Android app nowgetting "requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified" crash

Question

I have a Visual Studio 2022 Xamarin Android app (I know it's now unsupported) that has worked fine for many years. It uses NuGet packages for Firebase, etc. After November 4 (probably the Firebase November 15 release), when the app is in the background and a notification comes in, it crashes with "FATAL EXCEPTION: Firebase-MyFirebaseMessagingService[AndroidRuntime] java.lang.IllegalArgumentException: requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent.[AndroidRuntime]". I do already use Flag_Immutable in my PendingIntent calls, and like I said, this always worked fine. Upon much investigation, I figure I have to upgrade from Xamarin to .NET8. I am trying that, but I am having issues as to which NuGet packages to use so as not to cause compatibility problems. The packages in question are: Newtonsoft.Json, FirebaseMessaging, Xamarin.Android.Support (probably now AndroidX?), Xamarin.Essentials, Xamarin.AndroidX.LegacySupport, and Xamarin.GooglePlayServices. Main questions are:

1. Is there a way to fix that error just within my current Xamarin project without having to migrate? I have tried many things, including adding AndroidX.Work.Runtime (which I can't because it's incomatible, etc.).
2. If I do have to migrate, is there a list of the best packages to use for .NET8?

Answer 1

If I do have to migrate, is there a list of the best packages to use for .NET8?

Firstly, you can read this MAUI support policy, check the different .NET version's end of support date.

Then you can migrate to the specific .NET version.

I create a .NET for android demo(.NET 9), And I install following nuget packages

Microsoft.Maui.Essentials 9.0.40   Newtonsoft.Json 13.0.3   Xamarin.AndroidX.Legacy.Support.Core.Utils 1.0.0.31 and Xamarin.AndroidX.Work.Runtime 2.10.0.3 Xamarin.Firebase.Messaging 124.1.0.1, No compatibility problems. By the way some of Xamarin.GooglePlayServices have been added in the Xamarin.Firebase.Messaging 124.1.0.1.

You can create a demo like us，then implement the basic function, if it works in your side. Then you can migrate to the .NET for android.

If you have .net for android or migrated issue, you could select .NET tag and then select .NET MAUI child tag.

Answer 2

The "requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified" crash in Android apps is a common issue that arises when targeting Android 12 (API level 31) and above. Here's a breakdown of the problem and how to fix it:

Understanding the Problem

• PendingIntents:
  • PendingIntents are used to grant another application the right to perform an action on your app's behalf.
    • They are commonly used in notifications, alarms, and widgets.
    • Mutability:
      • Android 12 introduced stricter requirements for PendingIntents regarding their mutability.
        • You must now explicitly declare whether a PendingIntent can be modified after it's created.
        • Flags:
          • FLAG_IMMUTABLE: Indicates that the PendingIntent cannot be modified. This is generally the preferred option for security reasons.
            • FLAG_MUTABLE: Indicates that the PendingIntent can be modified. Use this only when necessary, such as for inline replies or bubbles.
            • The Crash:
              • If your app targets Android 12 or higher and you create a PendingIntent without specifying either FLAG_IMMUTABLE or FLAG_MUTABLE, the system throws an IllegalArgumentException, causing a crash.

How to Fix It

Identify PendingIntent Creation:

• Locate the places in your code where you create PendingIntents (e.g., using PendingIntent.getActivity(), PendingIntent.getBroadcast(), PendingIntent.getService()).

Add Mutability Flags:

  Modify the PendingIntent creation code to include either `FLAG_IMMUTABLE` or `FLAG_MUTABLE` as a flag.
  
     **Recommended:** Use `FLAG_IMMUTABLE` whenever possible.
     
        Example:
        
              - **Before:** Java
              
              ```
              PendingIntent pendingIntent = PendingIntent.getBroadcast(context, requestCode, intent, 
              ```
              
                    - **After:** Java
                    
                    ```
                    PendingIntent pendingIntent = PendingIntent.getBroadcast(context, requestCode, intent, PendingIntent.FLAG_IMMUTABLE);
                    ```
                    
                    **When to Use FLAG_MUTABLE:**
                    
                       - Use `FLAG_MUTABLE` only if your app's functionality genuinely requires the PendingIntent to be modified.
                       
                          - Examples:
                          
                                - Inline replies in notifications.
                                
                                      - Bubbles.
                                      
                                      **Update Dependencies:**
                                      
                                         - Sometimes, third-party libraries (like Firebase SDKs) might create PendingIntents internally.
                                         
                                            - Ensure that you are using the latest versions of your dependencies to incorporate any necessary fixes.
                                            
                                            **Testing:**
                                            
                                               - Thoroughly test your app on Android 12 and later devices to verify that the crash is resolved.
                                               

Important Considerations

• Security: FLAG_IMMUTABLE enhances security by preventing other apps from tampering with your PendingIntents.
• Target SDK: This issue primarily affects apps targeting Android 12 (API level 31) and above. However, it's good practice to implement the fix regardless of your target SDK.

By following these steps, you can effectively resolve the "requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified" crash in your Android app.The "requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified" crash in Android apps is a common issue that arises when targeting Android 12 (API level 31) and above. Here's a breakdown of the problem and how to fix it:

Understanding the Problem

• PendingIntents:
  • PendingIntents are used to grant another application the right to perform an action on your app's behalf.
    • They are commonly used in notifications, alarms, and widgets.
    • Mutability:
      • Android 12 introduced stricter requirements for PendingIntents regarding their mutability.
        • You must now explicitly declare whether a PendingIntent can be modified after it's created.
        • Flags:
          • FLAG_IMMUTABLE: Indicates that the PendingIntent cannot be modified. This is generally the preferred option for security reasons.
            • FLAG_MUTABLE: Indicates that the PendingIntent can be modified. Use this only when necessary, such as for inline replies or bubbles.
            • The Crash:
              • If your app targets Android 12 or higher and you create a PendingIntent without specifying either FLAG_IMMUTABLE or FLAG_MUTABLE, the system throws an IllegalArgumentException, causing a crash.

How to Fix It

Identify PendingIntent Creation:

• Locate the places in your code where you create PendingIntents (e.g., using PendingIntent.getActivity(), PendingIntent.getBroadcast(), PendingIntent.getService()).

Add Mutability Flags:

  Modify the PendingIntent creation code to include either `FLAG_IMMUTABLE` or `FLAG_MUTABLE` as a flag.
  
     **Recommended:** Use `FLAG_IMMUTABLE` whenever possible.
     
        Example:
        
              - **Before:** Java
              
              ```
              PendingIntent pendingIntent = PendingIntent.getBroadcast(context, requestCode, intent, 
              ```
              
                    - **After:** Java
                    
                    ```
                    PendingIntent pendingIntent = PendingIntent.getBroadcast(context, requestCode, intent, PendingIntent.FLAG_IMMUTABLE);
                    ```
                    
                    **When to Use FLAG_MUTABLE:**
                    
                       - Use `FLAG_MUTABLE` only if your app's functionality genuinely requires the PendingIntent to be modified.
                       
                          - Examples: 
                          
                                - Inline replies in notifications.
                                
                                      - Bubbles.
                                      
                                      **Update Dependencies:**
                                      
                                         - Sometimes, third-party libraries (like Firebase SDKs) might create PendingIntents internally.
                                         
                                            - Ensure that you are using the latest versions of your dependencies to incorporate any necessary fixes.
                                            
                                            **Testing:**
                                            
                                               - Thoroughly test your app on Android 12 and later devices to verify that the crash is resolved.
                                               

Important Considerations

• Security: FLAG_IMMUTABLE enhances security by preventing other apps from tampering with your PendingIntents.
• Target SDK: This issue primarily affects apps targeting Android 12 (API level 31) and above. However, it's good practice to implement the fix regardless of your target SDK.

By following these steps, you can effectively resolve the "requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified" crash in your Android app.

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