Android判断应用在前台还是后台运行(判断应用前后台切换)

Posted 2022-11-15 wulianghuan

这篇主要是针对android Lollipop 5.0 获取后台运行的APP包名，与低版本的区别说明。

我们的应用要获取后台运行的app的包名，主要是getRunningTasks()方法的调用，经过测试在android 2.2 到 4.4的版本都运行的很好，但是在Android 5.0 Lollipop. 中获得不到，无法得到真实的后台运行app名称，在Android 5.0 Lollipop中获得的名称是 'Launcher3'，我使用过的模拟器是  Genymotion Emulator。

下面是运行时的代码：

ActivityManager am = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
RunningTaskInfo foregroundTaskInfo = am.getRunningTasks(1).get(0);
String foregroundTaskPackageName = foregroundTaskInfo.topActivity  .getPackageName();

原因是Android 5.0在API权限上作了修改：

Android L, Google has disabled getRunningTasks. Now it can only return own apps task and the home launcher.

处理方法

参考文档：http://stackoverflow.com/questions/24625936/getrunningtasks-doesnt-work-in-android-l

public class DetectCalendarLaunchRunnable implements Runnable 

@Override
public void run() 
  String[] activePackages;
  if (Build.VERSION.SDK_INT > Build.VERSION_CODES.KITKAT_WATCH) 
    activePackages = getActivePackages();
   else 
    activePackages = getActivePackagesCompat();
  
  if (activePackages != null) 
    for (String activePackage : activePackages) 
      if (activePackage.equals("com.google.android.calendar")) 
        //Calendar app is launched, do something
      
    
  
  mHandler.postDelayed(this, 1000);


String[] getActivePackagesCompat() 
  final List<ActivityManager.RunningTaskInfo> taskInfo = mActivityManager.getRunningTasks(1);
  final ComponentName componentName = taskInfo.get(0).topActivity;
  final String[] activePackages = new String[1];
  activePackages[0] = componentName.getPackageName();
  return activePackages;


String[] getActivePackages() 
  final Set<String> activePackages = new HashSet<String>();
  final List<ActivityManager.RunningAppProcessInfo> processInfos = mActivityManager.getRunningAppProcesses();
  for (ActivityManager.RunningAppProcessInfo processInfo : processInfos) 
    if (processInfo.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) 
      activePackages.addAll(Arrays.asList(processInfo.pkgList));
    
  
  return activePackages.toArray(new String[activePackages.size()]);

通过上面的方法，获取到当前运行的程序packageName，与自己的packageName比对，

可以判断app是在前台还是后台运行，判断APP是否前台切换到后台等。