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[Bug] TapGestureRecognizer Tapped event gets triggered incorrectly on Spans when text in the span is multiline #15378

Open Kas-code opened 2 years ago

Kas-code commented 2 years ago

Description

If a span in the configuration below happens to break a line, then its TapGestureRecognizer will get triggered incorrectly when I am tapping on other spans. The exact issue is easier to explain with the aid of the screenshot at the end of the post.

Steps to Reproduce

  1. AboutPage.xaml: 
<ScrollView>
    <StackLayout Padding="10">
        <Label FontSize="Large">
            <Label.FormattedText>
                <FormattedString x:Name="FormattedString">
                </FormattedString>
             </Label.FormattedText>
          </Label>
      </StackLayout>
</ScrollView>

  1. AboutPage.xaml.cs:

    public partial class AboutPage : ContentPage
{
    private static string text = @"abcdefghijklmnopabcdefghijklmnopabcdefghijklmnopabcdefghijklmnopabcdefghijklmnopabcdefghijklmnopabcdefghijklmnopabcdefghijklmnopabcdefghijklmnopabcdefghijklmnopabcdefghijklmnopabcdefghijklmnop";

    public AboutPage()
    {
        InitializeComponent();

        var charGroupLength = 3;
        var colour = 0;

        for (var i = 0; i < text.Length - charGroupLength; i += charGroupLength)
        {
            AddSpanForChars(text.Substring(i, charGroupLength), colour);
            colour++;
        }
    }

    private void AddSpanForChars(string word, int colour)
    {
        var s = new Span();

        switch (colour%3)
        {
            case 0:
                s.BackgroundColor = Color.Red;
                break;

            case 1:
                s.BackgroundColor = Color.Green;
                break;

            case 2:
                s.BackgroundColor = Color.Blue;
                break;
        }

        s.Text = word;

        FormattedString.Spans.Add(s);

        var onTapped = new TapGestureRecognizer();
        onTapped.Tapped += (sender, e) => OnTapped(sender, e, word);

        s.GestureRecognizers.Add(onTapped);
    }

    private void OnTapped(object Sender, EventArgs e, string word)
    {
        DisplayAlert("Tapped", word, "OK");
    }
}

    Expected Behavior

The alert is only displayed for words that you tap on

Actual Behavior

If a span breaks a line, then clicking any span on that line triggers the TapGestureRecognizer for the span tapped on (which should happen) but also the TapGestureRecognizer for the line-breaking span at the end of the line gets triggered (which shouldn't happen because it wasn't tapped)

Basic Information

Environment

Show/Hide Visual Studio info ``` Microsoft Visual Studio Community 2019 Version 16.11.10 VisualStudio.16.Release/16.11.10+32126.315 Microsoft .NET Framework Version 4.8.04084 Installed Version: Community ASP.NET and Web Tools 2019 16.11.106.23128 ASP.NET and Web Tools 2019 ASP.NET Web Frameworks and Tools 2019 16.11.106.23128 For additional information, visit https://www.asp.net/ Azure App Service Tools v3.0.0 16.11.106.23128 Azure App Service Tools v3.0.0 Azure Functions and Web Jobs Tools 16.11.106.23128 Azure Functions and Web Jobs Tools C# Tools 3.11.0-4.21602.3+fc14a1355c0461af5110b74b26f6478f22d26565 C# components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used. CodeMaid 12.0.300 CodeMaid is an open source Visual Studio extension to cleanup and simplify our C#, C++, F#, VB, PHP, PowerShell, R, JSON, XAML, XML, ASP, HTML, CSS, LESS, SCSS, JavaScript and TypeScript coding. Common Azure Tools 1.10 Provides common services for use by Azure Mobile Services and Microsoft Azure Tools. Extensibility Message Bus 1.2.6 (master@34d6af2) Provides common messaging-based MEF services for loosely coupled Visual Studio extension components communication and integration. FormatDocumentOnSave 1.0 Enables auto formatting of the code when you save a file. Visual Studio supports auto formatting of the code with the CTRL+E,D or CTRL+E,F key shortcuts but with this extension the command 'Format Document' is executed on Save. You can find the source here: https://github.com/Elders/VSE-FormatDocumentOnSave IntelliCode Extension 1.0 IntelliCode Visual Studio Extension Detailed Info Microsoft Azure Tools for Visual Studio 2.9 Support for Azure Cloud Services projects Microsoft Continuous Delivery Tools for Visual Studio 0.4 Simplifying the configuration of Azure DevOps pipelines from within the Visual Studio IDE. Microsoft JVM Debugger 1.0 Provides support for connecting the Visual Studio debugger to JDWP compatible Java Virtual Machines Microsoft Library Manager 2.1.113+g422d40002e.RR Install client-side libraries easily to any web project Microsoft MI-Based Debugger 1.0 Provides support for connecting Visual Studio to MI compatible debuggers Microsoft Visual Studio Tools for Containers 1.2 Develop, run, validate your ASP.NET Core applications in the target environment. F5 your application directly into a container with debugging, or CTRL + F5 to edit & refresh your app without having to rebuild the container. Mono Debugging for Visual Studio 16.10.15 (552afdf) Support for debugging Mono processes with Visual Studio. NuGet Package Manager 5.11.0 NuGet Package Manager in Visual Studio. For more information about NuGet, visit https://docs.nuget.org/ ProjectServicesPackage Extension 1.0 ProjectServicesPackage Visual Studio Extension Detailed Info Razor (ASP.NET Core) 16.1.0.2122504+13c05c96ea6bdbe550bd88b0bf6cdddf8cde1725 Provides languages services for ASP.NET Core Razor. SQL Server Data Tools 16.0.62111.25150 Microsoft SQL Server Data Tools SQLite & SQL Server Compact Toolbox 4.8 SQLite & SQL Server Compact Toolbox adds scripting, import, export, rename, query execution and much more to SQL Server Compact & SQLite Data Connections. TypeScript Tools 16.0.30526.2002 TypeScript Tools for Microsoft Visual Studio Visual Basic Tools 3.11.0-4.21602.3+fc14a1355c0461af5110b74b26f6478f22d26565 Visual Basic components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used. Visual F# Tools 16.11.0-beta.21514.6+b6c2c4f53ea3a08fa603ea93d6d2f808a62a21d1 Microsoft Visual F# Tools Visual Studio Code Debug Adapter Host Package 1.0 Interop layer for hosting Visual Studio Code debug adapters in Visual Studio Visual Studio Container Tools Extensions 1.0 View, manage, and diagnose containers within Visual Studio. Visual Studio Tools for Containers 1.0 Visual Studio Tools for Containers Visual Studio Tools for Unity 4.11.4.0 Visual Studio Tools for Unity VisualStudio.DeviceLog 1.0 Information about my package VisualStudio.Foo 1.0 Information about my package VisualStudio.Mac 1.0 Mac Extension for Visual Studio Xamarin 16.11.000.197 (d16-11@6934992) Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android. Xamarin Designer 16.11.0.47 (remotes/origin/d16-11@e0d612363) Visual Studio extension to enable Xamarin Designer tools in Visual Studio. Xamarin Templates 16.10.5 (355b57a) Templates for building iOS, Android, and Windows apps with Xamarin and Xamarin.Forms. Xamarin.Android SDK 12.0.0.3 (d16-11/f0e3c2d) Xamarin.Android Reference Assemblies and MSBuild support. Mono: c633fe9 Java.Interop: xamarin/java.interop/d16-11@476bb5b ProGuard: Guardsquare/proguard/v7.0.1@912d149 SQLite: xamarin/sqlite/3.35.4@85460d3 Xamarin.Android Tools: xamarin/xamarin-android-tools/d16-11@87af37b Xamarin.iOS and Xamarin.Mac SDK 15.2.0.17 (738fde344) Xamarin.iOS and Xamarin.Mac Reference Assemblies and MSBuild support. ```

Build Logs

Screenshots

For example: Tap the green "def" span on the first line. The TapGestureRecognizer for the blue "bcd" span at the end of the line gets triggered, even though I didn't tap on it. Then immediately afterwards the "def" TapGestureRecognizer is triggered as well.

image

Kas-code commented 2 years ago

https://github.com/xamarin/Xamarin.Forms/issues/10520 seems to be a related issue

SarthakGz commented 2 years ago

Also happening to me on android only.If span is having multiline line then tap-gesture only working when tapped precisely on last line only. Let me know of any workaround for now if found ?

Kas-code commented 2 years ago

Yes, that would seem to be produced by this bug. Tap-gesture works properly on last line of the span, but tapping anywhere on the line where the span starts triggers the tap gesture for both the line breaking span and other spans as well, even when tapped to the left of the line breaking span. @SarthakGz Do you get multiple hits to the Tapped event coming from two spans at the same time? A partial fix I have for now is to implement a throttling algorithm that ignores the incorrect tap event when two are triggered at the same time. If this is your issue then I can share code which helps with that.

Kas-code commented 1 year ago

Until this issue is fixed, is there a way to stop a span from breaking onto multiple lines? If I can disable line wrapping on the span, that will be good enough for now.