ITextWatcher to entry handler .net maui android

Question

ITextWatcher to entry handler .net maui android

Anonymous

I am working on porting Xamarin forms renderers to .net maui handlers using below link. my project is multi project.

https://github.com/jsuarezruiz/mvpsummit2022-dotnet-maui.

when trying to implement ITextWatcher to custom entry in android getting error.

attaching the screenshot for the same.

Screenshot 2023-05-02 at 10.57.30 PM

Anyone can help on this

Rob Caplan - MSFT 6,032 Reputation points Microsoft Employee Moderator

2023-05-02T18:15:23.2+00:00

For help or questions on https://github.com/jsuarezruiz/mvpsummit2022-dotnet-maui. please post in that repo.

If you need help with adding an ITextWatcher to your own code please post what you are doing and the specific errors you are getting.

Please don't post screenshots of text such as code and error messages. They are inaccessible and difficult to work with.
Rob Caplan - MSFT 6,032 Reputation points Microsoft Employee Moderator

2023-05-02T18:16:40.1833333+00:00

Post duplicated at https://stackoverflow.com/questions/76157487/itextwatcher-to-entry-handler-net-maui
Anonymous

2023-05-03T10:35:34.42+00:00
Rob Caplan Thanks for the reply. I have changed the renderer code to handler using this link

MVP Summit 2022 - .NET MAUI samples link.

https://github.com/jsuarezruiz/mvpsummit2022-dotnet-maui

I have followed the steps mentioned in the above link.

when adding ITextWatcher to entry handler class getting error. asking to implement interface members which are not required. ex : IJavaObject.Handle, IJavaPeerable.Disposed . I need below methods only.

ITextWatcher.AfterTextChanged ITextWatcher.BeforeTextChanged ITextWatcher.OnTextChanged
Rob Caplan - MSFT 6,032 Reputation points Microsoft Employee Moderator

2023-05-03T23:53:47.68+00:00

Please edit the you are using to implement ITextWatcher and the errors into your question. Images of text--specifically including code and error messages--are inaccessible and difficult to read and to work with.

when adding ITextWatcher to entry handler class getting error. asking to implement interface members which are not required. ex : IJavaObject.Handle, IJavaPeerable.Disposed

A class which implements an interface must provide implementations of all methods of the interface. They are all required. Depending on the specific methods and needs, you may be able to stub them out.

Anonymous

Rob Caplan

I am changing in the renderer code to maui handlers code in multi project (Forms, iOS, Android) using the below link. https://github.com/dotnet/maui/wiki/Porting-Custom-Renderers-to-Handlers I am using class CustomKeyboardEditText to Create Native Control and calling SetNativeControl method in my renderer code like below

Copy
protected override EditText CreateNativeControl()
        {
            return new CustomKeyboardEditText(Context, Element);
        }


My Question is : What should i pass in place of Element in my handler code? How to add ITextWatcher in my handler code? my renderer implementation :

Copy
namespace LibraryTestAppMaui.Android
{
    public class FlatEntryRenderer : Xamarin.Forms.Platform.Android.AppCompat.ViewRenderer<FlatEntry, EditText>, ITextWatcher
    {
        bool disableTextUpdates;

        public FlatEntryRenderer(Context context) : base(context)
        {
        }
        protected override void OnElementChanged(ElementChangedEventArgs<FlatEntry> e)
        {
            base.OnElementChanged(e);

            if (e.OldElement == null)
            {
                var ctrl = CreateNativeControl();
                SetNativeControl(ctrl);
                Control.AddTextChangedListener(this);
                SetHintText();
                SetTextColor();
            }
        }
        void ITextWatcher.AfterTextChanged(IEditable s)
        { }
        void ITextWatcher.BeforeTextChanged(ICharSequence s, int start, int count, int after)
        { }
        void ITextWatcher.OnTextChanged(ICharSequence s, int start, int before, int count)
        {
            ((IElementController)Element).SetValueFromRenderer(Entry.TextProperty, s.ToString());
        }
        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            base.OnElementPropertyChanged(sender, e);
            if(e.PropertyName == Entry.PlaceholderProperty.PropertyName)
            {
                SetHintText();
            }
            else if(e.PropertyName == Entry.TextColorProperty.PropertyName)
            {
                SetTextColor();
            }
        }
        void SetHintText()
        {
            Control.Hint = Element.Placeholder;
        }
        void SetTextColor()
        {
            if(Element.TextColor == Xamarin.Forms.Color.Default)
            {
                Control.SetTextColor(Control.TextColors);
            }
            else
            {
                Control.SetTextColor(Element.TextColor.ToAndroid());
            }
        }
        protected override EditText CreateNativeControl()
        {
            return new CustomKeyboardEditText(Context, Element);
        }

        class CustomKeyboardEditText : EditText
        {
            readonly Entry entry;

            public CustomKeyboardEditText(Context context, Entry entry) : base(context)
            {
                this.entry = entry;
            }

            protected override void OnFocusChanged(bool gainFocus, FocusSearchDirection direction, Android.Graphics.Rect previouslyFocusedRect)
            {
                base.OnFocusChanged(gainFocus, direction, previouslyFocusedRect);
                if (entry is FlatEntry { IsBehindWebView: true })
                    return;
                if (gainFocus)
                {
                    CustomKeyboard.Instance.Show(entry);
                    if (entry.SelectionLength == 0 && Text?.Length > 0)
                    {
                        entry.SelectionLength = Text.Length;    // Move the cursor to the end of the input.
                    }
                }
                else
                {
                    CustomKeyboard.Instance.Hide();
                    entry.SelectionLength = 0;
                }
            }
        }
    }
}


**Below is my code changes to handler :**

namespace LibraryTestAppMaui.Android
{
    public class FlatEntryRenderer : ViewHandler<IFlatEntry, EditText>
    {
        public static IPropertyMapper<IFlatEntry, FlatEntryRenderer> PropertyMapper = new PropertyMapper<IFlatEntry, FlatEntryRenderer>(ViewHandler.ViewMapper)
        {
            [nameof(IFlatEntry.TextColor)] = MapTextColor,
            [nameof(IFlatEntry.PlaceHolder)] = MapPlaceHolder,
        };

        private static void MapPlaceHolder(FlatEntryRenderer handler, IFlatEntry entry)
        {
            handler.PlatformView?.SetHint(entry.PlaceHolder);
        }

        public static CommandMapper<IFlatEntry, FlatEntryRenderer> CommandMapper = new(ViewCommandMapper)
        {
            
        };

        public FlatEntryRenderer() : base(PropertyMapper, CommandMapper)
        {
        }

        protected override EditText CreatePlatformView()
        {
            return new CustomKeyboardEditText(Context, Element);
        }

        protected override void ConnectHandler(EditText nativeView)
        {
            //_watcher.Handler = this;
            //nativeView.AddTextChangedListener(_watcher);

            base.ConnectHandler(nativeView);
        }

        protected override void DisconnectHandler(EditText nativeView)
        {
            //nativeView.RemoveTextChangedListener(_watcher);
            //_watcher.Handler = null;

            base.DisconnectHandler(nativeView);
        }
        public static void MapTextColor(FlatEntryRenderer handler, IFlatEntry entry)
        {
            handler.PlatformView?.SetTextColor(entry.TextColor.ToAndroid());
        }

        class CustomKeyboardEditText : EditText
        {
            readonly Entry entry;

            public CustomKeyboardEditText(Context context, Entry entry) : base(context)
            {
                this.entry = entry;
            }

            protected override void OnFocusChanged(bool gainFocus, FocusSearchDirection direction, Android.Graphics.Rect previouslyFocusedRect)
            {
                base.OnFocusChanged(gainFocus, direction, previouslyFocusedRect);

                if (entry is IFlatEntry { IsBehindWebView: true })
                    return;

                if (gainFocus)
                {
                    
                    CustomKeyboard.Instance.Show(entry);
                    if (entry.SelectionLength == 0 && Text?.Length > 0)
                    {
                        entry.SelectionLength = Text.Length;    // Move the cursor to the end of the input.
                    }
                }
                else
                {
                    
                    CustomKeyboard.Instance.Hide();
                    entry.SelectionLength = 0;
                }
            }
        }

    }
}

I have created IFlatEntry and FlatEntry as mentioned in this link.
https://github.com/dotnet/maui/wiki/Porting-Custom-Renderers-to-Handlers

Copy
namespace LibraryTestAppMaui.Controls
{
    public interface IFlatEntry : IView
    {
        public Color TextColor { get; }
        public string PlaceHolder { get; }

        void Completed();


    }
}


namespace LibraryTestAppMaui.Controls
{
    public class FlatEntry : View, IFlatEntry
    {
        public Color TextColor { get; set; }
        public string PlaceHolder { get; set; }
        public void Completed()
        {
            
        }
    }
}

getting below errors when trying to add ITextWatcher to FlatEntryRenderer

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'ITextWatcher.AfterTextChanged(IEditable?)' (CS0535) (LibraryTestAppMaui.Android)

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'ITextWatcher.BeforeTextChanged(ICharSequence?, int, int, int)' (CS0535) (LibraryTestAppMaui.Android)

Error CS0535: 'FlatEntryRenderer' does not implement interface member 'ITextWatcher.OnTextChanged(ICharSequence?, int, int, int)' (CS0535) (LibraryTestAppMaui.Android)

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaObject.Handle' (CS0535) (LibraryTestAppMaui.Android)

Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.SetJniIdentityHashCode(int)' (CS0535) (LibraryTestAppMaui.Android)

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.SetPeerReference(JniObjectReference)' (CS0535) (LibraryTestAppMaui.Android)

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.SetJniManagedPeerState(JniManagedPeerStates)' (CS0535) (LibraryTestAppMaui.Android)

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.UnregisterFromRuntime()' (CS0535) (LibraryTestAppMaui.Android)

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.DisposeUnlessReferenced()' (CS0535) (LibraryTestAppMaui.Android)

Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.Disposed()' (CS0535) (LibraryTestAppMaui.Android)

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.Finalized()' (CS0535) (LibraryTestAppMaui.Android)

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.JniIdentityHashCode' (CS0535) (LibraryTestAppMaui.Android)

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.PeerReference' (CS0535) (LibraryTestAppMaui.Android)

Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.JniPeerMembers' (CS0535) (LibraryTestAppMaui.Android)

 Error CS0535: 'FlatEntryRenderer' does not implement interface member 'IJavaPeerable.JniManagedPeerState' (CS0535) (LibraryTestAppMaui.Android)

1 answer

Your answer

Rob Caplan - MSFT 6,032 Reputation points Microsoft Employee Moderator

2023-05-02T18:15:23.2+00:00

For help or questions on https://github.com/jsuarezruiz/mvpsummit2022-dotnet-maui. please post in that repo.

If you need help with adding an ITextWatcher to your own code please post what you are doing and the specific errors you are getting.

Please don't post screenshots of text such as code and error messages. They are inaccessible and difficult to work with.
Rob Caplan - MSFT 6,032 Reputation points Microsoft Employee Moderator

2023-05-02T18:16:40.1833333+00:00

Post duplicated at https://stackoverflow.com/questions/76157487/itextwatcher-to-entry-handler-net-maui
Anonymous

2023-05-03T10:35:34.42+00:00

Rob Caplan Thanks for the reply. I have changed the renderer code to handler using this link

MVP Summit 2022 - .NET MAUI samples link.

https://github.com/jsuarezruiz/mvpsummit2022-dotnet-maui

I have followed the steps mentioned in the above link.

when adding ITextWatcher to entry handler class getting error. asking to implement interface members which are not required. ex : IJavaObject.Handle, IJavaPeerable.Disposed . I need below methods only.

ITextWatcher.AfterTextChanged ITextWatcher.BeforeTextChanged ITextWatcher.OnTextChanged
Rob Caplan - MSFT 6,032 Reputation points Microsoft Employee Moderator

2023-05-03T23:53:47.68+00:00

Please edit the you are using to implement ITextWatcher and the errors into your question. Images of text--specifically including code and error messages--are inaccessible and difficult to read and to work with.

when adding ITextWatcher to entry handler class getting error. asking to implement interface members which are not required. ex : IJavaObject.Handle, IJavaPeerable.Disposed

A class which implements an interface must provide implementations of all methods of the interface. They are all required. Depending on the specific methods and needs, you may be able to stub them out.

Answer 1

Hello,

For how to migrate Renderer to Handler, MAUI has officially provided detailed documentation.

Please refer to Migrate a Xamarin.Forms custom renderer to a .NET MAUI handler for more detailed information.

Best Regards,

Alec Liu.

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ITextWatcher to entry handler .net maui android

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