이제 좀 더 고급 기능들을 알아볼게요! 😎 이런 기능들을 마스터하면 진짜 프로 개발자가 될 수 있어요!

8.1 커스텀 컨트롤 만들기

자주 사용하는 UI 패턴은 커스텀 컨트롤로 만들면 재사용성이 높아져요. 예를 들어, 로딩 인디케이터가 있는 버튼을 만들어볼게요:

public class LoadingButton : ContentView
{
    private readonly Button _button;
    private readonly ActivityIndicator _activityIndicator;
    
    public static readonly BindableProperty TextProperty = 
        BindableProperty.Create(nameof(Text), typeof(string), typeof(LoadingButton), default(string), propertyChanged: OnTextChanged);
    
    public static readonly BindableProperty IsLoadingProperty = 
        BindableProperty.Create(nameof(IsLoading), typeof(bool), typeof(LoadingButton), default(bool), propertyChanged: OnIsLoadingChanged);
    
    public static readonly BindableProperty CommandProperty = 
        BindableProperty.Create(nameof(Command), typeof(ICommand), typeof(LoadingButton), null);
    
    public string Text
    {
        get => (string)GetValue(TextProperty);
        set => SetValue(TextProperty, value);
    }
    
    public bool IsLoading
    {
        get => (bool)GetValue(IsLoadingProperty);
        set => SetValue(IsLoadingProperty, value);
    }
    
    public ICommand Command
    {
        get => (ICommand)GetValue(CommandProperty);
        set => SetValue(CommandProperty, value);
    }
    
    public LoadingButton()
    {
        _button = new Button();
        _activityIndicator = new ActivityIndicator { IsVisible = false, Color = Color.White };
        
        var grid = new Grid();
        grid.Children.Add(_button);
        grid.Children.Add(_activityIndicator);
        
        Content = grid;
        
        _button.Clicked += OnButtonClicked;
    }
    
    private void OnButtonClicked(object sender, EventArgs e)
    {
        Command?.Execute(null);
    }
    
    private static void OnTextChanged(BindableObject bindable, object oldValue, object newValue)
    {
        var control = (LoadingButton)bindable;
        control._button.Text = (string)newValue;
    }
    
    private static void OnIsLoadingChanged(BindableObject bindable, object oldValue, object newValue)
    {
        var control = (LoadingButton)bindable;
        bool isLoading = (bool)newValue;
        
        control._activityIndicator.IsVisible = isLoading;
        control._activityIndicator.IsRunning = isLoading;
        control._button.IsEnabled = !isLoading;
    }
}

이제 XAML에서 이렇게 사용할 수 있어요:

<local:LoadingButton Text="로그인" 
                     IsLoading="{Binding IsLoading}" 
                     Command="{Binding LoginCommand}" />

커스텀 컨트롤을 만들면 코드 재사용성이 높아지고, UI 일관성도 유지할 수 있어요. 진짜 유용함! 👍