActivityRecord{735919e u0 com.example.malingyi.testtask2/.MainActivity t282}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
ProcessRecord{77bd789 3202:com.example.malingyi.testtask2/u0a63}
Task id #281
TaskRecord{8480c80 #281 A=com.example.malingyi.testtask1 U=0 sz=2}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
Hist #1: ActivityRecord{66d10ee u0 com.example.malingyi.testtask1/.ActivityA t281}
Intent { cmp=com.example.malingyi.testtask1/.ActivityA }
ProcessRecord{57c82b9 3305:com.example.malingyi.testtask1/u0a60}
Hist #0: ActivityRecord{157ed43 u0 com.example.malingyi.testtask1/.MainActivity t281}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
ProcessRecord{57c82b9 3305:com.example.malingyi.testtask1/u0a60}
初始栈: App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB
操作后的栈:App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB——>App1.ActivityA
这里我们看到,App1.ActivityA重新创建了一个实例进入了App2的Task栈。
任务栈信息:
Task id #282 //栈顶仍然是App2的Task,APP2.ActivityB进入了App2的Task栈中。
TaskRecord{cde1503 #282 A=com.example.malingyi.testtask2 U=0 sz=4}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
Hist #3: ActivityRecord{6e68c29 u0 com.example.malingyi.testtask2/.ActivityB t282}
Intent { act=com.exaple.malingyi.ActivityB cmp=com.example.malingyi.testtask2/.ActivityB }
ProcessRecord{77bd789 3202:com.example.malingyi.testtask2/u0a63}
Hist #2: ActivityRecord{c6170ac u0 com.example.malingyi.testtask1/.ActivityA t282}
Intent { act=com.exaple.malingyi.ActivityA cmp=com.example.malingyi.testtask1/.ActivityA }
ProcessRecord{57c82b9 3305:com.example.malingyi.testtask1/u0a60}
Hist #1: ActivityRecord{218b549 u0 com.example.malingyi.testtask2/.ActivityB t282}
Intent { cmp=com.example.malingyi.testtask2/.ActivityB }
ProcessRecord{77bd789 3202:com.example.malingyi.testtask2/u0a63}
Hist #0: ActivityRecord{735919e u0 com.example.malingyi.testtask2/.MainActivity t282}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
ProcessRecord{77bd789 3202:com.example.malingyi.testtask2/u0a63}
Task id #281
TaskRecord{8480c80 #281 A=com.example.malingyi.testtask1 U=0 sz=2}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
Hist #1: ActivityRecord{66d10ee u0 com.example.malingyi.testtask1/.ActivityA t281}
Intent { cmp=com.example.malingyi.testtask1/.ActivityA }
ProcessRecord{57c82b9 3305:com.example.malingyi.testtask1/u0a60}
Hist #0: ActivityRecord{157ed43 u0 com.example.malingyi.testtask1/.MainActivity t281}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
ProcessRecord{57c82b9 3305:com.example.malingyi.testtask1/u0a60}
初始栈: App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB
操作后的栈:App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB——>App1.ActivityA——>App2.ActivityB
同样,我们看到新启动的ActivityB,还是在原有的App2的Task栈中。
这里的到了两个结论:
启动模式:
ActivityA:SingleTask
ActivityB:SingleTask
App1、App2:MainActivity:standard
TaskAffinity:
都是默认情况下的TaskAffinity(包名)
初始化启动顺序:
Step1:启动App1:MainActivity——>ActivityA ;
Step2:启动App2:MainActivity——>ActivityB;
栈顶Activity:ActivityB
Activity栈:
App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB
初始任务栈:
//所有启动的Activity,按照Task来分组,按照任务的访问顺序从上到下的排列。
Display #0 (activities from top to bottom):
Stack #7:
Task id #277 //App2的Task,里面维护了Activity的入栈顺序
TaskRecord{56c2a15 #277 A=com.example.malingyi.testtask2 U=0 sz=2}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
Hist #1: ActivityRecord{e3bed35 u0 com.example.malingyi.testtask2/.ActivityB t277}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask2/.ActivityB }
ProcessRecord{9d3fb1b 2959:com.example.malingyi.testtask2/u0a63}
Hist #0: ActivityRecord{532f30e u0 com.example.malingyi.testtask2/.MainActivity t277}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
ProcessRecord{9d3fb1b 2959:com.example.malingyi.testtask2/u0a63} //标明Task所属的进程
Task id #276。 //App1的Task,里面维护了Activity的入栈顺序
TaskRecord{51e812a #276 A=com.example.malingyi.testtask1 U=0 sz=2}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.malingyi.testtask1/.MainActivity }
Hist #1: ActivityRecord{c5e365e u0 com.example.malingyi.testtask1/.ActivityA t276}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask1/.ActivityA }
ProcessRecord{7a654b8 2877:com.example.malingyi.testtask1/u0a60}
Hist #0: ActivityRecord{e5c7c57 u0 com.example.malingyi.testtask1/.MainActivity t276}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.malingyi.testtask1/.MainActivity }
ProcessRecord{7a654b8 2877:com.example.malingyi.testtask1/u0a60} //标明Task所属的进程
//正在运行的是App2的ActivityB
mResumedActivity: ActivityRecord{bf1f68 u0 com.example.malingyi.testtask1/com.example.malingyi.testtask2.ActivityB t272}
切换后任务栈:
Stack #7:
Task id #276 //App1的整个栈上移了!不止是Activity移到了前面,同时在Task下的MainActivity也一起移动了。
TaskRecord{51e812a #276 A=com.example.malingyi.testtask1 U=0 sz=2}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.malingyi.testtask1/.MainActivity }
Hist #1: ActivityRecord{c5e365e u0 com.example.malingyi.testtask1/.ActivityA t276}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask1/.ActivityA }
ProcessRecord{7a654b8 2877:com.example.malingyi.testtask1/u0a60}
Hist #0: ActivityRecord{e5c7c57 u0 com.example.malingyi.testtask1/.MainActivity t276}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.malingyi.testtask1/.MainActivity }
ProcessRecord{7a654b8 2877:com.example.malingyi.testtask1/u0a60}
Task id #277 //App2的栈下调了
TaskRecord{56c2a15 #277 A=com.example.malingyi.testtask2 U=0 sz=2}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
Hist #1: ActivityRecord{e3bed35 u0 com.example.malingyi.testtask2/.ActivityB t277}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask2/.ActivityB }
ProcessRecord{9d3fb1b 2959:com.example.malingyi.testtask2/u0a63}
Hist #0: ActivityRecord{532f30e u0 com.example.malingyi.testtask2/.MainActivity t277}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
ProcessRecord{9d3fb1b 2959:com.example.malingyi.testtask2/u0a63}
初始栈: App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB
操作后的栈:App2.ActivityB——>App1.ActivityA——>App1.MainActivity——>App1.ActivityA
原本只是从ActivityA切换到ActivityB,由于ActivityB是SingleTask同时实例已经存在,那么应该是ActivityB移动到ActivityA之前,但是MainActivity也同时移到了ActivityA之前。MainActivity与ActivityA整个Task栈都移动了。按照Task的定义,ActivityStack栈里是按照Task分组来管理Activity,那么有可能APP之间的切换的调度单位会是Task。
切换后任务栈:
Stack #10:
Task id #289 //App1的Task栈移动到了App2的Task栈之前,但是这时情况是MainActivity之前的App1.ActivityA弹出了。Task栈下只剩MainActivity
TaskRecord{fd59417 #289 A=com.example.malingyi.testtask1 U=0 sz=1}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
Hist #0: ActivityRecord{24d5faa u0 com.example.malingyi.testtask1/.MainActivity t289}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
ProcessRecord{219a9ed 3807:com.example.malingyi.testtask1/u0a60}
Task id #290
TaskRecord{1d94004 #290 A=com.example.malingyi.testtask2 U=0 sz=2}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
Hist #1: ActivityRecord{dd07174 u0 com.example.malingyi.testtask2/.ActivityB t290}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask2/.ActivityB }
ProcessRecord{101c022 3830:com.example.malingyi.testtask2/u0a63}
Hist #0: ActivityRecord{2c3fdf1 u0 com.example.malingyi.testtask2/.MainActivity t290}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
ProcessRecord{101c022 3830:com.example.malingyi.testtask2/u0a63}
初始栈: App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB
操作后的栈:App2.ActivityB——>App1.ActivityA——>App1.MainActivity
MainActivity为SingleTask之后,由于它已经存在了一个实例,因此切换的时候会把App1的Task移动到App2的Task之前。然后根据SingleTask的规则,会将Task内在它之前的的Activity弹出,使得它置顶。
到了这里,我们可以得出一个结论:
然后再作出一个假设:
启动模式&TaskAffinity:
App1、App2的MainActivity的LaunchModel = SingleTask, TaskAffinity = 包名;
App1中ActivityA: LaunchModel = SingleTask, TaskAffinity = com.TaskA;
App2中ActivityB: LaunchModel = SingleTask, TaskAffinity = com.TaskB;
初始化启动顺序:
Step1:启动App1:MainActivity——>ActivityA ;
Step2:启动App2:MainActivity——>ActivityB;
栈顶Activity:ActivityB
初始Activity栈:
App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB
初始任务栈:
//我们可以看到,每一个Activity都在一个Task中,按照他们启动的顺序从上倒下。
Stack #11:
Task id #296 //App2.ActivityB的任务栈com.TaskB
TaskRecord{85070a0 #296 A=com.TaskB U=0 sz=1}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask2/.ActivityB }
Hist #0: ActivityRecord{8c75fd1 u0 com.example.malingyi.testtask2/.ActivityB t296}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask2/.ActivityB }
ProcessRecord{f5bf6cc 4090:com.example.malingyi.testtask2/u0a63}
Task id #295 //App2.MainActivity的任务栈com.example.malingyi.testtask2
TaskRecord{850e459 #295 A=com.example.malingyi.testtask2 U=0 sz=1}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
Hist #0: ActivityRecord{52f95ba u0 com.example.malingyi.testtask2/.MainActivity t295}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
ProcessRecord{f5bf6cc 4090:com.example.malingyi.testtask2/u0a63}
Task id #294 //App1.ActivityA的任务栈
TaskRecord{5da881e #294 A=com.TaskA U=0 sz=1}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask1/.ActivityA }
Hist #0: ActivityRecord{43ed667 u0 com.example.malingyi.testtask1/.ActivityA t294}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask1/.ActivityA }
ProcessRecord{d226d15 4068:com.example.malingyi.testtask1/u0a60}
Task id #293 //App1.MainActivity的任务栈
TaskRecord{8b948ff #293 A=com.example.malingyi.testtask1 U=0 sz=1}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
Hist #0: ActivityRecord{7669776 u0 com.example.malingyi.testtask1/.MainActivity t293}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
ProcessRecord{d226d15 4068:com.example.malingyi.testtask1/u0a60}
//正在最前台的Activity
mResumedActivity: ActivityRecord{8c75fd1 u0 com.example.malingyi.testtask2/.ActivityB t296}
从上面的结果可以看出,由于给ActivityA、ActivityB指定了TaskAffinity、SingleTask,两个MainActivity跟随App默认的任务栈,因此每一个Activity都有一个Task任务栈。但还是会按照进程将他们分为两个APP。
注意看ProcessRecord字段会发现,App1.ActivityA和App1.MainActivity1是属于同一个Process(d226d15 4068:com.example.malingyi.testtask1/u0a60)。而App2.ActivityB和App2.MainActivity2是属于另一个
Process(f5bf6cc 4090:com.example.malingyi.testtask2/u0a6)。
切换任务栈:
Stack #11:
Task id #294 //App1.ActivityA所在的任务栈移到了最前面
TaskRecord{5da881e #294 A=com.TaskA U=0 sz=1}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask1/.ActivityA }
Hist #0: ActivityRecord{43ed667 u0 com.example.malingyi.testtask1/.ActivityA t294}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask1/.ActivityA }
ProcessRecord{d226d15 4068:com.example.malingyi.testtask1/u0a60}
Task id #296 //App2.ActivityB所在的任务栈
TaskRecord{85070a0 #296 A=com.TaskB U=0 sz=1}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask2/.ActivityB }
Hist #0: ActivityRecord{8c75fd1 u0 com.example.malingyi.testtask2/.ActivityB t296}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask2/.ActivityB }
ProcessRecord{f5bf6cc 4090:com.example.malingyi.testtask2/u0a63}
Task id #295 //App2.MainActivity所在的任务栈
TaskRecord{850e459 #295 A=com.example.malingyi.testtask2 U=0 sz=1}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
Hist #0: ActivityRecord{52f95ba u0 com.example.malingyi.testtask2/.MainActivity t295}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
ProcessRecord{f5bf6cc 4090:com.example.malingyi.testtask2/u0a63}
Task id #293 //App1.MainActivity所在的任务栈
TaskRecord{8b948ff #293 A=com.example.malingyi.testtask1 U=0 sz=1}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
Hist #0: ActivityRecord{7669776 u0 com.example.malingyi.testtask1/.MainActivity t293}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
ProcessRecord{d226d15 4068:com.example.malingyi.testtask1/u0a60}
Running activities (most recent first):
TaskRecord{5da881e #294 A=com.TaskA U=0 sz=1}
Run #3: ActivityRecord{43ed667 u0 com.example.malingyi.testtask1/.ActivityA t294}
TaskRecord{85070a0 #296 A=com.TaskB U=0 sz=1}
Run #2: ActivityRecord{8c75fd1 u0 com.example.malingyi.testtask2/.ActivityB t296}
TaskRecord{850e459 #295 A=com.example.malingyi.testtask2 U=0 sz=1}
Run #1: ActivityRecord{52f95ba u0 com.example.malingyi.testtask2/.MainActivity t295}
TaskRecord{8b948ff #293 A=com.example.malingyi.testtask1 U=0 sz=1}
Run #0: ActivityRecord{7669776 u0 com.example.malingyi.testtask1/.MainActivity t293}
mResumedActivity: ActivityRecord{43ed667 u0 com.example.malingyi.testtask1/.ActivityA t294}
这里我们看到,只有Task#294(App1.ActivityA)移动到了Task#296(App2.ActivityB)之前,App1.MainActivity所在的Task#293,并没有移动。
初始栈: App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB
操作后的栈:App1.MainActivity——>App2.MainActivity——>App2.ActivityB——>App1.ActivityA
切换任务栈:
Stack #12:
Task id #297 //App1.MainActivity所在的任务栈移到了最前面
TaskRecord{6b63e70 #297 A=com.example.malingyi.testtask1 U=0 sz=1}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
Hist #0: ActivityRecord{f87eb51 u0 com.example.malingyi.testtask1/.MainActivity t297}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask1/.MainActivity bnds=[60,972][180,1092] (has extras) }
ProcessRecord{818d19c 4795:com.example.malingyi.testtask1/u0a60}
Task id #300 //App2.ActivityB所在的任务栈
TaskRecord{d3ee5e9 #300 A=com.TaskB U=0 sz=1}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask2/.ActivityB }
Hist #0: ActivityRecord{3df6276 u0 com.example.malingyi.testtask2/.ActivityB t300}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask2/.ActivityB }
ProcessRecord{d16f7a5 4819:com.example.malingyi.testtask2/u0a63}
Task id #299 //App2.MainActivity所在的任务栈
TaskRecord{90b126e #299 A=com.example.malingyi.testtask2 U=0 sz=1}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
Hist #0: ActivityRecord{9778bab u0 com.example.malingyi.testtask2/.MainActivity t299}
Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.example.malingyi.testtask2/.MainActivity bnds=[236,972][356,1092] (has extras) }
ProcessRecord{d16f7a5 4819:com.example.malingyi.testtask2/u0a63}
Task id #298 //App1.ActivityA所在的任务栈
TaskRecord{8688d0f #298 A=com.TaskA U=0 sz=1}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask1/.ActivityA }
Hist #0: ActivityRecord{f78be54 u0 com.example.malingyi.testtask1/.ActivityA t298}
Intent { flg=0x10000000 cmp=com.example.malingyi.testtask1/.ActivityA }
ProcessRecord{818d19c 4795:com.example.malingyi.testtask1/u0a60}
我重新启动了一次APP,因此Task#ID改变了,但是他们初始的启动顺序没变。
初始栈: App1.MainActivity——>App1.ActivityA——>App2.MainActivity——>App2.ActivityB。
操作后的栈:App1.ActivityA——>App2.MainActivity——>App2.ActivityB——>App1.MainActivity
我们仍然看到,只有Task#297 (App1.MainActivity)移动到了Task#300(App2.ActivityB)之前,App1.ActivityA所在的Task#298。
到了这里,假设已经得到了实践的验证:
standard模式下,Activity会进入启动它的Activity所在的Task栈中,这个结论对于在启动其他App的Activity也成立。
LaunchModel的启动规则,在跨App之间时启动Activity同样成立。
在APP之间切换时。首先,会将切换的App所在的Task移动到最前面;然后,再使用LaunchModel的规则对Activity进行出栈入栈的操作。
Android的APP切换,实际上是以Task为单位来进行切换,将被选中的Activity所在的Task移动到Stack任务栈的最前端,然后在Task内部根据Activity的启动模式,使用LaunchModel规则对Task内部的Activity进行操作。