如何通过Firebase控制台给Unity应用发送带大图的推送通知？大图不显示

Got it, let's tackle that big image issue in your Unity Firebase push notifications. I've run into this exact problem before, so here's a step-by-step breakdown to get it working:

1. Double-Check Firebase Console Configuration #

First, make sure you're setting up the notification correctly in the Firebase Console—small mistakes here often cause the image to fail:

• Use Combined Notification + Data Messages: When sending from the console, don't just send a basic "Notification" message. Go to the Advanced options tab and add your custom data (e.g., image → your_public_image_url). This ensures the custom image data is passed to your Unity app, even when the app is in the background.
• Verify Image URL: The image must be a public, HTTPS-accessible URL (no local paths or HTTP URLs, as modern Android/iOS blocks insecure connections). Test the URL in your device's browser to confirm it loads properly. Aim for a reasonable size (e.g., 1024x512 pixels) to avoid loading timeouts.
• Set High Priority: In the console's Advanced options, set the message priority to High—this ensures the notification is delivered promptly and has enough resources to load the image.

2. Unity Client Code to Handle Big Images #

Firebase's Unity SDK doesn't automatically render big images from custom data—you need to write code to parse the data and build a styled notification manually. Here's how to do it for Android (iOS has extra steps below):

Step 2.1: Listen for Message Received Events #

First, set up a listener to catch incoming Firebase messages:

using Firebase.Messaging;
using UnityEngine;

public class FirebaseNotificationHandler : MonoBehaviour
{
    void Start()
    {
        FirebaseMessaging.MessageReceived += OnFirebaseMessageReceived;
    }

    void OnFirebaseMessageReceived(object sender, MessageReceivedEventArgs e)
    {
        Debug.Log("New Firebase message received!");
        
        // Extract notification content and custom data
        var notification = e.Message.Notification;
        var customData = e.Message.Data;

        // Get the big image URL from custom data
        string bigImageUrl = string.Empty;
        if (customData.TryGetValue("image", out string url))
        {
            bigImageUrl = url;
        }

        // Build and show the styled notification for Android
        #if UNITY_ANDROID && !UNITY_EDITOR
        ShowStyledAndroidNotification(notification.Title, notification.Body, bigImageUrl);
        #endif
    }
}

Step 2.2: Build a Big Picture Notification for Android #

You'll need to interact with Android's NotificationCompat library to create a big picture style notification. Note: Loading the remote image requires downloading it first—here's a simplified example (you'll need to add image download logic):

#if UNITY_ANDROID && !UNITY_EDITOR
private void ShowStyledAndroidNotification(string title, string body, string imageUrl)
{
    // Access Android context and notification tools
    AndroidJavaClass unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
    AndroidJavaObject currentActivity = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity");
    string packageName = currentActivity.Call<string>("getPackageName");

    // Create notification builder with your channel ID (must be created first!)
    AndroidJavaObject builder = new AndroidJavaObject(
        "androidx.core.app.NotificationCompat$Builder", 
        currentActivity, 
        "your_notification_channel_id"
    );

    // Set basic notification properties
    builder.Call<AndroidJavaObject>("setContentTitle", title)
           .Call<AndroidJavaObject>("setContentText", body)
           .Call<AndroidJavaObject>("setAutoCancel", true)
           .Call<AndroidJavaObject>("setSmallIcon", GetAndroidResourceId("ic_notification", "drawable"));

    // Add big picture style if image URL exists
    if (!string.IsNullOrEmpty(imageUrl))
    {
        // First, download the image to a Bitmap (use UnityWebRequest or Android's Glide/Picasso)
        // This is a placeholder—implement async image download here
        AndroidJavaObject bitmap = DownloadImageToBitmap(imageUrl);
        
        if (bitmap != null)
        {
            AndroidJavaObject bigPictureStyle = new AndroidJavaObject("androidx.core.app.NotificationCompat$BigPictureStyle");
            bigPictureStyle.Call<AndroidJavaObject>("bigPicture", bitmap);
            builder.Call<AndroidJavaObject>("setStyle", bigPictureStyle);
        }
    }

    // Show the notification
    AndroidJavaClass notificationManagerCompat = new AndroidJavaClass("androidx.core.app.NotificationManagerCompat");
    notificationManagerCompat.CallStatic("from", currentActivity)
                             .Call("notify", 1001, builder.Call<AndroidJavaObject>("build"));
}

private int GetAndroidResourceId(string resourceName, string resourceType)
{
    AndroidJavaClass unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
    AndroidJavaObject currentActivity = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity");
    return currentActivity.Call<int>("getResources")
                          .Call<AndroidJavaObject>("getIdentifier", resourceName, resourceType, currentActivity.Call<string>("getPackageName"))
                          .Call<int>("intValue");
}

// Implement this method to download the image and convert to Android Bitmap
private AndroidJavaObject DownloadImageToBitmap(string url)
{
    // Example using UnityWebRequest (simplified, should be async)
    using (var webRequest = UnityEngine.Networking.UnityWebRequestTexture.GetTexture(url))
    {
        var operation = webRequest.SendWebRequest();
        while (!operation.isDone) { }

        if (webRequest.result == UnityEngine.Networking.UnityWebRequest.Result.Success)
        {
            Texture2D texture = ((UnityEngine.Networking.DownloadHandlerTexture)webRequest.downloadHandler).texture;
            // Convert Texture2D to Android Bitmap (requires some JNI calls or a helper plugin)
            // For simplicity, you can use a plugin like Native Gallery or write custom JNI code here
            return ConvertTextureToBitmap(texture);
        }
    }
    return null;
}

private AndroidJavaObject ConvertTextureToBitmap(Texture2D texture)
{
    // Implement conversion logic here (JNI or helper method)
    // This is a placeholder—you'll need to fill this in based on your needs
    return null;
}
#endif

3. iOS-Specific Setup #

For iOS, big images require a Notification Service Extension to download and attach the image to the notification:

• In your Xcode project, add a new Notification Service Extension target.
• In the Firebase Console, add mutable-content: 1 to your custom data (this tells iOS to route the notification through your extension).
• In the extension's didReceiveNotificationRequest method, download the image from your custom image field, attach it to the notification content, and call contentHandler.

4. Common Troubleshooting Tips #

• Check Permissions: Ensure your Unity app has been granted notification permissions (request them at startup if needed).
• Update Firebase SDK: Make sure you're using the latest version of Firebase Messaging for Unity—older versions may have bugs with custom data handling.
• Test Background Delivery: If the app is in the background, ensure Android's battery optimization is disabled for your app, and iOS's Background App Refresh is enabled.
• Verify Channel ID: Android requires a valid notification channel—create one in your Unity code or Android manifest before showing notifications.

内容的提问来源于stack exchange，提问作者samson