为什么我的onMessageReceived在FirebaseMessagingService中无法运行

Question

我正在尝试创建一个应用程序接收通知表单Firebase Cloud Messaging。但这不起作用：

似乎onMessageReceived无法运行，当我将其从Firebase发送到应用程序时，我尝试编写日志以查看消息，但是我什么也看不到。这是我的代码：

我的MyFirebaseMessagingService类：

public class MyFirebaseMessagingService extends FirebaseMessagingService {
    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        //super.onMessageReceived(remoteMessage);
        Log.d("From: " , remoteMessage.getFrom());
        if(remoteMessage.getNotification() != null){
            String title = remoteMessage.getNotification().getTitle();
            String body = remoteMessage.getNotification().getBody();
            Log.d("title: ", title);
            Log.d("body: ", body);
            sendNotification(title,body);

        }

    }

    @Override
    public void onNewToken(String s) {
        Log.d("NewToken: ",s);

        sendRegistrationToSever(s);
    }

    private void handleNow(){

    }
    private void sendRegistrationToSever(String token){

    }

    private void sendNotification(String title, String body){
        String channelId = getString(R.string.defaul_notification_channel_id);
        Intent intent = new Intent(this, MainActivity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

        PendingIntent pendingIntent = (PendingIntent) PendingIntent.getActivities(this, 0, new Intent[]{intent}, PendingIntent.FLAG_ONE_SHOT);

        Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);

        NotificationCompat.Builder builder = new NotificationCompat.Builder(this, channelId)
                .setSmallIcon(R.drawable.ic_launcher_foreground)
                .setContentTitle(title)
                .setContentText(body)
                .setAutoCancel(true)
                .setSound(defaultSoundUri)
                .setContentIntent(pendingIntent);

        NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel notificationChannel = new NotificationChannel(channelId,"Firebase Noti", NotificationManager.IMPORTANCE_DEFAULT);
            notificationManager.createNotificationChannel(notificationChannel);

        }
        notificationManager.notify(0, builder.build());
    }
}

我的清单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="dfk.example.com.firebasenotificationtry3">
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE"/>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service android:name=".Service.MyFirebaseMessagingService"
            android:exported="false">
            <intent-filter>
                <action android:name="com.google.firebase.MESSAGING_EVENT" />
            </intent-filter>
        </service>
    </application>

</manifest>

apply plugin: 'com.android.application'
apply plugin: 'com.google.gms.google-services'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "dfk.example.com.firebasenotificationtry3"
        minSdkVersion 16
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    //noinspection GradleCompatible
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    implementation 'com.google.firebase:firebase-messaging:18.0.0'
    implementation 'com.google.firebase:firebase-core:16.0.1'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
}

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        google()
        jcenter()

    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.3.2'
        classpath 'com.google.gms:google-services:4.1.0'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()

    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}