Android5.0以后获取当前activity的应用包名

ActivityManager activityManager = (ActivityManager)context.getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE);
ComponentName runningTopActivity = activityManager.getRunningTasks(1).get(0).topActivity;

public void getTopActivityPackageName(Context context) {
        final int PROCESS_STATE_TOP = 2;
        try {
            Field processStateField = ActivityManager.RunningAppProcessInfo.class.getDeclaredField("processState");
            List<ActivityManager.RunningAppProcessInfo> processes = ((ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE)).getRunningAppProcesses();
            for (ActivityManager.RunningAppProcessInfo process : processes) {
                if (process.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
                    int state = processStateField.getInt(process);
                    if (state == PROCESS_STATE_TOP) {
                        String[] packageName = process.pkgList;
                        return package[0];
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }   return "";
    }

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