Android 4.1: How to check notifications are disabled for the application?

You can't 100% can't.

It is asked in this Google I/O 2012 video and the Project lead for the new notifications declares that you can't.

Edit

2016 update: Now you can check it, as said in this Google I/O 2016 video.

Use NotificationManagerCompat.areNotificationsEnabled(), from support library, to check if notifications are blocked on API 19+. The versions below API 19 will return true (notifications are enabled).

Answer from @blundell is correct but there is a minor change in newer versions.

NotificationManagerCompat.from(context).areNotificationsEnabled()

Actually this is pretty easy to do:

/**
 * Created by desgraci on 5/7/15.
*/
public class NotificationsUtils {

    private static final String CHECK_OP_NO_THROW = "checkOpNoThrow";
    private static final String OP_POST_NOTIFICATION = "OP_POST_NOTIFICATION";

    public static boolean isNotificationEnabled(Context context) {

        AppOpsManager mAppOps = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);

        ApplicationInfo appInfo = context.getApplicationInfo();

        String pkg = context.getApplicationContext().getPackageName();

        int uid = appInfo.uid;

        Class appOpsClass = null; /* Context.APP_OPS_MANAGER */

        try {

            appOpsClass = Class.forName(AppOpsManager.class.getName());

            Method checkOpNoThrowMethod = appOpsClass.getMethod(CHECK_OP_NO_THROW, Integer.TYPE, Integer.TYPE, String.class);

            Field opPostNotificationValue = appOpsClass.getDeclaredField(OP_POST_NOTIFICATION);
            int value = (int)opPostNotificationValue.get(Integer.class);

            return ((int)checkOpNoThrowMethod.invoke(mAppOps,value, uid, pkg) == AppOpsManager.MODE_ALLOWED);

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (NoSuchFieldException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return false;
    }
}

If you are using Xamarin and you need this answer you can use this code:

//return true if this option is not supported.
public class NotificationsUtils 
{
    private const String CHECK_OP_NO_THROW = "checkOpNoThrow";
    private const String OP_POST_NOTIFICATION = "OP_POST_NOTIFICATION";

    public static bool IsNotificationEnabled(global::Android.Content.Context context) {

        AppOpsManager mAppOps = (AppOpsManager) context.GetSystemService(global::Android.Content.Context.AppOpsService);

        ApplicationInfo appInfo = context.ApplicationInfo;

        String pkg = context.ApplicationContext.PackageName;

        int uid = appInfo.Uid;

        try {

            var appOpsClass = Java.Lang.Class.ForName("android.app.AppOpsManager");
            var checkOpNoThrowMethod = appOpsClass.GetMethod(CHECK_OP_NO_THROW,Java.Lang.Integer.Type,Java.Lang.Integer.Type,new Java.Lang.String().Class);//need to add String.Type

            var opPostNotificationValue = appOpsClass.GetDeclaredField (OP_POST_NOTIFICATION);
            var value = (int)opPostNotificationValue.GetInt(Java.Lang.Integer.Type);
            var mode = (int)checkOpNoThrowMethod.Invoke(mAppOps,value, uid, pkg);
            return (mode == (int)AppOpsManagerMode.Allowed);

        } catch (Exception) 
        {
            System.Diagnostics.Debug.WriteLine  ("Notification services is off or not supported");
        } 
        return true;
    }
}

It seems like there is no way to query notification state.

I recommend this:

• Design you application with notifications.
• Let user to disable notifications from application's settings.
• Check whether notifications are clicked. If user clicks notification, save this to preferences.
• In your app, if notification setting is on, and if user is Android 4.1+ (API 16), but if user doesn't click notification for some days / weeks, assume that user disabled notifications.

Not 100% correct. But this gives an opinion.
For example if user doesn't click any app notification for 10-15 days, probably he disabled it