blocks|key|953343|text|这是用于检查特定服务是否正在运行的代码。我敢肯定，只要您用getRunningAppProcesses()或getRunningTasks()更改getRunningServices，它也可以适用于某个活动。看看这里，http://developer.android.com/reference/android/app/ActivityManager.html#getRunningAppProcesses()|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|953344|相应地更改Constants.PACKAGE和Constants.BACKGROUND_SERVICE_CLASS|953345|++++public+static+boolean+isServiceRunning(Context+context)+{

++++Log.i(TAG,+"Checking+if+service+is+running");

++++ActivityManager+activityManager+=+(ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);

++++List<RunningServiceInfo>+services+=+activityManager.getRunningServices(Integer.MAX_VALUE);

++++boolean+isServiceFound+=+false;

++++for+(int+i+=+0;+i+<+services.size();+i%2B%2B)+{

++++++++if+(Constants.PACKAGE.equals(services.get(i).service.getPackageName())){

++++++++++++if+(Constants.BACKGROUND_SERVICE_CLASS.equals(services.get(i).service.getClassName())){
++++++++++++++++isServiceFound+=+true;
++++++++++++}
++++++++}
++++}

++++Log.i(TAG,+"Service+was"+%2B+(isServiceFound+?+""+:+"+not")+%2B+"+running");

++++return+isServiceFound;

}|code-block|syntax|javascript|953346|entityMap|0|LINK|mutability|MUTABLE|url|http://developer.android.com/reference/android/app/ActivityManager.html#getRunningAppProcesses()^0|31|2O|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|X|8|@]|9|@]|C|$I|J]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

This is code for checking whether a particular service is running. I'm fairly sure it can work for an activity too as long as you change getRunningServices with getRunningAppProcesses() or getRunningTasks(). Have a look here <a href="http://developer.android.com/reference/android/app/ActivityManager.html#getRunningAppProcesses()" rel="noreferrer">http://developer.android.com/reference/android/app/ActivityManager.html#getRunningAppProcesses()</a>

Change Constants.PACKAGE and Constants.BACKGROUND_SERVICE_CLASS accordingly

<pre><code> public static boolean isServiceRunning(Context context) {

 Log.i(TAG, "Checking if service is running");

 ActivityManager activityManager = (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);

 List&lt;RunningServiceInfo&gt; services = activityManager.getRunningServices(Integer.MAX_VALUE);

 boolean isServiceFound = false;

 for (int i = 0; i &lt; services.size(); i++) {

 if (Constants.PACKAGE.equals(services.get(i).service.getPackageName())){

 if (Constants.BACKGROUND_SERVICE_CLASS.equals(services.get(i).service.getClassName())){
 isServiceFound = true;
 }
 }
 }

 Log.i(TAG, "Service was" + (isServiceFound ? "" : " not") + " running");

 return isServiceFound;

}
</code></pre>

blocks|key|953424|text|您可以在活动中使用static变量。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|953425|class+MyActivity+extends+Activity+{
+++++static+boolean+active+=+false;

++++++@Override
++++++public+void+onStart()+{
+++++++++super.onStart();
+++++++++active+=+true;
++++++}+

++++++@Override
++++++public+void+onStop()+{
+++++++++super.onStop();
+++++++++active+=+false;
++++++}
}|code-block|syntax|javascript|953426|唯一的问题是，如果你在两个相互链接的活动中使用它，那么第一个活动中的onStop有时会在第二个活动中的onStart之后被调用。因此，这两种观点可能都是正确的。|953427|这取决于您尝试执行的操作(从服务更新当前活动？)。您只需在activity+onStart方法中的服务中注册一个静态侦听器，然后当您的服务想要更新UI时，正确的侦听器将可用。|953428|entityMap^0|9|6|0|0|Y|6|1F|7|0|12|7|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|O|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|P|$]]

You can use a <code>static</code> variable within the activity.

<pre><code>class MyActivity extends Activity {
 static boolean active = false;

 @Override
 public void onStart() {
 super.onStart();
 active = true;
 } 

 @Override
 public void onStop() {
 super.onStop();
 active = false;
 }
}
</code></pre>

The only gotcha is that if you use it in two activities that link to each other then <code>onStop</code> on the first is sometimes called after <code>onStart</code> in second. So both might be true briefly.

Depending on what you are trying to do (update the current activity from a service?). You could just register a static listener in the service in your activity <code>onStart</code> method then the correct listener will be available when your service wants to update the UI.

blocks|key|737417|text|谢谢kkudi！我可以把你的答案改编成一个活动...以下是在我的应用程序中起作用的方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|737418|public+boolean+isServiceRunning()+{+

ActivityManager+activityManager+=+(ActivityManager)Monitor.this.getSystemService+(Context.ACTIVITY_SERVICE);+
++++List<RunningTaskInfo>+services+=+activityManager.getRunningTasks(Integer.MAX_VALUE);+
++++isServiceFound+=+false;+
++++for+(int+i+=+0;+i+<+services.size();+i%2B%2B)+{+
++++++++if+(services.get(i).topActivity.toString().equalsIgnoreCase("ComponentInfo{com.lyo.AutoMessage/com.lyo.AutoMessage.TextLogList}"))+{
++++++++++++isServiceFound+=+true;
++++++++}
++++}+
++++return+isServiceFound;+
}+|code-block|syntax|javascript|737419|如果topActivity与用户正在做的事情相匹配，此示例将为您提供true或false。因此，如果您检查的活动没有显示(即onPause)，那么您将不会得到匹配。此外，要执行此操作，您需要将权限添加到清单中。|737420|<uses-permission++android:name="android.permission.GET_TASKS"/>|737421|我希望这对你有帮助！|737422|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

thanks kkudi! I was able to adapt your answer to work for an activity... here's what worked in my app..

<pre><code>public boolean isServiceRunning() { 

ActivityManager activityManager = (ActivityManager)Monitor.this.getSystemService (Context.ACTIVITY_SERVICE); 
 List&lt;RunningTaskInfo&gt; services = activityManager.getRunningTasks(Integer.MAX_VALUE); 
 isServiceFound = false; 
 for (int i = 0; i &lt; services.size(); i++) { 
 if (services.get(i).topActivity.toString().equalsIgnoreCase("ComponentInfo{com.lyo.AutoMessage/com.lyo.AutoMessage.TextLogList}")) {
 isServiceFound = true;
 }
 } 
 return isServiceFound; 
} 
</code></pre>

this example will give you a true or false if the topActivity matches what the user is doing. So if the activity your checking for is not being displayed (i.e. is onPause) then you won't get a match. Also, to do this you need to add the permission to your manifest..

<pre><code>&lt;uses-permission android:name="android.permission.GET_TASKS"/&gt;
</code></pre>

I hope this was helpful!

blocks|key|737454|text|我这样想得更清楚：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|737455|++public+boolean+isRunning(Context+ctx)+{
++++++++ActivityManager+activityManager+=+(ActivityManager)+ctx.getSystemService(Context.ACTIVITY_SERVICE);
++++++++List<RunningTaskInfo>+tasks+=+activityManager.getRunningTasks(Integer.MAX_VALUE);

++++++++for+(RunningTaskInfo+task+:+tasks)+{
++++++++++++if+(ctx.getPackageName().equalsIgnoreCase(task.baseActivity.getPackageName()))+
++++++++++++++++return+true;++++++++++++++++++++++++++++++++++
++++++++}

++++++++return+false;
++++}|code-block|syntax|javascript|737456|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I think more clear like that:

<pre><code> public boolean isRunning(Context ctx) {
 ActivityManager activityManager = (ActivityManager) ctx.getSystemService(Context.ACTIVITY_SERVICE);
 List&lt;RunningTaskInfo&gt; tasks = activityManager.getRunningTasks(Integer.MAX_VALUE);

 for (RunningTaskInfo task : tasks) {
 if (ctx.getPackageName().equalsIgnoreCase(task.baseActivity.getPackageName())) 
 return true; 
 }

 return false;
 }
</code></pre>

blocks|key|737535|text|我使用了MyActivity.class和getCanonicalName方法，并得到了答案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|737536|protected+Boolean+isActivityRunning(Class+activityClass)
{
++++++++ActivityManager+activityManager+=+(ActivityManager)+getBaseContext().getSystemService(Context.ACTIVITY_SERVICE);
++++++++List<ActivityManager.RunningTaskInfo>+tasks+=+activityManager.getRunningTasks(Integer.MAX_VALUE);

++++++++for+(ActivityManager.RunningTaskInfo+task+:+tasks)+{
++++++++++++if+(activityClass.getCanonicalName().equalsIgnoreCase(task.baseActivity.getClassName()))
++++++++++++++++return+true;
++++++++}

++++++++return+false;
}|code-block|syntax|javascript|737537|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I used MyActivity.class and getCanonicalName method and I got answer.

<pre><code>protected Boolean isActivityRunning(Class activityClass)
{
 ActivityManager activityManager = (ActivityManager) getBaseContext().getSystemService(Context.ACTIVITY_SERVICE);
 List&lt;ActivityManager.RunningTaskInfo&gt; tasks = activityManager.getRunningTasks(Integer.MAX_VALUE);

 for (ActivityManager.RunningTaskInfo task : tasks) {
 if (activityClass.getCanonicalName().equalsIgnoreCase(task.baseActivity.getClassName()))
 return true;
 }

 return false;
}
</code></pre>

blocks|key|737635|text|如果您对活动的特定实例的生命周期状态感兴趣，siliconeagle的解决方案看起来是正确的，只是新的“活动”变量应该是实例变量，而不是静态变量。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|737636|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

If you are interested in the lifecycle state of the specific instance of the activity, siliconeagle's solution looks correct except that the new "active" variable should be an instance variable, rather than static.

blocks|key|737702|text|使用有序广播。请参阅http://android-developers.blogspot.nl/2011/01/processing-ordered-broadcasts.html|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|737703|在您的活动中，在onStart中注册一个接收器，在onStop中取消注册。现在，例如，当服务需要处理活动可能做得更好的事情时，从服务发送一个有序的广播(在服务本身中有一个默认的处理程序)。现在，您可以在活动运行时在活动中进行响应。该服务可以检查结果数据，以查看是否处理了广播，如果没有，则采取适当的行动。|737704|entityMap|0|LINK|mutability|MUTABLE|url|http://android-developers.blogspot.nl/2011/01/processing-ordered-broadcasts.html^0|A|28|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

Use an ordered broadcast. See <a href="http://android-developers.blogspot.nl/2011/01/processing-ordered-broadcasts.html" rel="nofollow">http://android-developers.blogspot.nl/2011/01/processing-ordered-broadcasts.html</a>

In your activity, register a receiver in onStart, unregister in onStop. Now when for example a service needs to handle something that the activity might be able to do better, send an ordered broadcast from the service (with a default handler in the service itself). You can now respond in the activity when it is running. The service can check the result data to see if the broadcast was handled, and if not take appropriate action.

blocks|key|953738|text|不使用任何辅助变量的选项为：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|953739|activity.getWindow().getDecorView().getRootView().isShown()|code-block|syntax|javascript|953740|其中activity是f.e.：this或getActivity()。|953741|此表达式返回的值在onStart()+/+onStop()中更改，这是开始/停止显示电话上活动布局的事件。|953742|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

An option without using any auxiliar variable is:

<pre><code>activity.getWindow().getDecorView().getRootView().isShown()
</code></pre>

where activity is f.e.: this or getActivity().

The value returned by this expression changes in onStart() / onStop(), which are the events that start / stop showing the layout of the activity on the phone.

blocks|key|953787|text|除了the+accepted+answer之外，如果您有多个activity实例，则可以使用计数器来处理多个实例：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|953788|class+MyActivity+extends+Activity+{

+++++static+int+activeInstances+=+0;

+++++static+boolean+isActive()+{
++++++++return+(activeInstances+>+0);
+++++}

++++++@Override
++++++public+void+onStart()+{
+++++++++super.onStart();
+++++++++activeInstances%2B%2B;
++++++}+

++++++@Override
++++++public+void+onStop()+{
+++++++++super.onStop();
+++++++++activeInstances--;
++++++}
}|code-block|syntax|javascript|953789|entityMap|0|LINK|mutability|MUTABLE|url|//stackoverflow.com/questions/5446565/android-how-do-i-check-if-activity-is-running/5446680#5446680^0|2|J|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

In addition to <a href="//stackoverflow.com/questions/5446565/android-how-do-i-check-if-activity-is-running/5446680#5446680">the accepted answer</a>, if you have multiple instances of the activity, you can use a counter instead to handle multiple instances :
<pre><code>class MyActivity extends Activity {

 static int activeInstances = 0;

 static boolean isActive() {
 return (activeInstances &gt; 0);
 }

 @Override
 public void onStart() {
 super.onStart();
 activeInstances++;
 } 

 @Override
 public void onStop() {
 super.onStop();
 activeInstances--;
 }
}
</code></pre>

blocks|key|953823|text|我使用了check+if+(!a.isFinishing())，它似乎可以做我需要的事情。a是活动实例。这是不正确的吗？为什么没人试一下呢？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|953824|entityMap^0|A|L|19|1|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

I used a check <code>if (!a.isFinishing())</code> and it seems to do what i need. <code>a</code> is the activity instance. Is this incorrect? Why didn't anyone try this?

blocks|key|953861|text|使用以下代码找到了一种简单的解决方法|type|unstyled|depth|inlineStyleRanges|entityRanges|data|953862|@Override+
protected+void+onCreate(Bundle+savedInstanceState)+{+
++++++++++++super.onCreate(savedInstanceState);+
++++++++++++if+((getIntent().getFlags()+&+Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT)+!=+0)+{+
++++++++++++++++//+Activity+is+being+brought+to+front+and+not+being++created+again,+
++++++++++++++++//+Thus+finishing+this+activity+will+bring+the+last+viewed+activity+to+foreground
++++++++++++++++finish();+
++++++++++++}+
++++}|code-block|syntax|javascript|953863|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Found an easy workaround with the following code

<pre><code>@Override 
protected void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 if ((getIntent().getFlags() &amp; Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT) != 0) { 
 // Activity is being brought to front and not being created again, 
 // Thus finishing this activity will bring the last viewed activity to foreground
 finish(); 
 } 
 }
</code></pre>

blocks|key|953945|text|我认为公认的答案是一种糟糕的处理方式。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|953946|我不知道用例是什么，但请考虑基类中的受保护方法|953947|@protected
void+doSomething()+{
}|code-block|syntax|javascript|953948|并在派生类中重写它。|953949|当事件发生时，只需在基类中调用此方法即可。正确的“活动”类将会处理它。然后，类本身可以检查它是否不是Paused()。|offset|length|style|CODE|953950|更好的方法是使用像GreenRobot's、Square's这样的事件总线，但该总线已被弃用，建议使用RxJava|953951|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/greenrobot/EventBus|1|http://square.github.io/otto/|2|http://blog.kaush.co/2014/12/24/implementing-an-event-bus-with-rxjava-rxbus/^0|0|0|0|0|1E|8|0|9|C|0|M|8|1|1F|6|2|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|15|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|16|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|17|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|18|8|@$M|19|N|1A|O|P]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1B|8|@]|9|@$M|1C|N|1D|1|1E]|$M|1F|N|1G|1|1H]|$M|1I|N|1J|1|1K]]|A|$]]|$1|S|3|-4|5|6|7|1L|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]|10|$5|V|W|X|A|$Y|11]]|12|$5|V|W|X|A|$Y|13]]]]

I think the accepted answer is an awful way of handling this.

I don't know what the use case is, but please consider a protected method in the base class

<pre><code>@protected
void doSomething() {
}
</code></pre>

and override it in the derived class. 

When the event occurs, just call this method in the base class. The correct 'active' class will handle it then. The class itself can then check if it is not <code>Paused()</code>.

Better yet, use an event bus like <a href="https://github.com/greenrobot/EventBus" rel="nofollow noreferrer">GreenRobot's</a>, <a href="http://square.github.io/otto/" rel="nofollow noreferrer">Square's</a>, but that one is deprecated and suggests using <a href="http://blog.kaush.co/2014/12/24/implementing-an-event-bus-with-rxjava-rxbus/" rel="nofollow noreferrer">RxJava</a>

blocks|key|954007|text|ActivityLifecycleCallbacks是一种跟踪应用程序中所有活动的好方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|954008|public+class+BaseActivityLifecycleCallbacks+implements+Application.ActivityLifecycleCallbacks+{

private+ActivityState+homeState,+contentState;

@Override
public+void+onActivityCreated(Activity+activity,+Bundle+bundle)+{
++++if+(activity+instanceof+HomeActivityv2)+{
++++++++homeState+=+ActivityState.CREATED;
++++}+else+if+(activity+instanceof+ContentDisplayActivity)+{
++++++++contentState+=+ActivityState.CREATED;
++++}
}

@Override
public+void+onActivityStarted(Activity+activity)+{
++++if+(activity+instanceof+HomeActivityv2)+{
++++++++homeState+=+ActivityState.STARTED;
++++}+else+if+(activity+instanceof+ContentDisplayActivity)+{
++++++++contentState+=+ActivityState.STARTED;
++++}
}

@Override
public+void+onActivityResumed(Activity+activity)+{
++++if+(activity+instanceof+HomeActivityv2)+{
++++++++homeState+=+ActivityState.RESUMED;
++++}+else+if+(activity+instanceof+ContentDisplayActivity)+{
++++++++contentState+=+ActivityState.RESUMED;
++++}
}

@Override
public+void+onActivityPaused(Activity+activity)+{
++++if+(activity+instanceof+HomeActivityv2)+{
++++++++homeState+=+ActivityState.PAUSED;
++++}+else+if+(activity+instanceof+ContentDisplayActivity)+{
++++++++contentState+=+ActivityState.PAUSED;
++++}
}

@Override
public+void+onActivityStopped(Activity+activity)+{
++++if+(activity+instanceof+HomeActivityv2)+{
++++++++homeState+=+ActivityState.STOPPED;
++++}+else+if+(activity+instanceof+ContentDisplayActivity)+{
++++++++contentState+=+ActivityState.STOPPED;
++++}
}

@Override
public+void+onActivitySaveInstanceState(Activity+activity,+Bundle+bundle)+{
}

@Override
public+void+onActivityDestroyed(Activity+activity)+{
++++if+(activity+instanceof+HomeActivityv2)+{
++++++++homeState+=+ActivityState.DESTROYED;
++++}+else+if+(activity+instanceof+ContentDisplayActivity)+{
++++++++contentState+=+ActivityState.DESTROYED;
++++}
}

public+ActivityState+getHomeState()+{
++++return+homeState;
}

public+ActivityState+getContentState()+{
++++return+contentState;
}
}|code-block|syntax|javascript|954009|ActivityState：|954010|public+enum+ActivityState+{
++++CREATED,+STARTED,+RESUMED,+PAUSED,+STOPPED,+DESTROYED;
}|954011|扩展Application类并在Android+Manifest文件中提供其引用：|954012|import+android.app.Application;

public+final+class+BaseApplication+extends+Application+{
private+BaseActivityLifecycleCallbacks+baseALC;

@Override
public+void+onCreate()+{
++++super.onCreate();
++++baseALC+=+new+BaseActivityLifecycleCallbacks();
++++this.registerActivityLifecycleCallbacks(baseALC);

}

public+BaseActivityLifecycleCallbacks+getBaseALC()+{
++++return+baseALC;
}
}|954013|从活动的任何位置检查其他活动的状态：|954014|private+void+checkAndLaunchHomeScreen()+{
++++Application+application+=+getApplication();
++++if+(application+instanceof+BaseApplication)+{
++++++++BaseApplication+baseApplication+=+(BaseApplication)+application;
++++++++if+(baseApplication.getBaseALC().getHomeState()+==+null+%7C%7C+baseApplication.getBaseALC().getHomeState()+==+ActivityState.DESTROYED)+{
++++++++++++//Do+anything+you+want
++++++++}
++++}
}|954015|https://developer.android.com/reference/android/app/Application.ActivityLifecycleCallbacks.html|offset|length|954016|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|0|0|0|0|0|0|2N|0|0^^$0|@$1|2|3|4|5|6|7|13|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|14|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|15|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|16|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|17|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|18|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|19|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|1A|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|1B|8|@]|9|@$U|1C|V|1D|1|1E]]|A|$]]|$1|W|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|X|$Y|$5|Z|10|11|A|$12|T]]]]

ActivityLifecycleCallbacks is a great way of keeping track of all the activities in App:

<pre><code>public class BaseActivityLifecycleCallbacks implements Application.ActivityLifecycleCallbacks {

private ActivityState homeState, contentState;

@Override
public void onActivityCreated(Activity activity, Bundle bundle) {
 if (activity instanceof HomeActivityv2) {
 homeState = ActivityState.CREATED;
 } else if (activity instanceof ContentDisplayActivity) {
 contentState = ActivityState.CREATED;
 }
}

@Override
public void onActivityStarted(Activity activity) {
 if (activity instanceof HomeActivityv2) {
 homeState = ActivityState.STARTED;
 } else if (activity instanceof ContentDisplayActivity) {
 contentState = ActivityState.STARTED;
 }
}

@Override
public void onActivityResumed(Activity activity) {
 if (activity instanceof HomeActivityv2) {
 homeState = ActivityState.RESUMED;
 } else if (activity instanceof ContentDisplayActivity) {
 contentState = ActivityState.RESUMED;
 }
}

@Override
public void onActivityPaused(Activity activity) {
 if (activity instanceof HomeActivityv2) {
 homeState = ActivityState.PAUSED;
 } else if (activity instanceof ContentDisplayActivity) {
 contentState = ActivityState.PAUSED;
 }
}

@Override
public void onActivityStopped(Activity activity) {
 if (activity instanceof HomeActivityv2) {
 homeState = ActivityState.STOPPED;
 } else if (activity instanceof ContentDisplayActivity) {
 contentState = ActivityState.STOPPED;
 }
}

@Override
public void onActivitySaveInstanceState(Activity activity, Bundle bundle) {
}

@Override
public void onActivityDestroyed(Activity activity) {
 if (activity instanceof HomeActivityv2) {
 homeState = ActivityState.DESTROYED;
 } else if (activity instanceof ContentDisplayActivity) {
 contentState = ActivityState.DESTROYED;
 }
}

public ActivityState getHomeState() {
 return homeState;
}

public ActivityState getContentState() {
 return contentState;
}
}
</code></pre>

ActivityState:

<pre><code>public enum ActivityState {
 CREATED, STARTED, RESUMED, PAUSED, STOPPED, DESTROYED;
}
</code></pre>

Extend the Application class and provide its reference in Android Manifest file:

<pre><code>import android.app.Application;

public final class BaseApplication extends Application {
private BaseActivityLifecycleCallbacks baseALC;

@Override
public void onCreate() {
 super.onCreate();
 baseALC = new BaseActivityLifecycleCallbacks();
 this.registerActivityLifecycleCallbacks(baseALC);

}

public BaseActivityLifecycleCallbacks getBaseALC() {
 return baseALC;
}
}
</code></pre>

Ckeck anywhere from Activity for status of other activity:

<pre><code>private void checkAndLaunchHomeScreen() {
 Application application = getApplication();
 if (application instanceof BaseApplication) {
 BaseApplication baseApplication = (BaseApplication) application;
 if (baseApplication.getBaseALC().getHomeState() == null || baseApplication.getBaseALC().getHomeState() == ActivityState.DESTROYED) {
 //Do anything you want
 }
 }
}
</code></pre>

<a href="https://developer.android.com/reference/android/app/Application.ActivityLifecycleCallbacks.html" rel="nofollow noreferrer">https://developer.android.com/reference/android/app/Application.ActivityLifecycleCallbacks.html</a>

blocks|key|738088|text|那activity.isFinishing()呢？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|738089|entityMap^0|1|M|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

what about <code>activity.isFinishing()</code>

blocks|key|738184|text|如果你在前台没有相同的活动，这是可行的。如果你从通知中打开，不要工作，我做了一些调整，并附带了这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|738185|public+static+boolean+ativo+=+false;
public+static+int+counter+=+0;

@Override
protected+void+onCreate(Bundle+savedInstanceState)+{
++++super.onCreate(savedInstanceState);
++++...
++++counter%2B%2B;
}

@Override
protected+void+onStart()+{
++++super.onStart();
++++ativo+=+true;
}

@Override
protected+void+onStop()+{
++++super.onStop();
++++if+(counter==1)+ativo+=+false;
}

@Override
protected+void+onDestroy()+{
++++counter--;
++++super.onDestroy();
}|code-block|syntax|javascript|738186|这对于同时打开多个activitys的我来说是有效的。|738187|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

This work if you don't have the same activity in foreground.
If you open from notification don't work i made some adjustments and came with this:

<pre><code>public static boolean ativo = false;
public static int counter = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 ...
 counter++;
}

@Override
protected void onStart() {
 super.onStart();
 ativo = true;
}

@Override
protected void onStop() {
 super.onStop();
 if (counter==1) ativo = false;
}

@Override
protected void onDestroy() {
 counter--;
 super.onDestroy();
}
</code></pre>

That works for me with several activitys open at the same time.

blocks|key|954201|text|使用isActivity变量检查活动是否处于活动状态。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|954202|private+boolean+activityState+=+true;

+@Override
protected+void+onDestroy()+{
++++super.onDestroy();
++++activityState+=+false;
}|code-block|syntax|javascript|954203|然后勾选|954204|if(activityState){
//add+your+code
}|954205|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Use the isActivity variable to check if activity is alive or not.

<pre><code>private boolean activityState = true;

 @Override
protected void onDestroy() {
 super.onDestroy();
 activityState = false;
}
</code></pre>

Then check 

<pre><code>if(activityState){
//add your code
}
</code></pre>

blocks|key|738311|text|你试过..。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|738312|++++if+(getActivity()+instanceof+NameOfYourActivity){
++++++++//Do+something
++++}|code-block|syntax|javascript|738313|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Have you tried.. 

<pre><code> if (getActivity() instanceof NameOfYourActivity){
 //Do something
 }
</code></pre>

blocks|key|954345|text|我意识到这个问题已经很老了，但我认为它仍然值得分享我的解决方案，因为它可能对其他人有用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|954346|在Android架构组件发布之前，该解决方案不可用。|954347|活动至少部分可见|954348|getLifecycle().getCurrentState().isAtLeast(Lifecycle.State.STARTED)|code-block|syntax|javascript|954349|活动在前台|954350|getLifecycle().getCurrentState().isAtLeast(Lifecycle.State.RESUMED)|954351|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|S|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|T|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|H|7|V|8|@]|9|@]|A|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

I realize this issue is quite old, but I think it's still worth sharing my solution as it might be useful to others.
This solution wasn't available before Android Architecture Components were released.
Activity is at least partially visible
<pre><code>getLifecycle().getCurrentState().isAtLeast(Lifecycle.State.STARTED)
</code></pre>
Activity is in the foreground
<pre><code>getLifecycle().getCurrentState().isAtLeast(Lifecycle.State.RESUMED)
</code></pre>

blocks|key|738394|text|public+static+boolean+isActivityActive(Activity+activity)+{
+++if+(null+!=+activity)
++++++if+(Build.VERSION.SDK_INT+>=+Build.VERSION_CODES.JELLY_BEAN_MR1)
+++++++++return+!activity.isFinishing()+&&+!activity.isDestroyed();
++++++else+return+!activity.isFinishing();
+++return+false;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|738395|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>public static boolean isActivityActive(Activity activity) {
 if (null != activity)
 if (Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.JELLY_BEAN_MR1)
 return !activity.isFinishing() &amp;&amp; !activity.isDestroyed();
 else return !activity.isFinishing();
 return false;
}
</code></pre>

blocks|key|954414|text|我使用了task.topActivity而不是task.baseActivity，它对我来说工作得很好。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|954415|+++protected+Boolean+isNotificationActivityRunning()+{
++++ActivityManager+activityManager+=+(ActivityManager)+getBaseContext().getSystemService(Context.ACTIVITY_SERVICE);
++++List<ActivityManager.RunningTaskInfo>+tasks+=+activityManager.getRunningTasks(Integer.MAX_VALUE);

++++for+(ActivityManager.RunningTaskInfo+task+:+tasks)+{
++++++++if+(task.topActivity.getClassName().equals(NotificationsActivity.class.getCanonicalName()))
++++++++++++return+true;
++++}

++++return+false;
}|code-block|syntax|javascript|954416|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I have used task.topActivity instead of task.baseActivity and it works fine for me.
<pre><code> protected Boolean isNotificationActivityRunning() {
 ActivityManager activityManager = (ActivityManager) getBaseContext().getSystemService(Context.ACTIVITY_SERVICE);
 List&lt;ActivityManager.RunningTaskInfo&gt; tasks = activityManager.getRunningTasks(Integer.MAX_VALUE);

 for (ActivityManager.RunningTaskInfo task : tasks) {
 if (task.topActivity.getClassName().equals(NotificationsActivity.class.getCanonicalName()))
 return true;
 }

 return false;
}
</code></pre>

blocks|key|954484|text|我知道这个问题由来已久，有很多不同的答案，有各种优点和缺点。我对此的看法是，为什么不使用您自己的IPC实现。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|954485|class+IPC+{

++++companion+object+{
++++++++private+val+appContext+:+Context+by+lazy+{+/*genericApplicationContext*/+}

++++++++fun+initIPC(process:+String){
++++++++++++var+file+:+File?+=+null
++++++++++++file+=+File(appContext.cacheDir.absolutePath+%2B+"/$process")
++++++++++++var+output+:+OutputStream?+=+null
++++++++++++try+{
++++++++++++++++output+=+FileOutputStream(file!!)
++++++++++++++++output.write(0)
++++++++++++}+finally+{
++++++++++++++++output?.close()
++++++++++++}
++++++++}

++++++++fun+destroyIPC(process:+String){
++++++++++++var+file+:+File?+=+null
++++++++++++file+=+File(appContext.cacheDir.absolutePath+%2B+"/$process")
++++++++++++file.delete()
++++++++}

++++++++fun+checkForIPC(process:+String)+:+Boolean+{
++++++++++++var+file+:+File?+=+null
++++++++++++file+=+File(appContext.cacheDir.absolutePath+%2B+"/$process")
++++++++++++if(file.exists())+return+true
++++++++++++return+false
++++++++}
++++}

}|code-block|syntax|javascript|954486|这允许您在启动活动之前创建文件，然后在关闭启动的活动时关闭“进程/文件”。这允许您检入后台线程或当前活动(如果您的“进程活动”在后台)，以查看文件是否仍处于打开状态，表明该活动仍处于活动状态。在我的例子中，我连续调用一个外部API，但需要限制调用的速率，所以使用这个来确保一次只有一个活动在调用API。|954487|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I know this question is old and has a lot of varying answers, with various bonuses and drawbacks. My take on it, is why not roll your own IPC implementation.
<pre><code>class IPC {

 companion object {
 private val appContext : Context by lazy { /*genericApplicationContext*/ }

 fun initIPC(process: String){
 var file : File? = null
 file = File(appContext.cacheDir.absolutePath + &quot;/$process&quot;)
 var output : OutputStream? = null
 try {
 output = FileOutputStream(file!!)
 output.write(0)
 } finally {
 output?.close()
 }
 }

 fun destroyIPC(process: String){
 var file : File? = null
 file = File(appContext.cacheDir.absolutePath + &quot;/$process&quot;)
 file.delete()
 }

 fun checkForIPC(process: String) : Boolean {
 var file : File? = null
 file = File(appContext.cacheDir.absolutePath + &quot;/$process&quot;)
 if(file.exists()) return true
 return false
 }
 }

}
</code></pre>
This allows you to create the file before launching the activity, and then close out the &quot;process/file&quot; when you close the launched activity. This allows you to check in a background thread or current activity if your &quot;process activity&quot; is in the background to see if the file is still open signaling that the activity is alive. In my case I am calling an external API in succession but need to rate limit the calls, so use this to make sure only one activity is alive calling the APIs at a time.

Is there any simple way of determining whether or not a certain activity is active?
I want to do certain things depending on which activity is active.
eg: 

<pre><code>if(activityrunning == activity1)
//do this
else if (activityrunning == activity2)
//do something else
</code></pre>

Android: how do I check if activity is running?

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Android

有没有什么简单的方法来确定某个活动是否处于活动状态？我想根据哪个活动处于活动状态来执行某些操作。例如：if(activityrunning == activity1)//do thiselse if (activityrunning == activity2)//do something else

问Android:如何检查activity是否正在运行？
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