解决Fail to post notification on channel "null"的方法

 

mnotifymgr = (notificationmanager) getsystemservice(notification_service);
mnotifymgr.cancelall();

string title = getstring(r.string.filtershow_notification_label);
        if(build.version.sdk_int >= build.version_codes.o) {
            string id = "channel_1";
            notificationchannel channel = new notificationchannel(id, title, notificationmanager.importance_high);
            mnotifymgr.createnotificationchannel(channel);
            mbuilder = new notification.builder(this, id)
                    .setcategory(notification.category_event)
                    .setsmallicon(r.drawable.filtershow_button_fx)
                    .setcontenttitle(title)
                    .setcontenttext(getstring(r.string.filtershow_notification_message))
                    .setautocancel(true);
        } else {
            mbuilder = new notification.builder(this)
                    .setsmallicon(r.drawable.filtershow_button_fx)
                    .setcontenttitle(title)
                    .setcontenttext(getstring(r.string.filtershow_notification_message));
        }

mnotifymgr.notify(mnotificationid, mbuilder.build());

mnotificationid为1的话,systemui下拉栏会存在对应的通知item(可以用来点击跳转),
如果是0的话,则不会出现.