几乎99%的情况下，Android应用程序不需要接管自己的生命周期。大多数情况下，这归结于更好的计划或更聪明的应用程序设计。例如，构建一个内部服务(不导出)来处理下载等，或者围绕用户工作流设计动作和任务。

但话虽如此，有志者事竟成。Android通过Android .os. process类提供了一个比Java更好的API来控制底层进程。与Java不同的是，它不会把开发人员当成傻瓜，把所有问题都隐藏在一个简单的Java .lang. system .exit()调用之后。

那么如何让你的应用在Android中自杀呢?诀窍很简单:

通过继承标准Android .app. application类来创建自己的Android应用程序类(记得在AndroidManifest.xml文件中声明它)。

重写onCreate()方法，并存储启动应用程序的进程ID:

this.pid = android.os.Process.myPid(); // Save for later use.

现在要杀死你的应用程序，提供一个kill()方法:

android.os.Process.sendSignal(pid, android.os.Process.SIGNAL_KILL);

现在，无论何时你需要你的应用自杀，只要输入转换应用上下文，并调用你的kill方法!

((MySuicidalApp) context.getApplicationContext()).kill()

请记住，由于Android中的进程管理策略，特别是与服务相关的策略，Android可能只是选择重新启动你的服务(参见你不应该在Android上使用任务杀手)。

All of my applications have quit buttons... and I quite frequently get positive comments from users because of it. I don't care if the platform was designed in a fashion that applications shouldn't need them. Saying "don't put them there" is kind of ridiculous. If the user wants to quit... I provide them the access to do exactly that. I don't think it reduces how Android operates at all and seems like a good practice. I understand the life cycle... and my observation has been that Android doesn't do a good job at handling it.... and that is a basic fact.

我只是想在这里为这篇文章的未来读者补充一个更正。这个细微的差别我已经不理解很长一段时间了，所以我想确保你们没有人会犯同样的错误:

如果栈上有多个activity, System.exit()不会杀死你的应用。实际发生的情况是进程被杀死，并立即重新启动，堆栈上少了一个活动。当你的应用程序被强制关闭对话框杀死时，甚至当你试图从DDMS中杀死进程时，也会发生这种情况。据我所知，这是一个完全没有记录的事实。

The short answer is, if you want to exit your application, you've got to keep track of all activities in your stack and finish() ALL of them when the user wants to exit (and no, there is no way to iterate through the Activity stack, so you have to manage all of this yourself). Even this does not actually kill the process or any dangling references you may have. It simply finishes the activities. Also, I'm not sure whether Process.killProcess(Process.myPid()) works any better; I haven't tested it.

另一方面，如果你可以将活动保留在堆栈中，还有另一个方法可以让事情变得超级简单:Activity.moveTaskToBack(true)将简单地将你的进程作为背景并显示主屏幕。

长的答案包括对这种行为背后的哲学的解释。这一理论是基于以下几个假设:

First of all, this only happens when your app is in the foreground. If it is in the background the process will terminate just fine. However, if it is in the foreground, the OS assumes that the user wants to keep doing whatever he/she was doing. (If you are trying to kill the process from DDMS, you should hit the home button first, and then kill it) It also assumes that each activity is independent of all the other activities. This is often true, for example in the case that your app launches the Browser Activity, which is entirely separate and was not written by you. The Browser Activity may or may not be created on the same Task, depending on its manifest attributes. It assumes that each of your activities is completely self-reliant and can be killed/restored in a moment's notice. (I rather dislike this particular assumption, since my app has many activities which rely on a large amount of cached data, too large to be efficiently serialized during onSaveInstanceState, but whaddya gonna do?) For most well-written Android apps this should be true, since you never know when your app is going to be killed off in the background. The final factor is not so much an assumption, but rather a limitation of the OS: killing the app explicitly is the same as the app crashing, and also the same as Android killing the app to reclaim memory. This culminates in our coup de grace: since Android can't tell if the app exited or crashed or was killed in the background, it assumes the user wants to return where they left off, and so the ActivityManager restarts the process.

仔细想想，这是适合这个平台的。首先，这正是当进程在后台被杀死，用户返回到它时所发生的情况，因此它需要在它停止的地方重新启动。其次，这是当应用程序崩溃并呈现可怕的强制关闭对话框时所发生的情况。

Say I want my users to be able to take a picture and upload it. I launch the Camera Activity from my activity, and ask it to return an image. The Camera is pushed onto the top of my current Task (rather than being created in its own Task). If the Camera has an error and it crashes, should that result in the whole app crashing? From the standpoint of the user, only the Camera failed, and they should be returned to their previous activity. So it just restarts the process with all the same Activities in the stack, minus the Camera. Since your Activities should be designed so that they can be killed and restored at the drop of a hat, this shouldn't be a problem. Unfortunately, not all apps can be designed that way, so it is a problem for many of us, no matter what Romain Guy or anyone else tells you. So, we need to use workarounds.

所以，我最后的建议是:

Don't try to kill the process. Either call finish() on all activities or call moveTaskToBack(true). If your process crashes or gets killed, and if, like me, you need the data that was in memory which is now lost, you'll need to return to the root activity. To do this, you should call startActivity() with an Intent that contains the Intent.FLAG_ACTIVITY_CLEAR_TOP flag. If you want to kill your app from the Eclipse DDMS perspective, it had better not be in the foreground, or it will restart itself. You should press the Home button first, and then kill the process.

如果没有退出函数，应用程序开发人员就可以杀死自己的应用程序，这是非常糟糕的设计。

我的应用程序需要允许用户在运行时动态地更改数据，用户需要重新启动我的应用程序才能使更改生效，但Android不允许我的应用程序自行重新启动。Android操作系统有一个非常糟糕的设计应用程序生命周期。

这是一个有这么多专家参与的有趣而有见地的讨论。我觉得这篇文章应该从Android开发的主要网站中循环回来，因为它确实围绕着Android操作系统的核心设计之一。

我还想在这里发表我的意见。

到目前为止，我对Android处理生命周期事件的方式印象深刻，它将类似web的体验概念引入原生应用。

话虽如此，我仍然认为应该有一个退出按钮。为什么?．.． 不是为了我，不是为了泰德，也不是为了在座的任何一位技术大师，而是为了满足终端用户的需求。

虽然我不是Windows的忠实粉丝，但很久以前他们引入了一个大多数终端用户都习惯的概念(X按钮)……“我想在‘我’想要的时候停止运行一个小部件”。

这并不意味着有人(操作系统、开发人员?)会根据自己的判断来处理……它仅仅意味着“我习惯的红色X按钮在哪里”。我的行为应该类似于“按下按钮结束通话”，“按下按钮关闭设备”，等等……这是一种感知。它本身带来了一种满足感，我的行动确实达到了目的。

尽管开发人员可以使用这里给出的建议来欺骗这种行为，但仍然存在这样的看法，即应用程序应该完全停止运行(现在)，由最终用户要求的独立、可信和中立的来源(OS)。

回答:(罗曼盖伊):用户不需要，系统会处理这个问题 自动。这就是活动生命周期(特别是 onPause/onStop/onDestroy)用于。无论你做什么，都不要放不下 “退出”或“退出”应用程序按钮。这在安卓系统中毫无用处 应用程序模型。这也与核心应用程序的方式相反 工作。

1: Totally exiting an application may be generally unmandatory, but it is not useless. What if windows had no exit option? System would be doggy slow as memory was full and the OS had to guess at which programs you were done with. I don't care what Romain Guy or even Larry Page and Sergey Brin say - these are unquestionable facts: Systems run slower when they have to kill tasks to get their memory before a new app can be launched. You just can't tell me that it doesn't take time to kill an app! Even the light from distant stars take time... There is some use in allowing the user to fully close apps.

2:与核心应用程序的工作方式相反?这是什么意思?当我现在运行一个应用程序时，它不再做任何工作……它只是在需要内存时等待被操作系统杀死。

总而言之，最小化和退出之间有明显的区别，两者都不适合对方。每个螺丝上都留个螺丝刀吗?还是每扇门都有钥匙?我们是不是把所有的电器都开着，直到断路器爆炸，我们需要打开另一个电器?我们是不是把洗碗机里装满了盘子，每次只拿出足够的空间来放一些新的脏盘子?我们把所有的车都停在车道上，直到——哦，算了。

如果用户想要最小化应用程序，那么最好的方法就是最小化它。如果用户想要退出应用程序，那么无论如何最好是退出。

这会让人皱眉吗?这是Android的观点——他们不赞成。许多独立的Android新手开发者对此表示不满。

但当它落到实处时，有好的编码和坏的编码。有好的程序流模型也有坏的程序流模型。

当用户知道他们已经用完了程序时，把程序留在内存中并不是好的程序流程。它完全没有任何用处，而且在启动新应用程序或运行应用程序分配更多内存时，它会减慢运行速度。

这有点像你的汽车:有时你让它一直开着，比如在红绿灯前停车，或者在快餐店经过时停车，或者在自动取款机前停车。但在其他情况下，你确实想把它关掉——比如当你去工作的时候，或者在杂货店，甚至在家里。

同样地，如果你正在玩游戏，这时手机响了。暂停游戏并继续运行。但如果用户已经玩了一段时间，那就让他们退出游戏吧。

The exit button on some applications should be more out in front than others. Games, for example, or programs where the user is likely to want to fully exit, should have an obvious exit. Other programs, like, perhaps, email programs, where exiting is an unlikely desire (so that it can keep checking for email) -- these programs should not waste prime control input screen space with an exit option, but for good program flow, it should have an exit option. What if someone decides they don't want their mail program trying to check email when they are in poor coverage area, or maybe in a Skype call or whatever? Let them exit the email program if they want!

暂停和退出是两项至关重要的任务，两者都不能实现对方的作用。