How to resolve errors caused by a jar file imported in Android binding project

JJ Muller 0

Hi,

I have a existing jar file imported in my Xamarin Forms android project that communicates to a specific device. A new jar file has been supplied with new features to control/access the device, however I get some errors when I import the new jar file that I do not understand.

Once the binding project in built, it produces .cs files with the below errors.

I get this in Xamarin and in .Net Maui. This same jar file can be used in a java android application (Android Studio) and works fine.

SeverityCodeDescriptionFileSeverityCodeDescriptionFileErrorCS0260Missing partial modifier on declaration of type 'EMVHandler'; another partial declaration of this type exists\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Emv.IEMVHandler.csErrorCS0579Duplicate 'Register' attribute\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Emv.IEMVHandler.csErrorCS0102The type 'OpenFailEventArgs' already contains a definition for 'p0'\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Fingerprint.IFingerDeviceOpenListener.csErrorCS0102The type 'OpenFailEventArgs' already contains a definition for 'P0'\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Fingerprint.IFingerDeviceOpenListener.csErrorCS0102The type 'OpenSuccessEventArgs' already contains a definition for 'p0'\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Fingerprint.IFingerDeviceOpenListener.csErrorCS0102The type 'OpenSuccessEventArgs' already contains a definition for 'P0'\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Fingerprint.IFingerDeviceOpenListener.csErrorCS0111Type 'OpenFailEventArgs' already defines a member called 'OpenFailEventArgs' with the same parameter types\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Fingerprint.IFingerDeviceOpenListener.csErrorCS0102The type 'FailureEventArgs' already contains a definition for 'p0'\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Net.Wifi.ICredentialListener.csErrorCS0102The type 'FailureEventArgs' already contains a definition for 'P0'\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Net.Wifi.ICredentialListener.csErrorCS0111Type 'FailureEventArgs' already defines a member called 'FailureEventArgs' with the same parameter types\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Net.Wifi.ICredentialListener.csErrorCS0260Missing partial modifier on declaration of type 'QPbocHandler'; another partial declaration of this type exists\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Qpboc.IQPbocHandler.csErrorCS0579Duplicate 'global::Android.Runtime.Register' attribute\NewPosTechBinding\obj\Debug\net8.0-android\generated\src\Com.Pos.Device.Qpboc.QPbocHandler.cs

Leon Lu (Shanghai Wicresoft Co,.Ltd.) 75,431 Reputation points Microsoft Vendor

2024-08-26T07:14:49.5733333+00:00

Based on your error messages "Type 'FailureEventArgs' already defines a member called 'FailureEventArgs' with the same parameter"

There is some conflict between event types that come from more than one interface "listener" type Please edit Transforms\Metadata.xml and add an argsType attribute on either of the interfaces like this document Problem: Duplicate custom EventArgs types,

JJ Muller 0

Thank you for the response.

I tried this but nothing changes. MAUI does not create the Transform folder automatically so I added the folder and the XML files as from Xamarin. In the metadata.xml file I added the following (not sure if I done it correctly):

<attr path="/api/package[@name='com.pos.device.fingerprint']/
interface[@name='FingerDeviceOpenListener']/method[@name='openFail']" name="argsType">FingerDeviceOpenListenerOpenFailEventArgs</attr>

<attr path="/api/package[@name='com.pos.device.fingerprint']/
interface[@name='FingerDeviceOpenListener']/method[@name='openSuccess']" name="argsType">FingerDeviceOpenListenerOpenSuccessEventArgs</attr>

<attr path="/api/package[@name='com.pos.device.net.wifi']/
interface[@name='CredentialListener']/method[@name='onFailure']" name="argsType">CredentialListenerFailureEventArgs</attr>

I will try the same in Xamarin and advise.

JJ Muller 0

In Xamarin I added the following in the Metadata.xml file and managed to resolve the "Type 'FailureEventArgs' already defines a member called 'FailureEventArgs' with the same parameter" errors.

<attr path="/api/package[@name='com.pos.device.fingerprint']/
interface[@name='FingerDeviceOpenListener']/method[@name='openFail']" name="argsType">FingerDeviceOpenListenerOpenFailEventArgs</attr>

<attr path="/api/package[@name='com.pos.device.fingerprint']/
interface[@name='FingerDeviceOpenListener']/method[@name='openSuccess']" name="argsType">FingerDeviceOpenListenerOpenSuccessEventArgs</attr>

<attr path="/api/package[@name='com.pos.device.net.wifi']/
interface[@name='CredentialListener']/method[@name='onFailure']" name="argsType">CredentialListenerFailureEventArgs</attr>

Further to resolve "Missing partial modifier on declaration of type 'EMVHandler'; another partial declaration of this type exists" and "Missing partial modifier on declaration of type 'QPbocHandler'; another partial declaration of this type exists", I added the following in the Metadata.xml file (not sure if this is the correct way though):

<attr path="/api/package[@name='com.pos.device.emv']/interface[@name='IEMVHandler']"
    name="managedName">ObsoleteIEMVHandler</attr>

<attr path="/api/package[@name='com.pos.device.qpboc']/interface[@name='IQPbocHandler']"
    name="managedName">ObsoleteIQPbocHandler</attr>

The Xamarin project builds without any errors thus far.

Thank you for the guidance.

Leon Lu (Shanghai Wicresoft Co,.Ltd.) 75,431 Reputation points Microsoft Vendor

2024-08-28T08:01:49.2433333+00:00

You are welcome, do you have issues in the MAUI project?
JJ Muller 0 Reputation points

2024-08-29T08:54:15.8733333+00:00

Yes, I had the same issues in the MAUI project. I was not 100% sure how to create a binding project in MAUI, I read somewhere that it can be added as a normal class project but when I added the metadata.xml it still had errors. I then created a "Android Java Library Binding" project, added the jar and the changes in the metadata.xml. Now it build successfully but when I add the project reference to my main project, I get a new kind of error complaining about the target frameworks being different, however when I check the properties, it shows .NET 8.0 and net8.0 (is this not the same?)

Project 'TestBinding\TestBinding.csproj' targets 'net8.0-android'. It cannot be referenced by a project that targets '.NETCoreApp,Version=v8.0'.

Is a "Android Java Library Binding" project the correct way in MAUI?
JJ Muller 0 Reputation points

2024-08-29T09:03:48.9466667+00:00

The project reference is added for all application types and then also shows an exclamation at net8.0-ios, net8.0-maccatalyst and net8.0-windows10.0.19041.0
Leon Lu (Shanghai Wicresoft Co,.Ltd.) 75,431 Reputation points Microsoft Vendor

2024-08-30T06:52:05.9866667+00:00

As you said, it is working in Xamarin, you can refer to this document:Xamarin.Android binding project migration

You can migrate it to MAUI directly.

Try to remove other platforms. Just keep the android platform and rebuild your project, will you get the error?
JJ Muller 0 Reputation points

2024-09-04T05:36:46.2833333+00:00

Thank you. I will try this and advise.
JJ Muller 0 Reputation points

2024-09-25T13:32:04.0133333+00:00

Hi.

I have attempted now to create a binding project in Xamarin and then upgrade to MAUI but the upgrade assistant is showing many incidents. How do I go about to upgrade this to MAUI?

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