我是Android和编程的新手，我正在创建一个可接收来自FCM消息的应用程序，而该应用程序在后台运行，因此，我添加了一个FirebaseMessagingService类，该类在onMessageReceived方法中接收通知，然后跟随google文档，但在应用程序处于前台状态时，通知仍然不起作用，我已按照每个步骤进行操作，由于日志对我没有帮助，并且我未收到任何错误预期，因此我无法弄清代码中的问题所在这个我不知道是否是问题的来源： 在GCM事件java.lang.NumberFormatException中解析时间戳时出错：s == null
这是我的MyFirebaseMessagingService类
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Intent;
import android.support.v4.app.NotificationCompat;
import android.support.v4.app.NotificationManagerCompat;
import com.app.muhammadgamal.swapy.R;
import com.google.firebase.messaging.RemoteMessage;
public class MyFirebaseMessagingService extends com.google.firebase.messaging.FirebaseMessagingService {
@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
super.onMessageReceived(remoteMessage);
String click_Action = remoteMessage.getNotification().getClickAction();
String messageTitle = remoteMessage.getNotification().getTitle();
String messageBody = remoteMessage.getNotification().getBody();
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this, getString(R.string.default_notification_channel_id))
.setSmallIcon(R.drawable.ic_main_logo)
.setContentTitle(messageTitle)
.setContentText(messageBody)
.setPriority(NotificationCompat.PRIORITY_DEFAULT);
Intent intent = new Intent(click_Action);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
mBuilder.setContentIntent(pendingIntent);
int mNotificationID = (int)System.currentTimeMillis();
NotificationManager manager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
manager.notify(mNotificationID,mBuilder.build());
}
}
和我的清单文件
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.app.muhammadgamal.swapy">
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_main_logo"
android:label="@string/app_name"
android:roundIcon="@drawable/ic_main_logo"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity
android:name=".Activities.SignInActivity"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Activities.SignUpActivity"
android:theme="@style/AppTheme.NoActionBar" />
<activity
android:name=".Activities.ProfileActivity"
android:theme="@style/AppTheme.NoActionBar" />
<activity
android:name=".Activities.NavDrawerActivity"
android:theme="@style/AppTheme.NoActionBar" />
<activity
android:name=".Activities.SwapCreationActivity"
android:theme="@style/AppTheme.NoActionBar" />
<activity android:name=".Activities.ReceivedSwapRequest">
<intent-filter>
<action android:name="com.app.muhammadgamal.swapy.Activities.ReceivedSwapRequest_NOTIFICATION_TASK"></action>
<category android:name="android.intent.category.DEFAULT"></category>
</intent-filter>
</activity>
<service
android:name=".Notifications.MyFirebaseMessagingService">
<intent-filter>
<action android:name="com.google.firebase.MESSAGING_EVENT"/>
</intent-filter>
</service>
</application>
</manifest>
和我的索引函数
'use strict'
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);
exports.sendNotification = functions.database.ref('/Notifications/{receiver_user_id}/{notification_id}')
.onWrite((data, context) =>
{
const receiver_user_id = context.params.receiver_user_id;
const notification_id = context.params.notification_id;
console.log('We have a notification to send to :' , receiver_user_id);
if (!data.after.val())
{
console.log('A notification has been deleted :' , notification_id);
return null;
}
const DeviceToken = admin.database().ref(`/Users/${receiver_user_id}/device_token`).once('value');
return DeviceToken.then(result =>
{
const token_id = result.val();
const payload =
{
notification:
{
title: "New Swap Request",
body: `you have a new Swap Request, Please Check.`,
click_action: "com.app.muhammadgamal.swapy.Activities.ReceivedSwapRequest_NOTIFICATION_TASK"
}
};
return admin.messaging().sendToDevice(token_id, payload)
.then(response =>
{
return console.log('This was a notification feature.');
});
});
});
答案 0 :(得分：1)
我发现了问题，这是因为我使用的是Android O，并且未设置通知的通道ID，如果要在Android 8.0或更高版本上接收该通知，这是必须的
这是解决方案代码
theory termination_problem
imports
Complex_Main
"HOL-Library.Finite_Map"
begin
datatype (plugins del: "size") t = A | B | C "(nat, t) fmap"
abbreviation "tcf ≡ (λ v::(nat × nat). (λ r::nat. snd v + r))"
interpretation tcf: comp_fun_commute tcf
proof
fix x y
show "tcf y ∘ tcf x = tcf x ∘ tcf y"
proof -
fix z
have "(tcf y ∘ tcf x) z = snd y + snd x + z" by auto
also have "(tcf x ∘ tcf y) z = snd y + snd x + z" by auto
ultimately have "(tcf y ∘ tcf x) z = (tcf x ∘ tcf y) z" by auto
then show "(tcf y ∘ tcf x) = (tcf x ∘ tcf y)" by auto
qed
qed
instantiation t :: size
begin
primrec t_size :: "t ⇒ nat" where
AR: "t_size A = 0" |
BR: "t_size B = 0" |
CR: "t_size (C x) =
(Suc 0) + ffold tcf 0 (fset_of_fmap (fmmap t_size x))"
definition size_t where
size_t_def: "size_t = t_size"
instance ..
end
lemma ffold_rec_exp:
assumes "k |∈| fmdom x"
and "ky = (k, the (fmlookup (fmmap t_size x) k))"
shows "ffold tcf 0 (fset_of_fmap (fmmap t_size x)) =
tcf ky (ffold tcf 0 ((fset_of_fmap (fmmap t_size x)) |-| {|ky|}))"
using assms tcf.ffold_rec by auto
lemma elem_le_ffold:
assumes "k |∈| fmdom x"
shows "t_size (the (fmlookup x k)) <
(Suc 0) + ffold tcf 0 (fset_of_fmap (fmmap t_size x))"
using ffold_rec_exp assms by auto
lemma measure_cond [intro]:
assumes "k |∈| fmdom x"
shows "size (the (fmlookup x k)) < size (C x)"
using assms elem_le_ffold size_t_def by auto
abbreviation
"supc f xs ys ≡
fmmap_keys
(λk x. if (k |∈| fmdom ys) then (f x (the (fmlookup ys k))) else A)
(fmfilter (λk. k |∈| fmdom ys) xs)"
fun sup_t (infixl "⊔" 65) where
"A ⊔ _ = A"
| "B ⊔ x = (if x = B then B else A)"
| "C xs ⊔ x = (case x of C ys ⇒ C (supc sup_t xs ys) | _ ⇒ A)"
(*Examples*)
abbreviation "list_1 ≡ fmap_of_list [(1::nat, B)]"
abbreviation "list_2 ≡ fmap_of_list [(1::nat, A), (2::nat, A)]"
value "(C list_1) ⊔ (C list_2)"
abbreviation "list_3 ≡ fmap_of_list [(1::nat, B), (3::nat, A)]"
abbreviation "list_4 ≡ fmap_of_list [(2::nat, A), (4::nat, B)]"
value "(C list_3) ⊔ (C list_4)"
abbreviation "list_5 ≡ fmap_of_list [(1::nat, B), (2::nat, B)]"
abbreviation "list_6 ≡ fmap_of_list [(2::nat, B), (4::nat, B)]"
value "(C list_5) ⊔ (C list_6)"
abbreviation "list_7 ≡
fmap_of_list [(1::nat, B), (2::nat, C list_5), (3::nat, A)]"
abbreviation "list_8 ≡ fmap_of_list [(2::nat, B), (4::nat, B)]"
value "(C list_7) ⊔ (C list_8)"
abbreviation "list_9 ≡
fmap_of_list [(1::nat, B), (2::nat, C list_5), (3::nat, A)]"
abbreviation "list_10 ≡ fmap_of_list [(2::nat, C list_6), (3::nat, B)]"
value "(C list_9) ⊔ (C list_10)"
end