截至2019年7月

Android compileSdkVersion 28, buildToolsVersion 28.0.3和firebase-messaging:19.0.1

经过许多小时的研究，通过所有其他StackOverflow问题和答案，并尝试无数过时的解决方案，这个解决方案设法在以下3个场景中显示通知:

—应用程序在前台: 通知是由我的MyFirebaseMessagingService类的onmessagerreceived方法接收的

应用程序已经被杀死(它不在后台运行) FCM自动将通知发送到通知托盘。当用户触摸通知时，应用程序通过调用manifest中有android.intent.category.LAUNCHER的活动来启动。你可以在onCreate()方法中使用getIntent(). getextras()来获取通知的数据部分。

- App is in background: the notification is sent to the notification tray automatically by FCM. When the user touches the notification the app is brought to the foreground by launching the activity that has android.intent.category.LAUNCHER in the manifest. As my app has launchMode="singleTop" in that activity, the onCreate() method is not called because one activity of the same class is already created, instead the onNewIntent() method of that class is called and you get the data part of the notification there by using intent.getExtras().

步骤: 1-如果你这样定义你的应用程序的主活动:

<activity
    android:name=".MainActivity"
    android:label="@string/app_name"
    android:largeHeap="true"
    android:screenOrientation="portrait"
    android:launchMode="singleTop">
    <intent-filter>
        <action android:name=".MainActivity" />
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
        <category android:name="android.intent.category.DEFAULT" />
    </intent-filter>
</activity>

2-在MainActivity.class的onCreate()方法中添加这些行

Intent i = getIntent();
Bundle extras = i.getExtras();
if (extras != null) {
    for (String key : extras.keySet()) {
        Object value = extras.get(key);
        Log.d(Application.APPTAG, "Extras received at onCreate:  Key: " + key + " Value: " + value);
    }
    String title = extras.getString("title");
    String message = extras.getString("body");
    if (message!=null && message.length()>0) {
        getIntent().removeExtra("body");
        showNotificationInADialog(title, message);
    }
}

和这些方法到同一个MainActivity.class:

@Override
public void onNewIntent(Intent intent){
    //called when a new intent for this class is created.
    // The main case is when the app was in background, a notification arrives to the tray, and the user touches the notification

    super.onNewIntent(intent);

    Log.d(Application.APPTAG, "onNewIntent - starting");
    Bundle extras = intent.getExtras();
    if (extras != null) {
        for (String key : extras.keySet()) {
            Object value = extras.get(key);
            Log.d(Application.APPTAG, "Extras received at onNewIntent:  Key: " + key + " Value: " + value);
        }
        String title = extras.getString("title");
        String message = extras.getString("body");
        if (message!=null && message.length()>0) {
            getIntent().removeExtra("body");
            showNotificationInADialog(title, message);
        }
    }
}


private void showNotificationInADialog(String title, String message) {

    // show a dialog with the provided title and message
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle(title);
    builder.setMessage(message);
    builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            dialog.cancel();
        }
    });
    AlertDialog alert = builder.create();
    alert.show();
}

3-像这样创建MyFirebase类:

package com.yourcompany.app;

import android.content.Intent;
import android.util.Log;

import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;

public class MyFirebaseMessagingService extends FirebaseMessagingService {


    public MyFirebaseMessagingService() {
        super();
    }

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {

        Log.d(Application.APPTAG, "myFirebaseMessagingService - onMessageReceived - message: " + remoteMessage);

        Intent dialogIntent = new Intent(this, NotificationActivity.class);
        dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        dialogIntent.putExtra("msg", remoteMessage);
        startActivity(dialogIntent);

    }

}

4-创建一个新类NotificationActivity.class，如下所示:

package com.yourcompany.app;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.util.Log;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.view.ContextThemeWrapper;

import com.google.firebase.messaging.RemoteMessage;

public class NotificationActivity extends AppCompatActivity {

private Activity context;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    context = this;
    Bundle extras = getIntent().getExtras();

    Log.d(Application.APPTAG, "NotificationActivity - onCreate - extras: " + extras);

    if (extras == null) {
        context.finish();
        return;
    }

    RemoteMessage msg = (RemoteMessage) extras.get("msg");

    if (msg == null) {
        context.finish();
        return;
    }

    RemoteMessage.Notification notification = msg.getNotification();

    if (notification == null) {
        context.finish();
        return;
    }

    String dialogMessage;
    try {
        dialogMessage = notification.getBody();
    } catch (Exception e){
        context.finish();
        return;
    }
    String dialogTitle = notification.getTitle();
    if (dialogTitle == null || dialogTitle.length() == 0) {
        dialogTitle = "";
    }

    AlertDialog.Builder builder = new AlertDialog.Builder(new ContextThemeWrapper(context, R.style.myDialog));
    builder.setTitle(dialogTitle);
    builder.setMessage(dialogMessage);
    builder.setPositiveButton(getResources().getString(R.string.accept), new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            dialog.cancel();
        }
    });
    AlertDialog alert = builder.create();
    alert.show();

}

}

5-添加这些行到你的应用程序清单，在你的标签

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

    <meta-data android:name="com.google.firebase.messaging.default_notification_channel_id" android:value="@string/default_notification_channel_id"/>

    <activity android:name=".NotificationActivity"
        android:theme="@style/myDialog"> </activity>

    <meta-data
        android:name="com.google.firebase.messaging.default_notification_icon"
        android:resource="@drawable/notification_icon"/>

    <meta-data
        android:name="com.google.firebase.messaging.default_notification_color"
        android:resource="@color/color_accent" />

6-在Application.java的onCreate()方法或MainActivity.class的onCreate()方法中添加这些行:

      // notifications channel creation
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
      // Create channel to show notifications.
      String channelId = getResources().getString("default_channel_id");
      String channelName = getResources().getString("General announcements");
      NotificationManager notificationManager = getSystemService(NotificationManager.class);
      notificationManager.createNotificationChannel(new NotificationChannel(channelId,
              channelName, NotificationManager.IMPORTANCE_LOW));
  }

完成了。

现在，为了在上述3个场景中很好地工作，你必须以以下方式从Firebase web控制台发送通知:

In the Notification section: Notification Title = Title to display in the notification dialog (optional) Notification text = Message to show to the user (required) Then in the Target section: App = your Android app and in Additional Options section: Android Notification Channel = default_channel_id Custom Data key: title value: (same text here than in the Title field of the Notification section) key: body value: (same text here than in the Message field of the Notification section) key:click_action value: .MainActivity Sound=Disabled Expires=4 weeks

你可以在模拟器中调试它与API 28谷歌播放。

编码快乐!

提供的解决方案对我的情况不起作用。

最后，我发现一些电池优化应用程序允许用户控制应用程序发送通知。在我的例子中，三星的Smart Manager在我的应用被从最近列表中删除后就自动阻止了它。

关闭我的应用程序的这个功能是我能找到的唯一解决办法。

2023年1月 对于那些实现了最新的Firebase云消息(FCM)的应用程序，您可能不会被限制在后台或完全关闭的情况下分别为应用程序发送数据和通知以处理数据。正如这里的一些回答所解释的那样，简短的版本是:

在你的启动器活动上，监视启动时的额外内容; 测试您的FCM数据中的唯一键是否在列表中; 如果存在，获取必要的数据并调用您的活动来处理您想要做的处理。

//Firebase
// [START handle_data_extras]
if (getIntent().getExtras() != null) {
    boolean fcmExtraFlag = false;
    for (String key : getIntent().getExtras().keySet()) {
        Object value = getIntent().getExtras().get(key);
        Log.d(TAG, "Key: " + key + " Value: " + value);
        if(key.equalsIgnoreCase("tracerId")){
            //test your known key to be sure it is from fcm
            //this must have come from notification (system) tray
            //this will come whether the app was in the background or completely off
            //generally, this could be in the main activity as it has the intent-filter already set
            fcmExtraFlag = true;
        }
    }
    //pick fcm values if present and notify and/or process accordingly
    //you may add time-lookup to ignore delayed (time-passed) ones; and ignore
    if(fcmExtraFlag){
        String tracerId = (String) getIntent().getExtras().get("tracerId"); 
        //prepare your data as needed
        String tracerData = tracerId+">"+data-one+">"+data-two;
        String msgBody = "This is a test notification; data received: "+tracerId;
        String fcmMessage = msgBody;
        //start your confirmation activity, directly or whichever way
        SidUtils.firebaseStartConfirms(msgBody, tracerData, this);
    }
}
// [END handle_data_extras]

如前所述，如果可能的话，这应该在你的主活动中，以处理你的应用程序实际上关闭的情况-而不仅仅是在后台。这些将通过点击系统托盘上的应用程序通知来触发。

我觉得所有的响应都是不完整的，但它们都有一些你需要处理的东西，当你的应用程序在后台时，一个有数据的通知。

遵循这些步骤，你将能够在应用程序处于后台时处理通知。

添加一个intent-filter，像这样: <活动android: name = "。MainActivity”> <意图过滤器> <行动android: name = "。MainActivity " / > <category android:name="android.intent.category. default " /> < /意图过滤器>

到要处理通知数据的活动。

以以下格式发送通知: ｛ “通知”:{ "click_action": "。MainActivity”, "body": "new Symulti update !"， "title": "新的Symulti更新!"， "icon": "ic_notif_symulti"}， "data":{…}， "to": "c9Vaa3ReGdk:APA91bH-AuXgg3lDN2WMcBrNhJZoFtYF9"}

这里的关键是加法

"click_action" : ".MainActivity"

其中. mainactivity是您在步骤1中添加的带有intent-filter的活动。

从.MainActivity的onCreate中的通知中获取数据信息: onCreate(Bundle savedInstanceState) super.onCreate (savedInstanceState); setContentView (R.layout.activity_main); //获取通知数据信息 Bundle Bundle = getIntent().getExtras(); If (bundle != null) { //bundle必须包含通知的"data"字段发送的所有信息 ｝ ｝

这就是你需要做的。

从服务器请求中完全删除通知有效负载。只发送数据并在onmessagerreceived()中处理它，否则当应用程序在后台或被杀死时，你的onmessagerreceived将不会被触发。

这是我从服务器发送的:

{
  "data":{
    "id": 1,
    "missedRequests": 5
    "addAnyDataHere": 123
  },
  "to": "fhiT7evmZk8:APA91bFJq7Tkly4BtLRXdYvqHno2vHCRkzpJT8QZy0TlIGs......"
}

你可以像这样在onMessageReceived(RemoteMessage message)中接收你的数据(假设我需要获取id)

Object obj = message.getData().get("id");
        if (obj != null) {
            int id = Integer.valueOf(obj.toString());
        }

类似地，你可以在onmessagerecreceived()内从服务器获得任何数据。

我也有同样的问题。经过一些挖掘为什么我的MainActivity被调用意图没有数据，我意识到我的发射器活动(如在Manifest)是SplashActivity。在那里我找到了消息数据，并将它们转发给MainActivity。效果很好。我相信这能帮助到一些人。

谢谢你的回答。