blocks|key|2801526|text|对于Application类，生产设备上没有这样的回调。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2801527|您想要做的事情通常应该在更改完成后立即完成，或者在相应应用程序组件的onPause()中完成。|offset|length|style|CODE|2801528|entityMap^0|0|Y|9|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

There is no such call back on a production device for the Application class.

The things you want to do should usually be done right after the changes are made, or in the <code>onPause()</code> of the respective app component.

blocks|key|187527|text|在android中，没有关闭应用程序的概念。用户只是离开:这是您将知道的唯一事件(活动中的onPause())。你应该设计你的应用程序，让它适合这个生命周期。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|187528|通常，您应该立即但异步地保存任何更改，这样UI就不会挂起。这比在onPause()中保存更改要好得多，因为如果在应用程序暂停之前发生了一些不好的事情(应用程序崩溃，用户电池耗尽)，所有数据都已经正确保存。|187529|SharedPreferences已经异步保存更改，所以如果您使用它，您将没有其他事情可做。否则，您可以使用Kotlin协程，或者如果您使用Java，很好的旧AsyncTask是很好的。|187530|entityMap^0|19|9|0|W|9|0|0|H|27|9|0^^$0|@$1|2|3|4|5|6|7|L|8|@$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|R|8|@$9|S|A|T|B|C]|$9|U|A|V|B|C]]|D|@]|E|$]]|$1|J|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|K|$]]

In android, there is no concept of closing an app. The user just leaves: this is the only event that you will be aware of (<code>onPause()</code> in an activity). You should design your app so that it fits this lifecycle.

Typically, you should save any changes immediately but asynchronously, so that the UI doesn't hang. This is much better than saving changes in <code>onPause()</code> because if something bad happens before the app is paused (the app crashes, the user runs out of battery), all data was already saved properly.

<code>SharedPreferences</code> already save changes asynchronously so if you use that, you have nothing else to do. Otherwise you can use Kotlin coroutines or if you use Java, the good old <code>AsyncTask</code> is great.

blocks|key|2801613|text|你可以在Activity中重写onDestroy()，它将是你应用程序中最后一个关闭的，并检查它是否正在完成。在这种情况下，您的代码将不会在设备轮换时调用。但您应该知道，当应用程序通过设备主页按钮关闭时，onDestroy()不会被调用。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2801614|@Override
public+void+onDestroy(){
++++super.onDestroy();
++++if(isFinishing()){
++++++++//do+your+stuff+here
++++}
}|code-block|syntax|javascript|2801615|entityMap^0|4|8|F|B|2U|B|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|U|8|@]|D|@]|E|$]]]|L|$]]

You can override <code>onDestroy()</code> in the <code>Activity</code> which will be the last one closed in your app and check if it's finishing. In this case your code will not be invoked on a device rotation. But you should be aware that <code>onDestroy()</code> is not invoked when an app is closed through device home button.

<pre><code>@Override
public void onDestroy(){
 super.onDestroy();
 if(isFinishing()){
 //do your stuff here
 }
}
</code></pre>

blocks|key|3013815|text|首先:我是一个绝对的初学者|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3013816|当我的应用程序退出时，我需要执行一些代码(是的，我知道Android中没有这样的事情)，这对我来说没问题：|3013817|-I具有扩展应用程序的MyApplication。作为MyApplication的成员，有一个名为activeActivitiesNumber的AtomicInteger字段和一个公共getter方法。|3013818|-All应用程序活动扩展了MyActivy+(它本身扩展了活动)|3013819|-MyActivity覆盖了onCreate、onResume和onStop方法，并且还有一个protected字段:+Protected+MyAppication+mAppState；|3013820|a)+OnCreate(){
super.onCreate();
mAppState=this.getApplication();...}


b)+onResume(){
super.OnResume();
myAppState.getactiveActivitiesNumber().addAndGet(1)
....}

c)+onStop(){
super.onStop()

if+(myAppStatemyAppState.getactiveActivitiesNumber()..decrementAndGet()<1){
...call+exiting+code+(for+instance+a+public+method+defined+in+MyApplication}
}|code-block|syntax|javascript|3013821|它有一个问题:如果你启动了任何不属于你的应用程序的活动(例如，发送一封电子邮件)，它将触发退出方法。|3013822|另一个问题(不知道它是否是真正的理论问题)是在某些情况下不能保证会调用onStop。|3013823|希望这能有所帮助。|3013824|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|Y|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|Z|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|10|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|11|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|12|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|14|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

First of all: I'm an absolute beginner

I need to execute some code when my app exits (yes, I know not such thing in Android) and this works ok for me:

-I have MyApplication wich extends Application. As a member of MyApplication there is an AtomicInteger field named activeActivitiesNumber and a public getter method.

-All the application activities extend MyActivy (which itself extendes Activity) 

-MyActivity overrides onCreate, onResume and onStop methods and also have a protected field: 
Protected MyAppication mAppState;

<pre><code>a) OnCreate(){
super.onCreate();
mAppState=this.getApplication();...}


b) onResume(){
super.OnResume();
myAppState.getactiveActivitiesNumber().addAndGet(1)
....}

c) onStop(){
super.onStop()

if (myAppStatemyAppState.getactiveActivitiesNumber()..decrementAndGet()&lt;1){
...call exiting code (for instance a public method defined in MyApplication}
}
</code></pre>

It has a problem: if you start any activity tan doesn´t belong to your application (for instance send an email) it will fire the exiting method.

Another problem (don´t know if it is a real o theoretical one) is that there is no guarantee tan in some situations onStop will be called.

Hope this help.

blocks|key|2801632|text|您可以通过以下回调在应用程序类中使用registerActivityLifecycleCallbacks()+(我建议创建一个扩展ActivityLifecycleCallbacks的AppLifecycleCallbacks类)：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2801633|public+interface+ActivityLifecycleCallbacks+{
++++void+onActivityCreated(Activity+activity,+Bundle+savedInstanceState);
++++void+onActivityStarted(Activity+activity);
++++void+onActivityResumed(Activity+activity);
++++void+onActivityPaused(Activity+activity);
++++void+onActivityStopped(Activity+activity);
++++void+onActivitySaveInstanceState(Activity+activity,+Bundle+outState);
++++void+onActivityDestroyed(Activity+activity);
}|code-block|syntax|javascript|2801634|entityMap^0|I|10|1T|Q|2K|L|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|U|8|@]|D|@]|E|$]]]|L|$]]

You can use <code>registerActivityLifecycleCallbacks()</code> in the Application class with the following callbacks (I recommend creating an <code>AppLifecycleCallbacks</code> class that extends the <code>ActivityLifecycleCallbacks</code>):

<pre><code>public interface ActivityLifecycleCallbacks {
 void onActivityCreated(Activity activity, Bundle savedInstanceState);
 void onActivityStarted(Activity activity);
 void onActivityResumed(Activity activity);
 void onActivityPaused(Activity activity);
 void onActivityStopped(Activity activity);
 void onActivitySaveInstanceState(Activity activity, Bundle outState);
 void onActivityDestroyed(Activity activity);
}
</code></pre>

blocks|key|3013924|text|现在可以使用DefaultLifecycleObserver了，我在下面举了个例子|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3013925|public+class+YourApplication+extends+Application+implements+DefaultLifecycleObserver+{

@Override
public+void+onCreate()+{
//Do+your+onCreate+things
}

@Override
public+void+onStop(@NonNull+@NotNull+LifecycleOwner+owner)+{
++++//Do+your+onStop+things
}

@Override
public+void+onDestroy(@NonNull+@NotNull+LifecycleOwner+owner)+{
++++//Do+your+onDestroy+things
}
}|code-block|syntax|javascript|3013926|您可以检测到onStart+onCreate+onDestroy+onResume+onPause+onStop，它工作得非常好|3013927|entityMap^0|6|O|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

It's now possible with the <code>DefaultLifecycleObserver</code> I put an exemple below
<pre><code>public class YourApplication extends Application implements DefaultLifecycleObserver {

@Override
public void onCreate() {
//Do your onCreate things
}

@Override
public void onStop(@NonNull @NotNull LifecycleOwner owner) {
 //Do your onStop things
}

@Override
public void onDestroy(@NonNull @NotNull LifecycleOwner owner) {
 //Do your onDestroy things
}
}
</code></pre>
You can detect onStart onCreate onDestroy onResume onPause onStop this works very well

I am extending Application class to work with some global variables that need context. I know there is onCreate() method in the Application class that gets called before any other onCreate() in activities, but I would like to know if there is onDestroy() or similar method in the Application class that could be overridden so that I would be able to store variables in persistent memory, unregister listener and send last message to server before app process gets killed? If not, is there any other way to do that?

Android: onDestroy() or similar method in Application class

服务器

Android

Kotlin

Java

我正在扩展Application类来处理一些需要上下文的全局变量。我知道在应用程序类中有onCreate()方法，它在活动中的任何其他onCreate()之前被调用，但是我想知道在应用程序类中是否有onDestroy()或类似的方法可以被覆盖，这样我就能够在应用程序进程被杀死之前将变量存储在永久内存中，注销侦听器并发送最后一条消息到服务器？如果没有，有没有其他方法呢？

问Android:应用程序类中的onDestroy()或类似方法
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