András Tóth‘s professional blog
banditoth.net

Hey there 👋, I’m banditoth a .NET MAUI developer from Hungary.
I write about software development with .NET technologies.

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Tag: xamarin error

  • Xamarin.iOS : “Failed to compile the generated registrar code” on Visual Studio for Mac

    This content has 3 years. Some of the information in this post may be out of date or no longer work. Please, read this page keeping its age in your mind.

    If you have recently upgraded your XCode version to 14.0, and installed the XCode command line tools too, you will probably notice some error messages when trying to run your Xamarin.Forms, or iOS application from Visual Studio for Mac.

    Error MT4109: Failed to compile the generated registrar code.
    

    What actually helped me, is this:
    Navigate to https://developer.apple.com/download/all/ and search for Command Line Tools for Xcode 13.4 and Xcode 13.4. Both downloads are big, the XCode itself around 10GB and the CL Tools are around 1GB, so definitely do not do this on metered connections.

    Once the downloads are ready, open the XCode.XP file with the Package Archiver, let it extract to downloads, then move it to Applications folder.

    After that, install CL tools. Follow the installer’s instructions.

    Boom, it’s solved. Issue reported at: https://github.com/xamarin/xamarin-macios/issues/15954

  • Xamarin.Forms: ‘MSBuild:UpdateDesignTimeXaml’ code generator crashed solution

    This content has 3 years. Some of the information in this post may be out of date or no longer work. Please, read this page keeping its age in your mind.

    If you are facing an issue after updating the Xamarin.Forms version in your project, with the following error:

    SOMEXAMLFILE.xaml: Error: The 'MSBuild:UpdateDesignTimeXaml' code generator crashed: Not connected
      at MonoDevelop.Core.Execution.RemoteProcessConnection.PostMessage (MonoDevelop.Core.Execution.BinaryMessage message, System.Threading.Tasks.TaskCompletionSource`1[TResult] cs, System.Boolean checkInitialized) [0x000c3] in /Users/builder/azdo/_work/2/s/main/src/core/MonoDevelop.Core/MonoDevelop.Core.Execution/RemoteProcessConnection.cs:438 
      at MonoDevelop.Core.Execution.RemoteProcessConnection.SendMessage (MonoDevelop.Core.Execution.BinaryMessage message) [0x00031] in /Users/builder/azdo/_work/2/s/main/src/core/MonoDevelop.Core/MonoDevelop.Core.Execution/RemoteProcessConnection.cs:385 
      at MonoDevelop.Projects.MSBuild.RemoteBuildEngineManager+<>c__DisplayClass20_0.<GetBuildEngine>b__5 () [0x00252] in /Users/builder/azdo/_work/2/s/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/RemoteBuildEngineManager.cs:323 
      at MonoDevelop.Projects.MSBuild.RemoteBuildEngineManager.GetBuildEngine (MonoDevelop.Core.Assemblies.TargetRuntime runtime, System.String minToolsVersion, System.String solutionFile, System.String group, System.Object buildSessionId, System.Boolean setBusy, System.Boolean allowBusy) [0x0036f] in /Users/builder/azdo/_work/2/s/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/RemoteBuildEngineManager.cs:273 
      at MonoDevelop.Projects.MSBuild.RemoteBuildEngineManager.GetRemoteProjectBuilder (System.String projectFile, System.String solutionFile, MonoDevelop.Core.Assemblies.TargetRuntime runtime, System.String minToolsVersion, System.Object buildSessionId, System.Boolean setBusy, System.Boolean allowBusy) [0x000df] in /Users/builder/azdo/_work/2/s/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/RemoteBuildEngineManager.cs:176 [...]
    

    Then clean your solution, and restart Visual Studio for Mac.

  • Xamarin Forms: White screen between page push and pop solved

    This content has 4 years. Some of the information in this post may be out of date or no longer work. Please, read this page keeping its age in your mind.

    If you are experiencing white screen when pushing to Navigation or Modal stack on Android, read on.

    I’m not sure is this a bug in Xamarin Forms or not, but I guess this is, because it comes only in certain scenarios, and not always.

    What is happening, how do you notice this error?

    You have got a NavigationPage. You are pushing a new page to the navigationstack, and the page is not getting rendered, only a blank white screen displays.

    If you are rotating the device, the page is getting rendered well.

    My environment was:
    Xamarin.Forms: 4.8 up to 5.0
    Device: Samsung Galaxy A12
    Visual Studio 2019 Professional with Xamarin.Android SDK 11.4.0.5

    Solution

    Always invoke the INavigation’s methods on the applications Main Thread. UI changes must go always on the UI thread of the application.

    Create a class which wraps the INavigation presented by your Views. It’s handy to store a reference in this class to the Applications Current MainPage’s INavigation instance, so try to build your code to supply the actual INavigation Instance every time to this class when the application’s mainpage is set.

    	public class NavigationDispatcher : INavigation
    	{
    		private INavigation _navigation;
    
    		public IReadOnlyList<Page> ModalStack => _navigation?.ModalStack;
    
    		public IReadOnlyList<Page> NavigationStack => _navigation?.NavigationStack;
    
    		private void SetNavigation(INavigation navigation)
    		{
    			_navigation = navigation;
    		}
    
    		public void InsertPageBefore(Page page, Page before)
    		{
    			_ = Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(() =>
    			  {
    				  _navigation.InsertPageBefore(page, before);
    			  });
    		}
    
    		public Task<Page> PopAsync()
    		{
    			return Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(async () =>
    			{
    				return await _navigation.PopAsync();
    			});
    		}
    
    		public Task<Page> PopAsync(bool animated)
    		{
    			return Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(async () =>
    			{
    				return await _navigation.PopAsync(animated);
    			});
    		}
    
    		public Task<Page> PopModalAsync()
    		{
    			return Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(async () =>
    			{
    				return await _navigation.PopModalAsync();
    			});
    		}
    
    		public Task<Page> PopModalAsync(bool animated)
    		{
    			return Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(async () =>
    			{
    				return await _navigation.PopModalAsync(animated);
    			});
    		}
    
    		public Task PopToRootAsync()
    		{
    			return Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(async () =>
    			{
    				await _navigation.PopToRootAsync();
    			});
    		}
    
    		public Task PopToRootAsync(bool animated)
    		{
    			return Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(async () =>
    			{
    				await _navigation.PopToRootAsync(animated);
    			});
    		}
    
    		public Task PushAsync(Page page)
    		{
    			return Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(async () =>
    			{
    				await _navigation.PushAsync(page);
    			});
    		}
    
    		public Task PushAsync(Page page, bool animated)
    		{
    			return Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(async () =>
    			{
    				await _navigation.PushAsync(page, animated);
    			});
    		}
    
    		public Task PushModalAsync(Page page)
    		{
    			return Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(async () =>
    			{
    				await _navigation.PushModalAsync(page);
    			});
    		}
    
    		public Task PushModalAsync(Page page, bool animated)
    		{
    			return Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(async () =>
    			{
    				await _navigation.PushModalAsync(page, animated);
    			});
    		}
    
    		public void RemovePage(Page page)
    		{
    			_ = Xamarin.Essentials.MainThread.InvokeOnMainThreadAsync(() =>
    			  {
    				  _navigation.RemovePage(page);
    			  });
    		}
    	}
    
    

    Remarks

    Consider a check for the current thread in the methods body.
    If they are being executed in the main thread, you won’t need to switch to the main again
    .

    Bug is reported on Github: https://github.com/xamarin/Xamarin.Forms/issues/11993

  • Xamarin.Android: R.java error APT2258 invalid symbol name fix

    This content has 4 years. Some of the information in this post may be out of date or no longer work. Please, read this page keeping its age in your mind.

    If you are facing this issue:

    R.java : error APT2258: invalid symbol name 'com.companyname.appname:drawable/xxxx'.
    

    You should check for your Resources folder, and look for files with name like a C# or Java keyword. For example: new, public, private, static, class, and so on.

    If you rename the file, it will solve your problem.

  • Xamarin.Android: Missing aapt.exe

    This content has 4 years. Some of the information in this post may be out of date or no longer work. Please, read this page keeping its age in your mind.

    When trying to deploy an application to simulator or device, Visual Studio gives the following error:

    Cannot find `aapt.exe`. Please install the Android SDK Build-Tools package with the `C:\Program Files (x86)\Android\android-sdk\tools\android.bat` program.
    

    To solve this problem you sould go to Visual Studio’s Tools then Android and select SDK Manager option.

    Navigate to this option

    It will give an error dialog, that the SDK tool files are corrupted. Click repair.

    Click on Repair

    The mentioned batch command in the error message is deprecated by the way.

    Microsoft Windows [Version 10.0.19042.804]
    (c) 2020 Microsoft Corporation. All rights reserved.
    
    C:\Users\banditoth>cd C:\Program Files (x86)\Android\android-sdk\tools\
    
    C:\Program Files (x86)\Android\android-sdk\tools>android.bat
    **************************************************************************
    The "android" command is deprecated.
    For manual SDK, AVD, and project management, please use Android Studio.
    For command-line tools, use tools\bin\sdkmanager.bat
    and tools\bin\avdmanager.bat
    **************************************************************************
    
    Invalid or unsupported command ""
    
    Supported commands are:
    android list target
    android list avd
    android list device
    android create avd
    android move avd
    android delete avd
    android list sdk
    android update sdk
    
    C:\Program Files (x86)\Android\android-sdk\tools>