getRunningTasks doesn't work in Android L

Question

In Android L, Google has disabled getRunningTasks. Now it can only return own apps task and the home launcher. I can no longer get other apps tasks. Our app needs that method to determine current top app. Any one has another method to do this?

I have searched in Google, no more topics about this except this: https://code.google.com/p/android-developer-preview/issues/detail?id=29

Answer 1

For a recent project that I worked on, I also need to detect when certain applications are launched. All my research lead to the getRunningTasks method, which is deprecated starting from Lollipop. However, to my surprises, I discovered that some of the app lock apps still work on lollipop devices, so they must have come up with a solution to get around this. So I dug a little deeper. Here is what I found out:

• 1. On pre-L devices, they still use getRunningTasks
• 2. On L devices, they use getRunningAppProcesses, which returns a list of processes currently running on the devices. You might think "well, that is not useful". Each processInfo has a attributed called importance. When an app becomes top activity, its processInfo importance also changes to IMPORTANCE_FOREGROUND. So you can filter out those processes that are not in foreground. From a each ProcessInfo, you can also ask a list of packages it loaded. You can then check if the list contains the same package that the app when are trying "protected".

Some sample code to detect when the default calendar app is launched:

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()]);
}
}

Note: getRunningAppProcesses is also intended for debugging or "building a user-facing process management UI". Not sure if google will close this backdoor the similar way they did to getRunningTasks.

So no, you can't get the topActivity anymore. But with a little bit hack you can achieve similar result.

Answer 2

As MKY mentioned, getRunningTasks() method does not work for getting the current application in Lollipop.

As sunxin8086 wrote, the one way for getting the running applications is by using getRunningAppsProcesses() method. However, the condition info.importance == IMPORTANCE_FOREGROUND can not determine the current app uniquely.

The better approach to determine the current foreground application may be checking the processState field in RunningAppProcessInfo object. This field is a hidden field, but you can see it in the RunningAppProcessInfo class. If this value is ActivityManager.PROCESS_STATE_TOP (which is also hidden static constant), the process is the current foreground process.

For example the code is

final int PROCESS_STATE_TOP = 2;
ActivityManager.RunningAppProcessInfo currentInfo = null;
Field field = null;
try {
    field = ActivityManager.RunningAppProcessInfo.class.getDeclaredField("processState");
} catch (Exception ignored) {
}
ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
List<ActivityManager.RunningAppProcessInfo> appList = am.getRunningAppProcesses();
for (ActivityManager.RunningAppProcessInfo app : appList) {
    if (app.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND 
            && app.importanceReasonCode == ActivityManager.RunningAppProcessInfo.REASON_UNKNOWN) {
        Integer state = null;
        try {
            state = field.getInt(app);
        } catch (Exception e) {
        }
        if (state != null && state == PROCESS_STATE_TOP) {
            currentInfo = app;
            break;
        }
    }
}
return currentInfo;

Note: processState field does not exist in pre-Lolipop. Please check that Build.VERSION.SDK_INT >= 21 before running the above code. The above code works only for Lollipop+.

The other approach, by Gaston (which is quite different), and the meaning of 'current application' is slightly different from this approach.

Please choose one for your purpose.

---

[EDIT]

As Sam pointed out, I modified START_TASK_TO_FRONT by PROCESS_STATE_TOP. (Both values are 2)

[EDIT2]

Sam has a new find! To determine the foreground application uniquely, one more condition

process.importanceReasonCode == 0

is necessary. The above code has been updated. Thanks!

Answer 3

Here's an exact solution to get current top activity on your Android L/Lollipop devices and Android M/Marshmallow devices.

First call this line of code:(One time)

Intent intent = new Intent(Settings.ACTION_USAGE_ACCESS_SETTINGS);
startActivity(intent);

The above code will open a screen named "Apps with usage access". Just check the radio button to on/true to allow usage access. Now call the following method in your service or anywhere you want:

public void getTopActivtyFromLolipopOnwards() {
    String topPackageName;
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        UsageStatsManager mUsageStatsManager = (UsageStatsManager) getSystemService(Context.USAGE_STATS_SERVICE);
        long time = System.currentTimeMillis();
        // We get usage stats for the last 10 seconds
        List < UsageStats > stats = mUsageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_DAILY, time - 1000 * 10, time);
        // Sort the stats by the last time used
        if (stats != null) {
            SortedMap < Long, UsageStats > mySortedMap = new TreeMap < Long, UsageStats > ();
            for (UsageStats usageStats: stats) {
                mySortedMap.put(usageStats.getLastTimeUsed(), usageStats);
            }
            if (mySortedMap != null && !mySortedMap.isEmpty()) {
                topPackageName = mySortedMap.get(mySortedMap.lastKey()).getPackageName();
                Log.e("TopPackage Name", topPackageName);
            }
        }
    }
}

add permission

<uses-permission android:name="android.permission.PACKAGE_USAGE_STATS"
     tools:ignore="ProtectedPermissions" />

This will return the package name of currently running activity , whether it is facebook or whatsapp.

The only complication of this method is you need to prompt user for allowing app usage stats ... i.e. the first step.

Hope! this helps everyone.

Answer 4

private String getProcess() throws Exception {
    if (Build.VERSION.SDK_INT >= 21) {
        return getProcessNew();
    } else {
        return getProcessOld();
    }
}

//API 21 and above
private String getProcessNew() throws Exception {
    String topPackageName = null;
    UsageStatsManager usage = (UsageStatsManager) context.getSystemService(Constant.USAGE_STATS_SERVICE);
    long time = System.currentTimeMillis();
    List<UsageStats> stats = usage.queryUsageStats(UsageStatsManager.INTERVAL_DAILY, time - ONE_SECOND * 10, time);
    if (stats != null) {
        SortedMap<Long, UsageStats> runningTask = new TreeMap<Long,UsageStats>();
        for (UsageStats usageStats : stats) {
            runningTask.put(usageStats.getLastTimeUsed(), usageStats);
        }
        if (runningTask.isEmpty()) {
            return null;
        }
        topPackageName =  runningTask.get(runningTask.lastKey()).getPackageName();
    }
    return topPackageName;
}

//API below 21
@SuppressWarnings("deprecation")
private String getProcessOld() throws Exception {
    String topPackageName = null;
    ActivityManager activity = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    List<RunningTaskInfo> runningTask = activity.getRunningTasks(1);
    if (runningTask != null) {
        RunningTaskInfo taskTop = runningTask.get(0);
        ComponentName componentTop = taskTop.topActivity;
        topPackageName = componentTop.getPackageName();
    }
    return topPackageName;
}

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