Android FCM - Disable/Enable Notifications

Question

I implemented like this:

public static void setPushSetting(Context context, boolean flag) {
    if(flag) {
        FirebaseInstanceId.getInstance().getToken();
    } else {
        try {
            FirebaseInstanceId.getInstance().deleteInstanceId();
        } catch (IOException e) {
            RxBus.getInstance().post(new OffPushError());
            e.printStackTrace();
        }
    }
}

Yesterday, it worked, but today FirebaseInstanceId.getInstance().deleteInstanceId(); always throws an exception.

Are there any other way to implement on disabling & enabling Firebase Push Notifications? Thanks for your help!
-------Update exception's log-------------

java.io.IOException: MAIN_THREAD
                                                            at com.google.firebase.iid.zzd.zzb(Unknown Source)
                                                            at com.google.firebase.iid.FirebaseInstanceId.deleteInstanceId(Unknown Source)
                                                            at jp.seesaa.itmama.push.PushUtil.setPushSetting(PushUtil.java:32)
                                                            at jp.seesaa.itmama.ui.main.setting.SettingFragment.onSharedPreferenceChanged(SettingFragment.java:66)
                                                            at android.app.SharedPreferencesImpl$EditorImpl.notifyListeners(SharedPreferencesImpl.java:476)
                                                            at android.app.SharedPreferencesImpl$EditorImpl.apply(SharedPreferencesImpl.java:384)
                                                            at android.support.v4.content.EditorCompatGingerbread.apply(EditorCompatGingerbread.java:25)
                                                            at android.support.v4.content.SharedPreferencesCompat$EditorCompat$EditorHelperApi9Impl.apply(SharedPreferencesCompat.java:45)
                                                            at android.support.v4.content.SharedPreferencesCompat$EditorCompat.apply(SharedPreferencesCompat.java:67)
                                                            at android.support.v7.preference.Preference.tryCommit(Preference.java:1353)
                                                            at android.support.v7.preference.Preference.persistBoolean(Preference.java:1558)
                                                            at android.support.v7.preference.TwoStatePreference.setChecked(TwoStatePreference.java:79)
                                                            at android.support.v7.preference.TwoStatePreference.onClick(TwoStatePreference.java:64)
                                                            at android.support.v7.preference.Preference.performClick(Preference.java:971)
                                                            at android.support.v7.preference.Preference.performClick(Preference.java:957)
                                                            at android.support.v7.preference.SwitchPreferenceCompat.performClick(SwitchPreferenceCompat.java:203)
                                                            at android.support.v7.preference.Preference$1.onClick(Preference.java:145)
                                                            at android.view.View.performClick(View.java:4780)
                                                            at android.view.View$PerformClick.run(View.java:19866)
                                                            at android.os.Handler.handleCallback(Handler.java:739)
                                                            at android.os.Handler.dispatchMessage(Handler.java:95)
                                                            at android.os.Looper.loop(Looper.java:135)
                                                            at android.app.ActivityThread.main(ActivityThread.java:5254)
                                                            at java.lang.reflect.Method.invoke(Native Method)
                                                            at java.lang.reflect.Method.invoke(Method.java:372)
                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

Answer 1

I fixed it by running via other thread like this:

Thread thread = new Thread(() -> {
                try {
                    FirebaseInstanceId.getInstance().deleteInstanceId();
                } catch (Exception e) {
                    Log.e("ERROR", Log.getStackTraceString(e) );
                    RxBus.getInstance().post(new OffPushError());
                }
        });
thread.start();