我的解决方案是添加：FCM_PLUGIN_ACTIVITY操作到AndroidManifest.xml

<activity
        ...
        android:name="com.appname.MainActivity"
        ...>

        ...
        ...
        ...

        <intent-filter>
            <action android:name="FCM_PLUGIN_ACTIVITY" />
            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>

此外，在服务器上，您应该在推送通知对象中包含该操作：

const pushNotification = {
  data: {
    ...
  },
  notification: {
    body: body,
    title: title,
    click_action: 'FCM_PLUGIN_ACTIVITY',
  },
};

在你的ionic项目中，你可以像下面这样处理pushNotificationActionPerformed，然后导航到所需的路由：

PushNotifications.addListener('pushNotificationActionPerformed',
  (notification: PushNotificationActionPerformed) => {
    console.log('Push action performed: ' + JSON.stringify(notification));
  }
);

要在应用打开时处理接收推送通知，您需要处理pushNotificationReceived，并在需要时自己显示一个吐司。

// the app is open, show your own notification if needed
PushNotifications.addListener('pushNotificationReceived',
  (notification: PushNotification) => {
    console.log('push notification received: ' + JSON.stringify(notification));
  }
);

我遇到了同样的问题，并在AndroidManifest.xml中使用以下行修复了它

<meta-data android:name="com.google.firebase.messaging.default_notification_channel_id" android:value="@string/default_notification_channel_id" />
<service android:name="com.getcapacitor.CapacitorFirebaseMessagingService" android:exported="false"> <intent-filter> <action android:name="com.google.firebase.MESSAGING_EVENT" /> </intent-filter> </service>

对于我们来说，如果我们另外安装了FCM插件（https://github.com/capacitor-community/fcm），我们需要iOS的后台通知（即使在应用程序被杀死后）也可以工作。

我有同样的问题.这是如何发送消息的技术基础.这里是一个PHP函数，从服务器发送通知到设备.“数据”是消息发送到应用程序，“通知”被发送到Android操作系统.

function sendGCM($message, $id) {

    $url = 'https://fcm.googleapis.com/fcm/send';

    $fields = array (
            'registration_ids' => array (
                    $id // The device token
            ),
            'data' => array (
                    "message" => $message
            ),
            // After I put "notification", the device started to receive notifications in the background:
            'notification' => array (
                "title" => "App Title Notification",
                "body" => $message
            )
    );
    $fields = json_encode ( $fields );

    $headers = array (
            'Authorization: key=' . "MY_API_Cloud_Messaging_KEY", // App Key from console.firebase.google.com
            'Content-Type: application/json'
    );

    $ch = curl_init ();
    curl_setopt ( $ch, CURLOPT_URL, $url );
    curl_setopt ( $ch, CURLOPT_POST, true );
    curl_setopt ( $ch, CURLOPT_HTTPHEADER, $headers );
    curl_setopt ( $ch, CURLOPT_RETURNTRANSFER, true );
    curl_setopt ( $ch, CURLOPT_POSTFIELDS, $fields );

    $result = curl_exec ( $ch );
    echo $result;
    curl_close ( $ch );

}