Android: How to check application is Running or not

Question

I need to check by packageName - running application or not. Until v.21 I simply get list of running applications and dance. But now it not working - returns only one my app. I know that I need use "Statistics Usage", but can't find completely example for it.

I don't need all this analytics, I need one simple function

bool isRunning(String packageName)

How to implement it on new Android (>21) without dancing arround it?

upd. Answer of code4rox the best. All is OK, thanks!

I use this code for check rights:

import android.content.pm.PackageManager;
import android.content.pm.ApplicationInfo;
import android.app.AppOpsManager;
import android.util.Log;
import  android.provider.Settings;

try {
            PackageManager packageManager = getContext().getPackageManager();
            ApplicationInfo applicationInfo = packageManager.getApplicationInfo(getContext().getPackageName(), 0);
            AppOpsManager appOpsManager = (AppOpsManager) getContext().getSystemService(Context.APP_OPS_SERVICE);
            int mode = appOpsManager.checkOpNoThrow(AppOpsManager.OPSTR_GET_USAGE_STATS, applicationInfo.uid, applicationInfo.packageName);
            if (!(mode == AppOpsManager.MODE_ALLOWED)) {
                Intent intent = new Intent(Settings.ACTION_USAGE_ACCESS_SETTINGS);
                startActivity(intent);
            }
        } catch (PackageManager.NameNotFoundException e) {}

And this for check app:

import android.util.Log;
import android.app.usage.UsageStatsManager;
import android.app.usage.UsageStats;
import java.util.List;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.ArrayList;

public boolean isRunning(Context context, long timeMills, String app) {
        boolean result = false;
        //timeMils = 1000
        UsageStatsManager usm = (UsageStatsManager)context.getSystemService(Context.USAGE_STATS_SERVICE);
        long time = System.currentTimeMillis();
        List<UsageStats> appList = usm.queryUsageStats(UsageStatsManager.INTERVAL_DAILY,  time - timeMills, time);
        if (appList != null && appList.size() > 0) {
            for (UsageStats usageStats : appList) {
                String appname = usageStats.getPackageName();
                Log.i("DOM_LAUNCHER", "Running app: " + appname);
                if (app.equals(appname)) {
                    result = true;
                }
            }
        }
        return result;
    }

Answer 1

There is no any way to get the all running apps in API level (>21) for the security reasons.

BUT

You can access to app usage history and statistics with the time intervals: days, weeks, months, and years with UsageStatsManager

Here is official Docs Link

The Other Apps like clean master , ccleaner use this technic to get running apps.

Here is the Example to get apps list using UsageStatsManager

Note: You must give Usage Access Permission before use UsageStatsManager