import SwiftUI

// MARK: - View Extension for Placeholder
extension View {
    /// 为TextField和SecureField添加占位符功能
    /// - Parameters:
    ///   - shouldShow: 是否显示占位符
    ///   - alignment: 占位符对齐方式
    ///   - placeholder: 占位符视图构建器
    /// - Returns: 带有占位符的视图
    func placeholder<Content: View>(
        when shouldShow: Bool,
        alignment: Alignment = .leading,
        @ViewBuilder placeholder: () -> Content) -> some View {
        
        ZStack(alignment: alignment) {
            placeholder().opacity(shouldShow ? 1 : 0)
            self
        }
    }
}