android：如何检查应用程序是否在后台运行

Question

I am newbie to android. I have client server based application. Server keeps on sending the update notifications to client after every single minute and at client side my app receive those updates and display it using Toast. But now my problem is whenever my client app goes into the background server keeps on sending the update notifications and my client display it as if the application is in foreground. I am not getting how to check that application is running in background.

Answer 1

Update, see this first:

Checking if an Android application is running in the background

---

To check if your application is sent to background, you can call this code on onPause() on every activity in your application:

 /**
   * Checks if the application is being sent in the background (i.e behind
   * another application's Activity).
   * 
   * @param context the context
   * @return <code>true</code> if another application will be above this one.
   */
  public static boolean isApplicationSentToBackground(final Context context) {
    ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    List<RunningTaskInfo> tasks = am.getRunningTasks(1);
    if (!tasks.isEmpty()) {
      ComponentName topActivity = tasks.get(0).topActivity;
      if (!topActivity.getPackageName().equals(context.getPackageName())) {
        return true;
      }
    }

    return false;
  }

For this to work you should include this in your AndroidManifest.xml

<uses-permission android:name="android.permission.GET_TASKS" />

Answer 2

http://developer.android.com/guide/topics/fundamentals.html#lcycles is a description of the Life Cycle of an android application.

The method onPause() gets called when the activity goes into the background. So you can deactivate the update notifications in this method.

Answer 3

Only for API level 14 and above

You can use ComponentCallbacks2 to an activity , service , etc.

Example:

public class MainActivity extends AppCompatActivity implements ComponentCallbacks2 {
   @Override
   public void onConfigurationChanged(final Configuration newConfig) {

   }

   @Override
   public void onLowMemory() {

   }

   @Override
   public void onTrimMemory(final int level) {
     if (level == ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN) {
        // app is in background
     }
   }
}

Answer 4

您可以在ActivityManager中使用getRunningAppProcesses（） 。