KeyboardHelper

Static helper for controlling and monitoring the soft keyboard on mobile devices.

Namespace: GamaLearn.Helpers Assembly: GamaLearn.Maui.Core

Overview

KeyboardHelper provides platform-specific methods to show/hide the soft keyboard, get its height, and monitor keyboard visibility changes. Essential for creating responsive UIs that adapt to keyboard appearance, especially for forms and chat applications.

Installation

dotnet add package GamaLearn.Maui.Core

Methods

ShowKeyboard(View view)

Shows the soft keyboard for the specified view.

Parameters:

view - The view to show the keyboard for (typically an Entry or Editor)

Returns: bool - True if the keyboard was shown successfully

using GamaLearn.Helpers;

bool shown = KeyboardHelper.ShowKeyboard(myEntry);

HideKeyboard(View? view = null)

Hides the soft keyboard.

Parameters:

view - The view that currently has the keyboard (optional)

Returns: bool - True if the keyboard was hidden successfully

KeyboardHelper.HideKeyboard();

// Or specify the focused view
KeyboardHelper.HideKeyboard(myEntry);

GetKeyboardHeight()

Gets the current height of the soft keyboard.

Returns: double - Keyboard height in device-independent units, or 0 if not visible

double height = KeyboardHelper.GetKeyboardHeight();

IsKeyboardVisible()

Gets whether the soft keyboard is currently visible.

Returns: bool - True if keyboard is visible

if (KeyboardHelper.IsKeyboardVisible())
{
    // Keyboard is showing
}

Events

KeyboardShown

Raised when the keyboard is shown.

Event Args: KeyboardEventArgs

Height - The keyboard height in device-independent units

KeyboardHelper.KeyboardShown += (sender, e) =>
{
    Debug.WriteLine($"Keyboard shown with height: {e.Height}");
    AdjustLayoutForKeyboard(e.Height);
};

KeyboardHidden

Raised when the keyboard is hidden.

KeyboardHelper.KeyboardHidden += (sender, e) =>
{
    Debug.WriteLine("Keyboard hidden");
    RestoreLayout();
};

Platform-Specific Setup

Android

IMPORTANT: On Android, you must call StartMonitoring to enable keyboard height detection and events:

using GamaLearn.Helpers;
using Microsoft.Maui.Platform;

public class MainActivity : MauiAppCompatActivity
{
    protected override void OnCreate(Bundle? savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        // Start monitoring keyboard on Android
        var rootView = Window?.DecorView?.RootView;
        if (rootView is not null)
        {
            KeyboardHelper.StartMonitoring(rootView);
        }
    }

    protected override void OnDestroy()
    {
        KeyboardHelper.StopMonitoring();
        base.OnDestroy();
    }
}

iOS / MacCatalyst

Keyboard events are automatically monitored. No additional setup required.

Windows

Keyboard management on Windows uses focus management. The on-screen keyboard is controlled by the OS.

Usage Examples

Auto-Scroll Chat Input

public partial class ChatPage : ContentPage
{
    public ChatPage()
    {
        InitializeComponent();

        KeyboardHelper.KeyboardShown += OnKeyboardShown;
        KeyboardHelper.KeyboardHidden += OnKeyboardHidden;
    }

    private void OnKeyboardShown(object? sender, KeyboardEventArgs e)
    {
        // Scroll to bottom when keyboard appears
        var messagesList = this.FindByName<CollectionView>("MessagesList");
        messagesList.ScrollTo(messagesList.ItemsSource.Cast<object>().LastOrDefault());

        // Add padding to avoid keyboard overlap
        var inputLayout = this.FindByName<Grid>("InputLayout");
        inputLayout.TranslateTo(0, -e.Height, 250, Easing.CubicOut);
    }

    private void OnKeyboardHidden(object? sender, EventArgs e)
    {
        // Restore layout
        var inputLayout = this.FindByName<Grid>("InputLayout");
        inputLayout.TranslateTo(0, 0, 250, Easing.CubicOut);
    }

    protected override void OnDisappearing()
    {
        base.OnDisappearing();

        KeyboardHelper.KeyboardShown -= OnKeyboardShown;
        KeyboardHelper.KeyboardHidden -= OnKeyboardHidden;
    }
}

Dismiss on Tap Outside

public partial class FormPage : ContentPage
{
    public FormPage()
    {
        InitializeComponent();

        // Add tap gesture to background
        var tapGesture = new TapGestureRecognizer();
        tapGesture.Tapped += OnBackgroundTapped;

        var background = this.FindByName<Grid>("BackgroundGrid");
        background.GestureRecognizers.Add(tapGesture);
    }

    private void OnBackgroundTapped(object? sender, EventArgs e)
    {
        // Hide keyboard when tapping outside input fields
        KeyboardHelper.HideKeyboard();
    }
}

public partial class LoginPage : ContentPage
{
    public LoginPage()
    {
        InitializeComponent();
    }

    private void OnUsernameCompleted(object sender, EventArgs e)
    {
        // Move to password field
        PasswordEntry.Focus();
    }

    private void OnPasswordCompleted(object sender, EventArgs e)
    {
        // Hide keyboard and submit
        KeyboardHelper.HideKeyboard();
        LoginCommand.Execute(null);
    }

    private void OnCancelClicked(object sender, EventArgs e)
    {
        KeyboardHelper.HideKeyboard();
        Navigation.PopAsync();
    }
}

Adaptive Layout

public class AdaptiveFormViewModel : ObservableObject
{
    private double contentMargin;
    public double ContentMargin
    {
        get => contentMargin;
        set => SetProperty(ref contentMargin, value);
    }

    public AdaptiveFormViewModel()
    {
        KeyboardHelper.KeyboardShown += OnKeyboardShown;
        KeyboardHelper.KeyboardHidden += OnKeyboardHidden;
    }

    private void OnKeyboardShown(object? sender, KeyboardEventArgs e)
    {
        // Push content up to avoid keyboard
        ContentMargin = -e.Height / 2;
    }

    private void OnKeyboardHidden(object? sender, EventArgs e)
    {
        ContentMargin = 0;
    }
}

<ContentPage>
    <ScrollView Margin="0,{Binding ContentMargin},0,0">
        <VerticalStackLayout>
            <Entry Placeholder="Username" />
            <Entry Placeholder="Password" IsPassword="True" />
            <Button Text="Login" />
        </VerticalStackLayout>
    </ScrollView>
</ContentPage>

Search Bar Focus

public class SearchViewModel : ObservableObject
{
    [RelayCommand]
    private void OpenSearch()
    {
        // Show search bar and keyboard
        IsSearchVisible = true;

        // Wait for UI to render, then show keyboard
        MainThread.BeginInvokeOnMainThread(async () =>
        {
            await Task.Delay(100);
            var searchEntry = GetSearchEntry();
            if (searchEntry is not null)
            {
                KeyboardHelper.ShowKeyboard(searchEntry);
            }
        });
    }

    [RelayCommand]
    private void CloseSearch()
    {
        KeyboardHelper.HideKeyboard();
        IsSearchVisible = false;
    }
}

Comment Input

public partial class PostDetailPage : ContentPage
{
    public PostDetailPage()
    {
        InitializeComponent();
    }

    private void OnAddCommentClicked(object sender, EventArgs e)
    {
        // Show comment input and keyboard
        CommentInput.IsVisible = true;
        CommentInput.Focus();
        KeyboardHelper.ShowKeyboard(CommentInput);
    }

    private async void OnSubmitCommentClicked(object sender, EventArgs e)
    {
        // Submit comment
        await SubmitCommentAsync(CommentInput.Text);

        // Hide keyboard and input
        KeyboardHelper.HideKeyboard();
        CommentInput.Text = string.Empty;
        CommentInput.IsVisible = false;
    }
}

public class InputDialogPage : ContentPage
{
    private readonly TaskCompletionSource<string?> tcs = new();

    public Task<string?> GetInputAsync() => tcs.Task;

    public InputDialogPage(string title, string placeholder)
    {
        Title = title;

        var entry = new Entry { Placeholder = placeholder };
        var submitButton = new Button { Text = "Submit" };
        var cancelButton = new Button { Text = "Cancel" };

        submitButton.Clicked += (s, e) =>
        {
            KeyboardHelper.HideKeyboard();
            tcs.TrySetResult(entry.Text);
        };

        cancelButton.Clicked += (s, e) =>
        {
            KeyboardHelper.HideKeyboard();
            tcs.TrySetResult(null);
        };

        Content = new VerticalStackLayout
        {
            Padding = 20,
            Spacing = 10,
            Children = { entry, submitButton, cancelButton }
        };

        // Show keyboard when page appears
        Appearing += (s, e) =>
        {
            entry.Focus();
            KeyboardHelper.ShowKeyboard(entry);
        };
    }
}

// Usage:
var dialog = new InputDialogPage("Enter Name", "Your name");
await Navigation.PushModalAsync(dialog);
string? result = await dialog.GetInputAsync();
await Navigation.PopModalAsync();

Best Practices

1. Unsubscribe from Events

✅ Good:
protected override void OnAppearing()
{
    base.OnAppearing();
    KeyboardHelper.KeyboardShown += OnKeyboardShown;
}

protected override void OnDisappearing()
{
    base.OnDisappearing();
    KeyboardHelper.KeyboardShown -= OnKeyboardShown;
}

❌ Avoid:
// Subscribing without unsubscribing (memory leak)
KeyboardHelper.KeyboardShown += OnKeyboardShown;

2. Android Setup Required

✅ Good (Android):
// In MainActivity
protected override void OnCreate(Bundle? savedInstanceState)
{
    base.OnCreate(savedInstanceState);
    var rootView = Window?.DecorView?.RootView;
    if (rootView is not null)
    {
        KeyboardHelper.StartMonitoring(rootView);
    }
}

❌ Avoid:
// Not calling StartMonitoring on Android
// Keyboard events won't work!

3. Wait for View to Render

✅ Good:
protected override async void OnAppearing()
{
    base.OnAppearing();
    await Task.Delay(100); // Let UI render
    KeyboardHelper.ShowKeyboard(myEntry);
}

❌ Avoid:
public MyPage()
{
    InitializeComponent();
    KeyboardHelper.ShowKeyboard(myEntry); // Too early, view not ready
}

Platform Behavior

iOS / MacCatalyst

Automatic keyboard monitoring via NSNotification
Keyboard height includes safe area insets
Events fire on UIKeyboard.WillShow/WillHide

Android

Requires StartMonitoring(rootView) call in MainActivity
Uses WindowInsetsCompat to detect keyboard
Height excludes safe area insets

Windows

Focus management only
Keyboard height always returns 0
On-screen keyboard managed by Windows OS

Tizen

Placeholder implementation
Keyboard control not currently supported

Troubleshooting

Events Not Firing (Android)

Make sure you called StartMonitoring:

// In MainActivity.OnCreate
var rootView = Window?.DecorView?.RootView;
if (rootView is not null)
{
    KeyboardHelper.StartMonitoring(rootView);
}

ShowKeyboard Not Working

Ensure the view has focus and is rendered:

protected override async void OnAppearing()
{
    base.OnAppearing();
    myEntry.Focus();
    await Task.Delay(100);
    KeyboardHelper.ShowKeyboard(myEntry);
}

Height Always Zero

On iOS, keyboard height is only available after KeyboardShown event fires. On Windows, keyboard height is not available.

Table of Contents

KeyboardHelper

Overview

Installation

Methods

ShowKeyboard(View view)

HideKeyboard(View? view = null)

GetKeyboardHeight()

IsKeyboardVisible()

Events

KeyboardShown

KeyboardHidden

Platform-Specific Setup

Android

iOS / MacCatalyst

Windows

Usage Examples

Auto-Scroll Chat Input

Dismiss on Tap Outside

Form Navigation

Adaptive Layout

Search Bar Focus

Comment Input

Best Practices

1. Unsubscribe from Events

2. Android Setup Required

3. Wait for View to Render

Platform Behavior

iOS / MacCatalyst

Android

Windows

Tizen

Troubleshooting

Events Not Firing (Android)

ShowKeyboard Not Working

Height Always Zero

See Also

Table of Contents

KeyboardHelper

Overview

Installation

Methods

ShowKeyboard(View view)

HideKeyboard(View? view = null)

GetKeyboardHeight()

IsKeyboardVisible()

Events

KeyboardShown

KeyboardHidden

Platform-Specific Setup

Android

iOS / MacCatalyst

Windows

Usage Examples

Auto-Scroll Chat Input

Dismiss on Tap Outside

Form Navigation

Adaptive Layout

Search Bar Focus

Comment Input

Modal Input Dialog

Best Practices

1. Unsubscribe from Events

2. Android Setup Required

3. Wait for View to Render

Platform Behavior

iOS / MacCatalyst

Android

Windows

Tizen

Troubleshooting

Events Not Firing (Android)

ShowKeyboard Not Working

Height Always Zero

See Also